- How long does it take for the compost to ripen?
- 1. You don’t cover up food scraps.
- 2. There’s not enough diversity.
- 3. You chop everything into tiny pieces.
- 4. You don’t keep enough leaves on hand.
- 5. You add too much grass.
- 6. You pile too much compost on your garden.
- Turning Your Compost Heap – How To Aerate A Compost Pile
- Why Turning Compost Helps
- How to Aerate Compost
- How Often to Turn Compost
- Turning the Pile
- Adding New Material
- Curing the Pile
- Related Questions
- How Often to Turn a Compost Tumbler
- Why You Need to Turn Your Compost Tumbler
- How Often Should You Turn Your Heap?
- Location & Appearance
- Adding Materials
- Why should I compost?
- How can I set up a composting bin or pile?
- What can I compost?
- Is there anything I can’t compost?
- How long does composting take?
- How can I use my compost?
- Can I compost inside my home?
- Everything You Need to Start Composting
- Pros & Cons of Open Air Composting
- How Composting Works
- What is a compost heap?
- Composting Grass Clippings
- From the Kitchen
- Materials to Avoid
- A Word About Activators
- Speeding Up the Compost Process
- When is Compost Finished?
- The Importance of Mature Compost
- Hot Piles
- Cool Piles
- The composting process
- The organisms that help
- What does and doesn’t go in?
- What else can be composted?
- Composting at home
How long does it take for the compost to ripen?
The short answer: your compost will be finished in six months to a year.
It will finish faster if you turn it, slower if you don’t.
(A picky correction to your question: compost will turn into humus, not actually soil.)
Rumor is that compost can be finished in as little as a few weeks, under ideal conditions. (I’ve never seen it.)
Folks who do vermicomposting (i.e. with worms) claim that 1 pound of worms will devour half their body weight per day, leaving just castings (worm poo). Worms can help the composting process, but keep in mind that if you heat up your pile by turning it you will either kill the worms or they will leave because they’re uncomfortable.
Yes, the process can stop. Especially if it gets cold — but it will restart once it warms up. It will also stop (really, it will probably just slow down a lot) if the bacteria inside the pile use up all of the oxygen. This is why turning the pile reactivates the process, because it introduces air.
I like the idea of “milestones” — this is a good question:
- Temperature: Is it hot? I have a thermometer with an 18″ probe that I can stick into my pile. If it is warmer than ambient temperature, then the bacteria are working inside the pile. (In summer when it’s 80°F outside, I’m happy if my pile is 100-120°F; in winter when it’s 30°F, I’m happy if the pile is 40°F.)
- This is also a cue to know when to turn the pile. Once the temperature starts dropping, it’s time to turn it.
- If you turn the pile and it doesn’t heat up any more, then you know it’s close to being finished.
- Smell: As you mention, you want a nice earthy smell. If it smells sour or rotten you’ve probably got too much water and not enough air. If it smells of ammonia, you’ve got too much nitrogen (“greens”) and not enough carbon (“browns”).
- Moisture: The pile should be about as damp as a wrung-out sponge. Any less water and the microbes can’t thrive. Any more water and they will suffocate because air can’t move as well.
- Texture: Perfectly finished compost has a fine texture with no large chunks — certainly nothing recognizable from the initial feedstock. (In my experience this never happens either — there’s always something left over from what you started with. If you want “perfect” compost, e.g. for starting seeds, it’s easy enough to sift the compost so you take the fine stuff and leave behind the chunks to compost further in your next batch.)
A couple of things to keep in mind:
- If you’re constantly adding new material to the composter, you’ll never get a complete batch of finished compost. There will always be something fresh in there. That’s why you see a lot of recommendations for “three bin” systems: add fresh material to one bin, the second bin is in the process of finishing, and the third bin is finished and is where you take compost from when you need it.
- You said kitchen scraps “and stuff”. Not sure what the “stuff” is, and you must have a good balance if it doesn’t stink, but make sure you’re adding enough “browns” — carbon-heavy materials like autumn leaves, shredded cardboard or black and white newspaper, straw, etc.
Truly messing up your compost is hard to do. Throw organic matter in a pile outdoors and it will break down eventually, even if you never look at it again. “There’s no right way to compost,” says Rick Carr, compost expert at the Rodale Institute’s organic farm. “I’ll never tell someone they’re composting wrong, or insist that a 75-year-old needs to go out and turn her compost pile twice a year with a pitchfork’
But if you want to save yourself some trouble with pests while making compost that’s richer in nutrients and easier to maintain, Carr is your go-to guy. Here’s what he says people commonly do that can cause composting problems, and how to fix it.
1. You don’t cover up food scraps.
There are three important reasons to cover up food scraps in your pile: 1) so it doesn’t get smelly, 2) so the raccoons and other critters don’t come knocking, and 3) to ensure you maintain a good balance of green and brown material.
Carr uses a lasagna-style method in his own compost pile: He starts with a layer of dried leaves on the bottom and creates a nest in the middle for his food waste. Then he covers the food waste with another thick layer of brown material, making sure none of the food waste is peeking through. He likes to keep his kitchen scraps in a five-gallon bucket with a tight lid until he has enough for a complete lasagna layer.
2. There’s not enough diversity.
“If you put a lot of the same thing in your compost, it will be uniform in nutrients and microbes,” Carr explains. So even though you’ll eventually end up with beautiful black soil if you only ever add lettuce stems, potato peels, and yard waste to your pile, it won’t have the diversity of nutrients and good bacteria that really makes compost valuable in the garden. Carr says you can compost just about any scraps that come out of your kitchen, which has the double benefit of diverting food waste from landfills and giving you a superior final product all at once. “The only things that should never go in your compost pile are glass, metal, styrofoam, and plastic,” he says.
Carr also adds that you absolutely can compost meat scraps (he does), though doing so is somewhat controversial. The reason people often warn against composting meat is that it can attract vermin and may not decompose quickly and safely in a backyard pile that isn’t hot enough to kill off pathogens. On the flip side, fish and meat are rich in nutrients that make great fertilizer. Beginners should stick with plant waste until they feel they’ve mastered the composting process.
3. You chop everything into tiny pieces.
Diversity matters when it comes to size, too. Some people think that the more you chop up your food and yard waste, the better results you’ll have with your compost. While it’s true that cutting things up can accelerate decomposition, too much chopping can lead to a soupy, soggy pile. That’s because if you cut everything into tiny pieces, your pile will lack pore spaces for air, and air is crucial to the decomposition process.
Carr uses the example of an apple: Cutting it into quarters would be beneficial, but putting it in a blender would hurt your compost as well as waste of energy. On a bigger scale, there’s really no reason to mulch your leaves.
4. You don’t keep enough leaves on hand.
After you rake your leaves this fall, don’t toss them in the incinerator or bag them for the trash collector. Since you need lots of brown leaves for layering in your compost pile throughout the year, Carr advises saving them up if you have the space. He packs his in several large metal trash cans, or you could also put them in a few trash bags inside your shed. This way you’ll always have enough brown waste to cover up your food scraps during summer months. If you run out of leaves, Carr says you can purchase a bale of straw instead.
5. You add too much grass.
Composting may seem like the organic solution to unwanted grass clippings, but Carr says they’re actually not that beneficial to your pile. “Clumps of grass form mats that block the airflow in your pile, which can make it dense and soggy,” he explains.
Grass is also high in nitrogen, which can throw off the balance of your pile and make things stinky. If you really want to put grass in your pile, mix it with dry leaves as you’re adding it. But really, you’re much better off just leaving clippings where they fall so they can help fertilize your lawn.
6. You pile too much compost on your garden.
When it comes to actually using your finished compost, there can be a tendency to go overboard. For starting seeds, you should never use 100% compost because it holds too much water and has a high mineral salt content, which prevents seeds from germinating. Carr says you can amend your potting mix with 25 to 50% compost, but no more. As for your raised beds, he recommends mixing up to two inches of compost into your soil yearly. If the soil is well established, you may only need one inch of compost.
Turning Your Compost Heap – How To Aerate A Compost Pile
Compost in the garden is often called black gold, and for good reason. Compost adds an amazing amount of nutrients and helpful microbes to our soil, so it makes sense that you would want to make as much compost as you can in the shortest amount of time. Turning your compost heap can help with this.
Why Turning Compost Helps
At a basic level, the benefits in turning your compost come down to aeration. Decomposition happens because of microbes and these microbes need to be able to breathe (in a microbial sense) in order to live and function. If there is no oxygen, these microbes die off and decomposition slows down .
Many things can create an anaerobic (no oxygen) environment in a compost pile. All of these problems can be reduced or eliminated by turning your compost. These can include:
- Compaction – This is the most obvious way that turning can aerate a compost pile. When the particles in your compost get too close to each other, there is no room for air. Turning compost will fluff your compost heap and create pockets where oxygen can get inside the pile and supply the microbes.
- Too much moisture – In a compost pile that is too wet, the pockets in between the particles will be filled with water rather than air. Turning helps to drain away the water and reopen the pockets to air instead.
- Over consumption by microbes – When microbes in your compost pile are happy, they will do their job well — sometimes too well. The microbe near the center of the pile may use up the nutrients and oxygen they need to survive and then they will die off. When you turn the compost, you mix the pile up. Healthy microbes and undepleted material will be mixed back into the center of the pile, which will keep the process going.
- Overheating in the compost pile – This is closely related to over consumption as when microbes do their jobs well, they also produce heat. Unfortunately, this same heat can kill off the microbes if the temperatures get too high. Mixing the compost up will redistribute the hot compost in the center into the cooler outer compost, which will help keep the overall temperature of the compost pile in the ideal range for decomposition.
How to Aerate Compost
For the home gardener, the ways to turn the compost pile is typically limited to either a composting tumbler or manual turning with a pitchfork or shovel. Either of these methods will work well.
A compost tumbler is typically bought as a complete unit and only needs the owner to turn the barrel regularly. There are also DIY directions available on the Internet for building your own compost tumbler.
For gardeners who prefer an open compost pile, a single compost bin can be turned by simply inserting your shovel or fork into the pile and literally turning it over, much like you would toss a salad. Some gardeners with enough space opt for a double or triple compost bin, which allows them to turn the compost by moving it from one bin to the next. These multi-bin composters are nice, as you can be sure that from top to bottom the pile has been thoroughly mixed.
How Often to Turn Compost
How often you should turn compost depends on a number of factors including size of the pile, green to brown ratio and amount of moisture in the pile. That being said, a good rule of thumb is to turn a compost tumbler every three to four days and the compost pile every three to seven days. As your compost matures, you can turn the tumbler or pile less frequently.
Some signs that you may need to turn the compost pile more frequently include slow decomposition, pest infestations and smelly compost. Be aware that if your compost pile starts to smell, turning the pile may make the smell worse, initially. You may want to keep wind direction in mind if this is the case.
Your compost pile is one of the greatest tools you have to make a great garden. It only makes sense that you would want to make the most of it. Turning your compost can make sure you get the most out of your compost pile as fast as possible.
for Mixing the Pile
Turning the Pile
Hot piles require aeration because the micro-organisms use up the oxygen in their close quarters fairly quickly. Cool piles also benefit from occasional turning, which will interrupt any anaerobic processes that may be getting under way in the oxygen-deprived depths of the pile. Any pile that has gone anaerobic or started producing ammonia should be turned immediately. You won’t have to guess whether one of these problems has occurred; the smells will tip you off.
While turning remains the time-honored method of aerating a compost pile, compost aerators reduce or even eliminate the need for that laborious undertaking. There’s more on these under Tools for Dealing with the Pile. Even a length of rebar can be pressed into service.
At Planet Natural we have everything you need for turning kitchen scraps — including meat, bones and dairy — into nutrient rich soil supplements without the usual mess and odors, including attractive pails for collecting your kitchen throwaways.
Turning refers, of course, to mixing a pile, usually with a pitchfork. Just how this is done, and how frequently, depends on your method. A wire bin can be lifted up and set to one side; the pile can then be forked back into it. In some multi-bin systems, when one bin is emptied, the contents of the next are forked into it. Some composters pull everything out of a bin, then toss it back in bit by bit, incorporating new material as they go.
Turning accomplishes two primary purposes: it aerates a pile and it moves material from the relatively cool, inactive periphery to the active center.
A compost aerator lifts material from the bottom of the pile up to the top. That material, of course, gets lots of oxygen, and the process opens up pathways for air and “fluffs” the whole pile to some degree. What it doesn’t do is move feedstock at the edge into the center.
Jim McNelly’s method, described in “Mixing it Up: Hot, Hot, Hot,” needs virtually no maintenance. This pile is built on a grate or openwork pile of sticks and stones and made of ingredients mixed before they’re put in the bin which have been inoculated with mature, active compost. It can be aerated simply with a piece of half-inch rebar. He recommends making holes three to six inches apart that reach all the way through the heap. Such a pile, he says, will stay hot for weeks without turning.
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When and How Often?
There’s no absolutely hard and fast rule for when to aerate, because it depends on how wet the pile was to begin with and how quickly it dries out, which depends at least in part on how humid it happens to be in your back yard not only usually, but this week. The rule of thumb for an active, hot pile is every three days until it stops heating up.
Some over-enthusiastic composters rush out after a day and turn the pile. This is a bit too much of a good thing. Turning too often (every day) disrupts the formation of the fungi and actinomycetes that do much of the composting work and may prevent the pile from heating up completely. For the fastest, most efficient decomposition, a pile should be left essentially alone to “cook” until it starts to cool. Then it should be aerated at once and left again. (“Essentially” means that it’s okay to add small batches of stuff to the center of the pile as described under adding new material, below.)
To get a reading of how the pile is doing, wait at least two days after assembling it, then pull away some of the surface material. Six inches down, the pile should be noticeably warm if not downright hot. Check the pile each day, covering the hole after each test. When the material is clearly cooling down, it’s time to turn it.
A compost thermometer thrust into the center of a pile makes it even easier to figure out what’s going on in there. It can also give startling evidence of how hot a hot pile gets. A good, hot pile will reach at least 130°F (54°C) and stay there for two to four days. When the temperature drops back down to about 100°, turn the pile — and watch the temperature soar.
Adding New Material
Most instructions for how to compost recommend batch systems in which you build a pile and then add no new material to it until it has finished heating up and cooling down. The implication is that only batch piles are hot piles because new material will cool the pile down and will be behind the stuff that’s already cooking.
A few experts, however, point out that once a pile is truly up and running, it can easily absorb new material without necessarily being slowed down. Kitchen garbage, especially, which tends to be soft and fairly high in nitrogen, can be dug into the center of a hot pile where it will disappear within days.
Such additions, if made deep enough in the pile, can reduce the need for turning. Turning, after all, is necessary primarily to aerate the pile and digging new material into it can accomplish this in part. Don’t expect additions to entirely replace turning. Only turning will re-aerate the entire pile, unless you have managed to find a way to continuously aerate it.
When the garden season is crankin’, you want to transform garden waste into premium organic matter — now. The CompostWizard Dueling Tumbler makes it happen. This small-batch workhorse keeps two separate bins going so the finished product is never more than a few days away.
Large quantities of new material can also be incorporated into a working pile when it is turned. The most thorough mixing will be accomplished on a tarp outside the bin, but interspersing thin layers of new and old material will also mix them sufficiently. Fork six inches or so of the old pile into its new bin, then add several inches of new material, and continue until the bin is full. If your active pile was good and hot, it should heat back up again within a day or two.
If you need compost in the shortest possible time, then use a pure batch system, adding nothing to the pile once it’s built. But if you want to compost the maximum amount of material with maximum efficiency, keep adding material to the center of the pile as it cooks and turn the whole heap whenever it starts to cool, incorporating new material as you do.
Curing the Pile
Even when the hot pile has stopped heating up, it still needs to cure for a couple of weeks before it is ready for use. Heat can become such a focus of quick composting that gardeners forget that several important degradation processes go on only at cooler temperatures.
As the heat-loving thermophilic bacteria die off, mesophilic bacteria that thrive at temperatures between 70 and 100°F (21-38°C) re-establish themselves and continue the composting process. Fungi and actinomycetes, which can be suppressed at high thermophilic temperatures, also flourish at this time. Both play important roles in breaking down tough lignin and cellulose, much of which can withstand even the high temperatures of hot composting.
Fungi and actinomycetes are not the only organisms that return to the pile as it cools. Most of the larger organisms — beetles and the precious garden worm — can’t withstand the temperatures in a hot pile, so they migrate elsewhere as the temperature rises. But as its heat moderates, they move back in. These migrations ensure that when the compost is spread, it will contain the full range of organisms that make compost so vital and so valuable. If compost is not left to cure, these macro-organisms do not have time to re-populate the pile.
What products to compost
You will be able to source all of the essential elements in order to build a great compost pile without having to look too far! As long as your carbon to nitrogen ratio is optimal (25-30:1) your compost pile will be breaking down properly. Here are some lists of acceptable additions:
Carbon Rich Material “Browns”
Cardboard (free of dyes)
Stems & twigs
Nitrogen Rich Material “Greens”
Kitchen food waste
Weeds (that have NOT gone to seed)
Things to Avoid
Diseased plant material
Manures from carnivorous animals
As for the rhododendron and holly leaves, you can definitely put them in your compost pile. However, it is a good idea to really chop or shred them up, as they take much longer to break down due to their fibrous and waxy make up. It really depends on how quickly you are trying to create usable compost. It might be a good idea to have a separate pile going that you incorporate those leaves into and another pile that you do not. That way you can have a pile you know will rapidly break down into garden goodness and have yet another ready to use later on. Good luck!
How Often to Turn a Compost Tumbler
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The biggest charm of a compost tumbler is its design that makes turning your heap easy. Lots of people tend to shy away from composting altogether after learning that they need to actually turn their heap to allow the ingredients and microbes in it to breathe.
Doing this would require manual labor, especially if your pile is large. Some folks also find it a bit gross, even though it’s not and would not even smell bad if you don’t include meats in it.
With a compost tumbler, you get to skip all the things some people find gross. Thanks to its design, this equipment won’t require you to use any other implements in turning your heap.
A hand crank or even just rolling the tumbler will already do the trick. This makes it a lot more convenient and attractive for lots of people.
The bigger question when it comes to turning a compost tumbler is how often you should be doing do it. While some people are sure that a perfectly constructed heap doesn’t require any turning at all, some beginners may find themselves confused with the opposing opinions.
To better understand what you should do with a compost tumbler, let’s get down to the most important points concerning this activity.
Why You Need to Turn Your Compost Tumbler
With some people saying that you don’t have to turn your pile, you might be wondering why others say that you should. There are three very good answers for this:
A compost tumbler is basically an enclosed container.
Compost tumblers, as the name suggests, are enclosed containers that tend to trap moisture and heat inside. While the heat is always good for your compost, excessive moisture is not. Turning your heap is said to help increase the heat inside the tumbler, so it’s said to be very helpful.
As for the moisture, turning alone might not get rid of the excess liquids in the heap. However, when you add browns to adjust the moisture levels, turning can help distribute the additional ingredients. This will then help absorb the extra moisture and help balance out the heap.
Turning keeps the heap well-aerated.
The most important reason for turning your compost heap is to aerate the microbes that are working hard to decompose your waste. By turning your heap, the microbes get exposed to air.
It also creates new passageways for air. As compost tumblers are raised from the ground, it doesn’t give access to earthworms that make air tunnels in a heap. Turning will compensate for this.
Oxygen helps sustain the microbes in your compost, so you should make sure that they get enough. Otherwise, they might just die and slow down the decomposition process altogether.
It solves various composting issues.
Turning your pile is also one of the best solutions for several problems that you might come across with during the composting process. It can help handle foul odors, keep pests away, and increase the temperature of your heap. All of these make it an essential part of composting.
How Often Should You Turn Your Heap?
Compost tumblers are designed to make turning your heap easier, so that’s definitely one of their charms. This makes turning a no-brainer. It’s the amount of turning that you should be quite particular about.
It’s no secret that composting can be a tricky activity as it can require you to be very specific about what you should and shouldn’t do. To make sure that you’ll get the best results, you might want to avoid the things you shouldn’t do so it won’t affect the speed of your composting process.
For this, lots of people worry about how often they should turn their heap now that it’s very easy to do.
Some people say that there’s no such thing as too much turning. With commercial equipment continuously turning compost, it shouldn’t be a problem if you do the same for your composter at home.
However, there are many accounts of compost clumping after being turned too often. This can affect the speed of maturity of your compost, so you might want to avoid it.
This is one of the many reasons why some folks say that turning your heap a few times a week will already suffice.
But then again, there are also those who recommend turning every day which can further add to a beginner’s confusion. Many compost tumbler manufacturers note that you need to turn the tumbler at least once daily, so there’s certainly lots of contrasting opinions about this activity.
So, what should you do? It might be best to turn by feel on many occasions. Consider the temperatures inside and outside your tumbler to decide how much turning you should do. If it’s cold outside and your compost isn’t heating up nicely, turn more often.
If you live somewhere warm and your compost has a nice balance of green and browns, you might need less turning. It’s also recommended to turn less as your compost matures.
There are so many factors that can affect the speed of your compost maturity, so it’s hard to pin down a hard and fast rule for turning. It will be best for you to learn how to experiment and assess your heap, so you can take the right adjustments to achieve the best results.
It might seem daunting at first, but with a better understanding of composting, you will surely get the hang of it in no time.
for Home & Garden
Composting, the practice of making organically rich soil amendments from yard, kitchen and other wastes, requires a number of conditions but is dependent on one thing: the microbes responsible for decomposition. These single-cell organisms, working through strength in numbers, turn your compostable materials into the rich humus that’s the foundation of all great growing soils. Supply these microscopic creatures with favorable materials and conditions and they’ll reward you and your gardens with healthy, productive plants.
We’ll talk about all the things that composting requires — oxygen, moisture, heat, the makeup and balance of compostable materials, not to mention practical requirements — locations, containers and the work involved (as little or as much as you like)– but first, some background on the microbes who facilitate the composting processes.
There are two general classes of composting microbes, the aerobes that work when oxygen (from air) is present, and the anaerobes, which work when it’s not. The kind of microbes you’ll be encouraging depends on the kind of composting you’ll do–ventilated, aerobic composting (the most common; piles, heaps and tumblers) or sealed-container anaerobic composting.
Here, shown as equations, are the basic components for both kinds of composting and what each type of microbial action yields (originally published by The Composting Council of Canada):
organic materials + water = carbon dioxide + methane + hydrogen sulfide + energy
organic materials + oxygen + water = carbon dioxide + water + energy
When we think composting, we’re almost always thinking of the heaps, bins, ventilated barrels, and other types of aerobic composting. The naturally occurring aerobic microorganisms that populate them require air and its oxygen to live. These microorganisms “eat” their way through the pile’s organic matter, the mix of yard, kitchen, and other green waste that makes up compost. As they consume this organic matter, they change it chemically, molecule by molecule. The digestion process, as the equation shows, give off energy (heat), water, and carbon-dioxide in the process.
Where do the aerobes come from? The classic Bible of composting, Let it Rot! points out that composting microorganisms are already everywhere in soil, so it’s not really necessary to add them to a pile.
Since its first edition in 1975, Let it Rot! has helped countless gardeners recycle household garbage, grass clippings and other waste materials into useful, soil-nourishing compost. It’s the classic guide to turning household waste into garden gold!
It’s true that most piles will take up aerobes from soil and surrounding environment and, provided the proper temperatures and moisture levels plus an occasional turning to replace consumed oxygen, and will eventually produce modest result. But inoculating a pile either with a compost activator available through organic gardening stores or finished compost already rich in micro-organisms from a neighbor or commercial source, can get it off to a quick and hot start. Sprinkling your chosen material between layers as they accumulate, a variation of the classic “lasagna-style” of composting (PDF), rather than pouring it on top of a finished pile ensures a better distribution of inoculants, and a correspondingly quick start to the composting process.
Any sealed composting system depends on anaerobic micro-organisms. If you fill a plastic bag with table scraps and yard waste and set it in the sun, it’s anaerobic micro-organisms that will break down that material. The result will be a soupy, foul-smelling mess higher in acids than solid compost, but perfectly useable as a soil amendment.
Anaerobes require organic material and water to do their work, giving off carbon dioxide, methane, hydrogen sulfide, and energy. Methane is of course a potent greenhouse gas, while hydrogen sulfide provides an equally potent smell of rotten eggs to an anaerobic pile. Large scale, municipal and commercial compost operations of the kind that process restaurant and other food waste have found ways to utilize the gases released by this kind of composting.
In a compost heap, however, large populations of anaerobic microorganisms, resulting from a lack of oxygen, usually spell trouble. The anaerobic process is slower than the aerobic, and can produce the kind of smelly pile that doesn’t foster good neighbor relations.
The Bokashi System is an anaerobic, self-contained method of composting table and other kitchen scraps that is odorless and can fit neatly under a kitchen sink or other indoor places. Aside from its Bokashi page, this site concentrates on aerobic composting.
The needs of your microbes — food, water, warmth, oxygen — are all key ingredients. The “food” means sources of carbon– brown materials including dead leaves, pine needles, and sawdust — and nitrogen sources–green waste including kitchen scraps, fresh cut grass, and additives such as blood or bone meal– in a ratio of 25 parts brown materials to 1 part green. See “What To Use” for a detailed discussion of what to feed your pile for best results.
The microbes that do the dirty work in the compost pile require water for survival, but it can be hard to judge how much water to add and when. Too much water can smother the pile, which means your organic waste won’t decompose and you’ll get a slimy and smelly pile that could well answer to the name “swamp thing.” Too little water and you’ll kill the bacteria and you won’t get your compost (see Managing Moisture in Compost).
One rule of thumb: the more green material (cut grass, weeds, leaves) you put in, the less water you’ll need to add. In fact, if you need to add dry ingredients such as straw or hay, soak the material first in water so it won’t dry out your compost pile. In general your compost should be moist, but not sopping wet.
If you are composting at home and you get a lot of rain, build a roof over the pile. This can be as simple as stringing a tarp. The reason you want to give your compost pile more shelter is because nutrients, or leachates, leak out when it rains. That’s not such a problem in a place where rainfall isn’t heavy, but if you get a lot of rain where you live, it can make a big difference. Too much water in the pile will slow down the process and can also make it slimy and icky. Best you add the moisture to your pile, rather than unpredictable Mother Nature.
For nearly forty years, the Original ComposTumbler has made it easy to turn the pile. Makes a complete batch, from start to finish, in just 14 days. Big enough for serious gardeners (holds 168 gallons, 22 cubic feet), easy enough for anyone!
Oxygen is also required by the aerobic microorganisms responsible for successful composting. Give your pile adequate ventilation and they will take care of the rest (see Aerobic Decomposition). You can make sure that the bacteria in your compost gets sufficient air by turning the pile often and well. Use a pitch fork, spade or compost aerator to mix your pile. If you’ve got a compost tumbler, you’ve got it easy. Just crank that lever. It’s also a good idea to turn the contents since it rearranges the decaying material. With a little care, you can move the less decomposed material on the edges to the middle of the pile to heat up. Don’t aerate your compost at all and it will break down slowly, possibly resulting in a slimy, dense, stinky pile.
The organisms responsible for composting can generate large amounts of heat, which raise the temperature of the pile or compost bin and, in turn, speeds up decomposition. A compost pile that is working well will produce temperatures of 140-160˚F. At these temperatures almost all weed seeds and plant diseases are killed. A “very hot” compost pile will generate temperatures of up to 170˚F for up to a week or more. Use a compost thermometer to measure the exact temperature at different locations inside the pile. A basic understanding of the temperature in a pile will help you know:
- When to turn it
- When to add more materials
- When to add water
- When it’s finished.
More information on microbes and composting is here, compliments of the University of Illinois Extension Service.
Location & Appearance
First you’ll want to select the most suitable location for composting. Your choice of where you make your compost should consider both function and aesthetics. Standard compost piles, contained in standing frames or not, are best tucked away by the garden, convenient for filling and using. Compost tumblers and other tidy, self-contained bins can be placed right by the back door convenient to kitchen scraps or near the plots where they’ll be emptied. Not even the crankiest neighbor who believes the myth of the smelly, pest attracting compost heap, considers them an eyesore. But, in consideration of appearances and good relations with your neighbors, not to mention your postal carrier, it’s probably not a good idea to place your compost bin, say, on the front lawn next to the mailbox. A behind-the-scenes location can go a long way to preserving good community relations. Some few towns and many homeowner associations have regulations and covenants. Know what might apply.
Manufactured in Sweden, the Green Johanna Composter works more quickly than standard units and can be used to break down all types of kitchen waste including cooked food, bones, fish and meat. This patented “closed” unit provides good ventilation and is easy to empty yet does not allow pests to access the contents.
Want to build your own compost bin? Here’s one simple solution: convert old shipping pallets (which you can usually pick up for free) into a compost “repository.” Use one for the bottom, placed with the slats running in the same direction as a garden fork will go when emptying it out. Pound in metal support poles and then add pallets by slipping them over the support poles to make your bin’s walls and you’re all set. The University of Missouri Extension offers several other examples for building a bin.
You can also skip the bin (a structure isn’t essential) and just have a compost pile or heap. In terms of appearances — and if your homeowners association is fussy — you may want to screen the pile from view by planting shrubs or a fence. You’ll also probably not want it by your picnic table or other areas outdoors where you entertain.
Choose a spot with good air circulation. Don’t place it next to your home or other wooden buildings as the decomposition process may cause damage. Partial shade is a good idea so the compost doesn’t get overheated. Also make sure the spot of land where you place your heap gets good drainage.
Close to the garden and to a water source are both good places for building a compost pile since it will be easier to move the materials to and from the garden and easier to water it. Another idea may be to place it near your kitchen to make it convenient to place table scraps on the pile or in the bin.
When adding organic waste to your compost, don’t squash the materials down to make more space. Squashing the contents will squeeze out the air that microbes in the compost pile need to turn your garbage into gold. (Instead you’ll be promoting the anaerobic microbes, which also do a good job converting carrot peels and other organic matter into compost but tend to be a lot smellier.)
Also be strategic about filling your bin. Include a mixture of brown fibrous ingredients and greens. A well-balanced “diet” will ensure that composting doesn’t take too long and that you don’t end up with a slimy, smelly heap. Also shred, dice or otherwise make scraps smaller, which will help the resident bacteria do a good job in converting the garbage into compost.
Finally, after you’ve added kitchen vegetable waste, throw some leaves or grass clippings on top of it. This will help keep things balanced, reduce smells and make your compost bin less attractive to critters who are trying to sniff out a free meal.
Note: As organic material in a compost pile heats up it breaks down and takes up less space. A compost pile can shrink up to 70% as it “cooks.”
Why should I compost?
It’s one of the most effective ways to minimize the amount of garbage your family sends to the landfill. Around 30% of what we throw away are food scraps and yard waste, says the EPA. Not only does this reduce methane gas, which is a major factor in global warming, but composting also controls trash can odor. And the biggest payoff? You’ll be left with a rich fertilizer you can use in your own garden or donate to your favorite cause.
How can I set up a composting bin or pile?
Choose an outdoor space for your compost — you need at least 3 square feet of space — and a bin. A closed bin is a good choice if you’re worried about the way your compost pile will look (or smell)! You can easily make a container, order one online (like FCMP Outdoor’s best-seller), or buy one at your local hardware or gardening store. Look for a bin that’s about 3 feet in diameter and not much taller than your waist. Use chicken wire or fencing to protect your bin from animals such as raccoons (or even the neighbor’s dog).
What can I compost?
You can add almost anything from your kitchen and garden — some surprising organic material includes egg shells, cut flowers, coffee grounds (and paper filters), old newspapers, tea and tea bags, hair (from pets and your own hair brush!), toothpicks, and even matches.
The trick is to aim for equal amounts of “green” waste and “brown” waste to keep your compost healthy. “Green” waste includes moist matter like fruits and vegetables and “brown” waste is dry matter can be items like wood shavings, dry leaves, or even old newspapers. Maintaining a balance is important is because “brown” materials are rich in carbon, feeding the organisms that break down the scraps and “green” materials supply nitrogen — key for building the cell structure of your new soil.
Your compost also needs oxygen and moisture. Without air, your pile will start to rot and smell. Moisture helps break everything down; sprinkle the compost with water every now and then, unless your scraps are wet enough on their own. With the right mixture, your compost should smell like nothing but earthy dirt.
Is there anything I can’t compost?
While they are compostable, dairy or animal products (even animal bones) will start to smell and attract pests, so toss those in your old-school garbage can. The same goes for fats, oils, and pet waste. Also, if you have a disease or insect ridden plant, don’t add it to the pile – it could contaminate your compost, making it unusable.
How long does composting take?
Over a few weeks, your food scraps will turn into soil. Turn your mixture over every week or two with a shovel or garden fork to mix it up. If you’re not seeing progress after a few weeks, add more “green” material and make sure you’re keeping the pile moist. If it’s smelly and wet, add more “brown” material and turn the compost more frequently. Also, break apart any big materials (like branches) to keep air flowing. Your compost is ready when it looks and smells like soil!
How can I use my compost?
Incorporate it into your garden beds or sprinkle it on top. Remember, compost is not a replacement for your soil, but rather acts as a natural fertilizer to nurture your soil and plants, so add it a couple of times a year for best results.
Can I compost inside my home?
Absolutely. Whether you’re in an apartment or a house without a backyard, you can set up a mini collection station right in your kitchen so you don’t have to trash food scraps. Experts from the Good Housekeeping Institute share their tips and tricks for making composting work no matter where you live:
1. Get a compost bin with a tight-fitting lid.
Whether you opt for a plastic bin or a stainless steel version, make sure it comes with a lid. Some plastic versions may absorb smells, explains Laurie Jennings, GH Institute director, which is why she uses an old stainless steel ice bucket with a matching lid on her countertop to collect compostable material.
2. Line your compost bin with biodegradable bags.
While it’s tempting to want to reuse plastic bags from the grocery store, these aren’t biodegradable and can defeat the purpose of your composting. Jennings swears by BioBag’s compostable bags (available in 3- and 13-gallon sizes) even after trying a number of more expensive brands.
3. Store full compost bags in your freezer.
You’ll want to replace the bag regularly so weeks-old scraps don’t start to stink up your space. Once your bin is at capacity, secure the bag, and place it in the freezer (yes, really!). This will make scraps easier to transport, eliminate any odor, halt active decomposition, and buy you some time before you’re able to get rid of them.
4. Find a local collection service or drop-off location.
If you don’t have a garden in which compost your scraps, see if your community offers collection services. Contact your local municipality or visit CompostNow’s site which lists participating services around the country — some even provide at-home starter kits and regular curbside pickup. The rules all depend on where you live. If you bring your own waste to a transfer station, check with them too: Many have designated compost areas.
If you live in an apartment or in a city without collection, you likely have to put in a little extra effort to donate your compost, but it’s worth it, explains Birnur Aral, Ph.D., director of the Health, Beauty & Environmental Sciences Lab, who is a home-composter in a community that doesn’t have a collection program.
“Every few weeks I bring my scraps to my daughter’s college where they have built a composting bin,” she says. “In the summer, I bring bags to my local farmer’s market and give them to a neighbor who sells produce and uses the compost at her farm upstate.” It’s a little way to give back.
Everything You Need to Start Composting
FCMP Outdoor IM4000 Tumbling Composter amazon.com $75.99 OXO Good Grips Easy Clean Compost Bin amazon.com $19.99 Epica Stainless Steel Compost Bin amazon.com $22.95 BioBag amazon.com $11.03
Pros & Cons of Open Air Composting
- Worms are naturally attracted to this method but will leave if conditions are not perfect.
- Temperature is paramount to success as is pH. If it doesn’t reach the required temperature it will not decompose or alternatively, may turn into a big slushy mess
- The nitrogen to carbon ratio is very important in this system
- It is preferable to have 2 to 3 bays in order to rotate the compost piles and allow time for the composting process to work. Use the oldest material first
- Three bays also helps speed up the composting
- An upturned bin must be filled from the top and emptied from the bottom
- You can only put worm friendly food in both these systems so as not to attract rats
- If you don’t have the right mix it can smell. Fine in the country but not suburbia
- It attracts annoying little vinegar flies often seen buzzing around the compost heap. Again fine in the country but something you or your neighbours may not like.
- Snakes and rats can nest and breed in the warm conditions
- Both these systems (Bay and Gedye) take a long time to decompose
- Turning to aerate is an essential part of this process
- Moving a Gedye can be hard work if they are too full.
- Turning the bays can be hard work.
- You may need to cover them when it rains so they don’t get too wet.
- You must spread the contents to see benefits in other parts of the garden
- Large amounts of green waste are required to obtain only a small amount of usable compost
- Ideal if you are a farmer and have lots of green waste to mulch with farm animal excrement
- Great if you have the time to monitor, turn etc
- Good for destroying seeds – but will only work if it reaches the required temperature
- Have been known to catch alight if they get too hot and dry – extreme conditions
- Can be left to sit for months at a time and eventually will turn to compost
- Some bins have aeration holes that attract flies
- Can smell if filled with the wrong materials and not turned
- Open air piles are great for the chooks to forage and catch food.
- Requires spreading around your garden
- Two to three piles are generally needed for this method to work effectively; therefore
- it takes up a lot of space in the garden
- is visible; &
- requires work
How Composting Works
Composting creates the ideal conditions for the natural decay or rotting processes that occur in nature. Composting requires the following:
- Organic waste – newspaper, leaves, grass, kitchen waste (fruits, vegetables), woody materials
- Soil – source of microorganisms
- Air – source of oxygen
The compost process
During composting, microorganisms from the soil eat the organic (carbon containing) waste and break it down into its simplest parts. This produces a fiber-rich, carbon-containing humus with inorganic nutrients like nitrogen, phosphorus and potassium. The microorganisms break the material down through aerobic respiration, and require oxygen that they get from the air you introduce when you turn the material in the compost bin. The microorganisms also require water to live and multiply. Through the respiration process, the microorganisms give off carbon dioxide and heat — temperatures within compost piles can rise as high as 100 to 150 degrees Fahrenheit (38 to 66 C). If the compost pile or bin is actively managed by turning and watering it regularly, the process of decomposing into finished compost can happen in as little as two to three weeks (otherwise, it may take months).
The compost conditions must be balanced for efficient decomposition. There must be:
- Plenty of air – mixture should be turned daily or every other day
- Adequate water – mixture should be moist, but not soaking wet
- Proper mix of carbon to nitrogen – ratio should be about 30:1 (see Elements of Composting: C:N ratio and Virtual Pile for details)
- Small particle size – big pieces should be broken up, as smaller particles break down more rapidly
- Adequate amount of soil – should provide enough microorganisms for the process
The major goal of composting is to reduce the amount of solid waste you generate. If you reduce solid waste, you will save space in municipal landfills, which will ultimately save you tax money. Finished compost has the advantage of being a useful natural fertilizer that is more environmentally friendly than synthetic fertilizers.
The compost pile actually has a complex organization of living organisms — a foodweb. Bacteria and fungi primarily break down the organic matter in the trash. Single-celled organisms (protozoa), small worms (nematodes), and mites feed on the bacteria and fungi. Predatory nematodes, predatory mites and other invertebrates (sowbugs, millipedes, beetles) feed on the protozoa, mites and nematodes. All of these organisms work to balance the population of organisms within the compost, which increases the efficiency of the entire process.
What is a compost heap?
A compost heap is a mound of decaying organic matter used by gardeners to re-cycle garden waste into a free organic soil improver and plant feed. A compost heap may be a simple pile in the open but may also be enclosed in a brick or wooden structure to keep the heap tidy and to help conserve heat which helps in the composting process.
Smaller plastic static or rotating compost bins can be used urban gardens where insufficient waste is produced to fill a large compost bin.
To build a compost heap add a mix of organic matter consisting of green material rich in nitrogen and brown material rich in carbon. The mix is approx 50/50 and is important as too much green material results in a soggy and often smelly heap while too much brown material remains dry and will take a very long time to break down.
Heap style compost bins,whether enclosed in timber, brick or block may take a long time to break down unless efforts are made to conserve heat in the pile. Adding an insulating material like old carpet can help retain heat and speed up decomposition. The advantage of a hot compost pile over a cool one is the temperatures (up to 75 degrees C) will kill off any weed seeds or pathogens which would otherwise be spread on you garden.
The fastest and most effective compost system for kitchen waste is an insulated tumbler type bin which can compost very quickly. Insulated tumblers like the Joraform JK125 and JK270 have a number of advantages over traditional systems including the ability to deal with cooked food (including meat and fish) and to create an even heat through the pile. The compost drum is rotated after fresh material is added which mixes the compost and adds air to the material. The insulated steel hopper is rodent proof and easily reaches the high temperatures for quick composting and a weed and pathogen free compost.
The raw materials that go into compost come from organic waste. These green, organic disposables can come from your garden, your kitchen, and even your home at large (see Coffee Grounds and Compost). The more of it you keep from the trash, the more you keep from landfills. According to the United States EPA, yard trimmings and food residuals together constitute 20-30 percent of the U.S. municipal solid waste stream. That’s a lot of waste to send to landfills when it could become beneficial, environmentally sound compost instead!
Efficient and easy to use! The composting bins and supplies available at Planet Natural will reward you with piles of rich organic matter to use in your yard, garden, or houseplants.
The best thing about making your own compost is that you can control what goes in it and keep the harmful stuff out (see Can you Compost Tomatoes?). You control the balance of ingredients and don’t rely on any one component, say the ubiquitous “forest products” that make up so many commercial grades of compost.
A variety of ingredients — brown and green — are needed in the pile. The more varied the materials in your compost, the richer the finished product, filled with micro-nutrients and diverse, beneficial microbial life, will be. Here’s our list with special considerations and no-nos:
- Grass clippings
- Brush trimmings
- Manure (preferably organic)
- Any non-animal food scraps: fruits, vegetables, peelings, bread, cereal, coffee grounds and filters, tea leaves and tea bags (preferably minus the staples)
- Old wine
- Pet bedding from herbivores ONLY — rabbits, hamsters, etc.
- Dry cat or dog food
- Dust from sweeping and vacuuming
- Dryer lint
- Old herbs and spices
Need Prep or Special Time
All of these items can be added to compost, but if you just toss them into a normal heap, they may still be there, virtually unchanged, a season or two later. Be prepared.
- Shredded newspaper, receipts, paper bags, etc (any non-glossy paper)
- Tissues, paper toweling, and cotton balls — unless soaked with bacon fat, kerosene, makeup, or other stuff that doesn’t belong in the pile!
- Cardboard, egg cartons, toilet rolls
- Used clothes, towels, and sheets made from natural fabrics — cotton, linen, silk, wool, bamboo
- Old string & twine made of natural fabrics
- Pine needles
- Pine cones
- Saw dust
- Wood chips
- Nut shells
- Hair, human or otherwise
- Old, dry pasta
- Nut shells
- Corn cobs
- Pits from mangos, avocados, peaches, plums, etc.
- Toothpicks, wine corks
- Raspberry & blackberry brambles
- Long twigs or big branches
- Pet droppings, especially dogs & cats
- Animal products — meat, bones, butter, milk, fish skins
Composting Grass Clippings
Grass trimmings are the quintessential compost ingredient. But more than one composter has discovered, to his distress, that the grass he dumped into his compost pile, instead of decaying into a nice, dark, crumbly, humus-rich compost, has instead putrefied into a slimy, stinky mess.
Grass does indeed make a fine feed-stock for compost, but it easily compacts into an oxygen-free mat. Since it contains a high percentage of water (over 50%), it swiftly goes anaerobic in the absence of oxygen. To prevent this, it should be mixed with other ingredients in the bin or with soil or even sawdust before it’s added to the pile. At the very least, spread the grass out over the top of the pile.
Sawdust, wood chips, sticks and twigs (best shredded or chopped), and pine needles can be added to compost, but be aware that their carbon content is very high. They will require a long time and/or a lot of nitrogen to break down. Use them in only moderate amounts, and add them in thin layers or mix them in with other ingredients, so the maximum surface area will be exposed to air and to microbes. Sawdust, like grass clippings, tends to form dense, anaerobic clumps that resist composting, so this material, in particular, should only be sprinkled into a compost heap in thin layers.
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Tip: Consider throwing some mineral-rich algae, kelp meal or lake weed into the pile. Just be sure to rinse off any salt water before adding. Also, you may want to add ashes from a wood-burning stove if you’ve added a lot of acidic materials such as pine needles and oak leaves. Wood ashes are alkaline and can help adjust the pH of your compost pile if it gets too acidic.
From the Kitchen
Your kitchen can make a significant contribution. Fruit or vegetable trimmings, rather than going down garbage disposals and into the sewer system or septic tank, make excellent compost additions. Breads, cereals, hamburger buns, old oats whether quick or slow, rolled or cracked — in fact, grains of any kind or condition are fine. Coffee grounds add nitrogen, and tea is fine; toss them in with their bags or filters (unbleached coffee filters are preferable and the staples in tea bags can be troublesome). Prepared foods, excluding meats (unless you’re using an aerobic digester), can be composted but can make your heap harder to manage for odor and moisture content. Their presence in outdoor piles can attract pests. If you maintain a hot pile or bin, items including old ketchup, relish, soy sauce, and such are acceptable but only in moderation. They’re quite acidic and could play havoc with the pH balance in the bin if added in excess. A long list of other things — nut shells, egg shells, corn cobs and so on — can also be composted; they’ll just take a while to break down.
Materials to Avoid
Coal Ash – Most ashes are safe to mix into your compost pile, but coal ashes are not. They contain sulfur and iron in amounts high enough to damage plants.
Colored Paper – Some paper with colored inks (including newsprint) contain heavy metals or other toxic materials and should not be added to the compost pile.
Diseased Plants – It takes an efficient composting system and ideal conditions (extreme heat) to destroy many plant diseases. If the disease organisms are not destroyed they can be spread later when the compost is applied. Avoid questionable plant materials.
Inorganic Materials – This stuff won’t break down and includes aluminum foil, glass, plastics and metals. Pressure-treated lumber should also be avoided because it’s been processed with chemicals that could prove toxic in compost.
Meat, Bones, Fish, Fats, Dairy – These products can “overheat” your compost pile (not to mention make it stinky and attract animals). They are best left to large-scale anaerobic digesters and avoided entirely (with certain exceptions) at home.
Pet Droppings – Dog or cat droppings contain several disease organisms and can make compost toxic to handle. (Can you believe the state of Alaska actually spent $25,000 on a study to determine the effects of composting dog poop? – PDF)
Synthetic Chemicals – Certain lawn and garden chemicals (herbicides – pesticides) can withstand the composting process and will remain in the finished compost. Don’t put anything recently sprayed in your compost heap.
Most contemporary pesticides break down quickly enough so that if they were used even six months earlier, foliage or grass from affected areas can be included in compost heaps. One important exception is Clopyralid, a pesticide which in 2003 was discovered to persist in soil far longer than had previously been realized. Fortunately, it is not harmful to humans or animals, but it can be quite toxic to a number of different vegetables. Since it passes unchanged through the composting process, composting foliage contaminated with it ensures that when the compost is spread, so will the Clopyralid be spread.
Note: Though compost has an extraordinary ability to break down pollutants and pesticides, it cannot handle the quantities sprayed on recently treated grass. Acre for acre, ten times as many pounds of pesticides are used on American lawns as are used on farmland. In other words, when pesticides are applied on turf grass — including homeowner’s lawns — they are generally applied at very high rates. This is good reason to encourage your community to reduce lawn and park spray programs . It’s also why grass clippings should not be composted if they have come from a lawn where pesticides were used recently.
Weed Seed, Diseased Plants and Other Contaminants
Whether it is safe to include weeds that have gone to seed, or tomato plants that have been infected by disease or nematodes, depends entirely on how hot your composting system is and how long you keep it hot.
Many experts advise not to put diseased plants or weeds that have gone to seed in compost piles. That’s the conservative fail-safe position. If you want to be absolutely sure that you won’t spread weeds when you spread compost, don’t put weed seeds in the pile (not always an easy task). The same goes for diseases.
However, a good, hot pile will kill just about every seed and every disease pathogen you can throw at it. Indeed, one major study (PDF) concluded that “For all of the bacterial plant pathogens and nematodes, the majority of fungal plant pathogens, and a number of plant viruses, a compost temperature of 131°F (55°C) for 21 days was sufficient for ensuring eradication.”
here are several exceptions. Two common tomato diseases, tomato wilt (caused by the fungus Fusarium oxysporum f. sp. lycopersici) and Tobacco Mosaic Virus (TMV), as well as clubroot of Brassicas (caused by the fungal pathogen Plasmodiophora brassicae), all required 21 days at 149°F (65°C) to degrade. Even this news is not quite as bad as it seems; TMV appears to degrade at lower temperatures if it is given sufficient time.
A Word About Activators
Compost activators add nitrogen, microorganisms, or both to your pile. They provide a quick boost to the decomposition process. Nitrogen sources include alfalfa meal, cottonseed meal, blood meal, or finished manure. Naturally occurring microorganisms get a boost from a reputable compost starter. They’re a probiotic for your pile.
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Expect rich, moist humus in 60-90 days! Ringer® Compost Plus contains a proprietary blend of microorganisms which break down yard waste as well as a nutrient energy source for a fast start. Specifically formulated to speed up the natural decomposition process for fast, complete composting.
Also, you may want to add ashes from a wood-burning stove if you’ve added a lot of acidic materials such as pine needles and oak leaves. Wood ashes are alkaline and can help adjust the pH of your compost pile if it gets too acidic.
Speeding Up the Compost Process
Compost decomposes fastest between 120 and 160˚F, so anything that will increase the heat will “cook” your compost faster. Here are four tips for fast composting:
- Chop and shred larger items, which makes it easier for the bacteria to break them down. For example, one easy way is to slice and dice garden waste is to run your lawn mower over leaves and other garden waste. Take scissors to newsprint or cardboard.
- Turn, turn, turn.
- Give your compost heap a “big meal” versus small snacks. Collect all your organic waste over a couple of days and then add it in one big bunch. The more you add at one time, the more your compost will heat up.
- Keep your compost pile in the sun. The heat will speed up the process
When is Compost Finished?
The last stage of composting is called ‘curing’. This is when the pile is set aside, not added to or turned, the temperature will lower to finish the process.
Curing can take anywhere from 1 month to 1 year. Many composters have their own preferences as to how long to cure a pile. Some will intentionally wait over a year to ensure higher quality compost, and others will use a shorter process because they need to make space for new piles.
There are a few ways to tell if your compost is ready to use:
- 1 It looks like dark, crumbly topsoil
- 2 It has a pleasant, earthy odor. It should not smell like ammonia
- 3 The original organic materials (with a few exceptions) should no longer be recognizable
- 4 The compost pile should have shrunk by half the size
- 5 The pile should have returned to air temperature, about 50 degrees F
While the majority of organic materials should not be recognizable in finished compost, it’s okay if there are a few stubborn materials, such as corncobs or wood chips that do not decompose. These materials should not be used in the finished compost, though – they should be filtered out by a process called ‘screening’.
Screening passes the finished compost through a filter. Objects that are larger than the filter can be added to a new compost pile. They can be beneficial to a new compost pile because they contain microorganisms that will help jump-start the composting process.
One simple way to test finished compost is to take a handful and put it in a sealed plastic bag. After 3 days, open the bag and smell. Does it smell sour? If so, the compost is not finished curing and still has microorganisms at work. If it smells pleasant and earthy, it’s ready to use.
There are also a number of composting tests using plant germination that you can use to see if your compost is safe to use with plants.
Beyond your own testing, compost can be approved by third party organizations. If you are selling your compost these tests may be required by the retailer.
A widely used and respected program for compost quality testing is The US Composting Council’s Seal of Testing Assurance program.
Below are factors that affect the quality of compost:
- Time to Mature
Compost that has been allowed to cure, or mature, is healthier for soil than immature compost. Immature compost may contain plant inhibitors, such as bacteria that will compete with the plants for nitrogen in the soil. You will want to test the compost for maturity to make sure it is safe to use.
- Source Materials
The materials added to the compost pile will affect the nutrients, soluble salts, and contaminants found in the soil. Compost made from food scraps is typically higher in nutrients, but also higher in soluble salts (which are harmful to plant growth).
- Hot vs. Cold Composting
Cold compost is likely to have more nutrients than hot compost; however, hot compost is less likely to have pathogens and weed seeds.
Compost Tea Bags
Compost is ready or finished when it looks, feels and smells like rich, dark earth rather than rotting vegetables. In other words, it should be dark brown, crumbly and smell like earth. The Florida Online Composting Center is one of the few sites that offers detailed home tests for the maturity of compost. The Ohio State University Extension Office has a much more detailed and technical site on testing compost; while some tests described there would only be appropriate for a large-scale operation, much of the information and a few of the tests are useful for back-yard composters as well. Beyond its practical uses, the Ohio site helps composters understand the many criteria involved in assessing compost maturity, from pH to microbial activity to temperature.
A potent elixir for your garden! Compost tea nourishes plants quickly without danger of burning. Rich and balanced in nutrients, this precious liquid give plants a boost, stimulating growth and giving them the strength they need to ward off pests and disease.
The Importance of Mature Compost
Immature compost may contain substances damaging to plants, including acids and pathogens. Furthermore, immature compost in soil continues to decay, a process requiring both nitrogen and oxygen. When these elements are being used to degrade organic material, they’re unavailable to plants. For all of these reasons, it’s important that compost be thoroughly mature before it is applied to soil.
If you have a hot pile that’s been turned regularly, knowing when it’s done is easy: it won’t heat up any more, even after being turned. Wait several weeks for it to cure, and it’s done.
That extra time for curing allows the microbes that operate at lower-temperature to put their finishing touches on the pile. It also allows earthworms and other larger organisms which don’t tolerate high heat to move back into the compost. This is a bit like having your cake and eating it too: they improve the compost itself and then they improve the soil where the compost is added.
With cool piles, the line between mature and unfinished compost isn’t as easily marked. Knowing when it’s done takes a combination of experience and artistry. After a year, most cool piles are ready to be used.
In completely finished compost made from shredded materials, none of the original ingredients will be recognizable. If you don’t shred ingredients, however, this would probably take years, since egg-shells, peanut shells, twigs, wood chips, avocado pits and other items take much longer to degrade than do apple cores, moldy bits of bread and tea bags.
Since finished compost can, in fact, contain such things, the important test for whether cool compost is done is the first one given: the look, feel, and smell of it. Mature compost does not contain slimy things, for instance, nor should ordinary kitchen vegetables (carrots, corn, peppers) be recognizable. Garden refuse, too, should be unrecognizable, save for the occasional woody stem or autumn leaf. If pea or bean plants or leafy hedge trimmings can still be picked out and named, the compost needs more time.
So — what should one do with those egg-shells, wood-chips, and so on? There are several ways to deal with such recalcitrant, woody items, known as “wood-overs” or “compost-overs” or simply “overs” — the over-size pieces that won’t fit through about a half-inch wire mesh or hardware cloth.
You can use the compost as is with the overs in it, pick the biggest pieces (the avocado pits and corn cobs) out by hand, or screen the entire batch, returning the bigger bits to the active compost pile for another round. If you do remove the overs and return them to the pile, they take with them the composting micro-organisms that adhere to them which give a boost to the fresh compost.
The first option is to ignore them. Just use the compost as is, even with the occasional recognizable peanut or egg shell. These things will decay in your soil, though it’s true that the process requires a certain amount of nitrogen. It’s therefore not recommended to add compost with high proportion of uncomposted refuse to nitrogen-poor soil. In general, if you spread such compost in the fall, many of these bigger pieces will break down over the winter.
Alternatively, you can pick the biggest offenders — the corn cobs and avocado pits — out of the finished compost and toss them back into the active pile for another go-round. This can be done easily with things as large as corn cobs, but if you find yourself picking through the compost to find individual peanut shells, it is time to set up a screen. Even avocado pits will compost over a couple of seasons, turning at last to a soft, reddish pulp.
Screening compost takes time and a certain amount of energy but it results in a gorgeous, light and uniform soil. A compost screen can be purchased or built from a few boards and a square of wire netting and set directly over a wheelbarrow, though the wheelbarrow may need to be set up on cement blocks to bring it to a comfortable working height for some folks. This arrangement makes for the least amount of shoveling as the compost comes out of the bin straight onto the screen. It’s then ready to wheel off to the flower border, the potato bed or the raspberry patch.
The composting process
Microorganisms are vital to the composting process and are found everywhere in the environment, said Matthew Worsham, the sustainability and energy coordinator at the University of Dayton in Ohio.
The key to effective composting is to create an ideal environment for the microorganisms to thrive, Worsham told Live Science — warm temperatures, nutrients, moisture and plenty of oxygen.
According to Cornell University, there are three main stages in the composting cycle in which different types of microorganisms thrive.
The first stage is typically only a couple of days long during which mesophilic microorganisms, or microorganisms that thrive in temperatures of about 68 to 113 degrees Fahrenheit (20 to 45 degrees Celsius), begin physically breaking down the biodegradable compounds. Heat is a natural byproduct of this initial process and temperatures quickly rise to over 104 degrees F (40 degrees C).
Mesophilic microorganisms are replaced by thermophilic microorganisms (microorganisms that thrive in the increased temperatures) during the second stage, which can last from a few days to several months. The thermophilic microbes work to break down the organic materials into finer pieces. The higher temperatures are more conducive to breaking down proteins, fats and complex carbohydrates.
Also, during the second stage, temperatures continue to rise and if not closely watched, the compost pile can get so hot that it can eventually kill off all the helpful microorganisms. Techniques such as aeration and turning over the compost pile help keep temperatures below about 149 degrees F (65 degrees C), as well as provide additional oxygen and new sources for the thermophilic microorganisms to break down.
The third stage, which typically lasts for several months, begins when the thermophilic microorganisms use up the available supply of the compounds. At this stage, temperatures begin to drop enough for mesophilic microorganisms to resume control of the compost pile and finish breaking down the remaining organic matter into usable humus.
The organisms that help
There are two main classes of composting microorganisms, known as aerobes and anaerobes, according to Planet Natural.
The aerobes are bacteria that require oxygen levels of at least 5 percent to survive and are the most important and efficient composting microorganisms, according to the University of Illinois. The aerobes consume the organic waste and excrete chemicals such as nitrogen, phosphorus and magnesium, which are nutrients plants need to thrive.
Anaerobic microorganisms are bacteria that don’t require oxygen. They also don’t process the organic waste as efficiently as aerobic bacteria. Anaeorbs produce chemicals that are occasionally toxic to plants, and they cause composting piles to stink because they release hydrogen sulfide, which smells like rotten eggs.
About 80 to 90 percent of all microorganisms found in compost piles are bacteria, according to Cornell University. The remaining percentage of microorganisms are species of fungi, including molds and yeasts.
In addition to microorganisms, other helpful creatures, such as pill bugs, centipedes and worms, will find their way to the composting pile if the conditions are right. These animals break down the food waste, yard trimmings and other organics in the compost pile and help turn the waste material into nutrient-rich soil.
Worsham is building composting resources at the University of Dayton and is including red wiggler worms in the composting piles. Red wigglers (Eisenia fetida) are the most common worm used in vermicomposting, or composting with worms, Worsham said. The university’s vermicomposting piles can break down 10 pounds of food waste and paper per day.
What does and doesn’t go in?
According to the United States Environmental Protection Agency, a balance of “greens” and “browns” is needed to create the proper environment for composting to occur. Greens are nitrogen-rich, and include items such as grass clippings, fruit and vegetable waste, and coffee grounds. Browns are the carbon-rich yard clippings, such as dead leaves, branches and twigs.
A carbon-to-nitrogen ratio between 25 to 1 and 30 to 1 is ideal for rapid composting, according to the University of Illinois. Microorganisms feed on both carbon and nitrogen. The carbon gives the microorganisms energy, much of which is released as carbon dioxide and heat, and the nitrogen provides additional nutrition to continue growing and reproducing.
If there is too much carbon in the compost pile, decomposition occurs at a much slower rate as less heat is generated due to the microorganisms not being able to grow and reproduce as readily, and therefore not able to break down the carbon as readily. On the other hand, an excess of nitrogen can lead to an off-putting ammonia smell and can increase the acidity of the compost pile, which can be toxic for some species of microorganisms.
Proper moisture is also vital for the health of the microorganisms that help with the composting process. A moisture content between 40 and 60 percent provides enough dampness to prevent the microorganisms from becoming dormant but not enough so that oxygen is forced out of the pile.
The amount of oxygen within the compost pile is also important as an oxygen deficit leads to anaerobic microorganisms taking over, and that can lead to a stinky compost pile. Oxygen can be added into the compost pile by stirring or turning over the pile.
What to compost:
- Fruits and vegetables
- Coffee grounds and filters
- Tea bags
- Nut shells
- Shredded newspaper, paper and cardboard
- Yard trimmings including grass, leaves, branches, and twigs
- Hay and straw
- Cotton and wool rags
- Dryer and vacuum cleaner lint
- Hair and fur
- Fireplace ashes
(Note: The USDA recommends burying food waste if using an open-composting pile to deter unwanted pests looking for a free meal, such as flies, rodents and raccoons.)
What not to compost:
- Certain types of tree leaves and twigs such as black walnut, as it releases substances that may be harmful to plants
- Coal or coal ash, as they might contain substances that are harmful to plants
- Dairy products, eggs, fats and oils, and meat or fish bones and scraps, due to potential odor problems that attract pests such as rodents and flies
- Diseased or insect-infested plants, as the disease or insects may survive and be passed along to other plants
- Pet waste (including dog and cat feces and used cat litter), as it might contain harmful parasites, bacteria or viruses
- Yard trimmings treated with chemical pesticides; as the pesticides might kill composting organisms
Commercial composting companies also collect products such as paper carry-out containers for food and compostable dinnerware and flatware that are specifically labeled BPI Certified Compostable.
Dairy products, eggs, meat products and fats are typically not recommended for the composting pile, but there are many larger commercial composting facilities that are well-suited for dealing with the smells and pathogens that may exist in these products.
To help with the more complex waste, livestock manure is often added to commercial composting sites to help increase the heat and the rate of composting. According to North Dakota State University, livestock manure from herbivores, including cows, sheep and goats, already contains a high amount of nitrogen and many of the aerobic microorganisms that are essential to composting. This type of manure is also typically free of dangerous pathogens that can be found in the manure of meat-eating animals, such as cats and dogs.
Composting helps accelerate the natural decomposition process of organic materials. (Image credit: )
What else can be composted?
Many companies are developing more products that can be composted when disposed of, including dinner and flatware, garbage bags and even diapers. Before putting these items in the compost pile, it is important to make sure they are safe to compost at home or accepted by the local compost collector.
Huantian Cao, professor of fashion and apparel studies at the University of Delaware, co-directs a sustainable apparel project that’s working on developing compostable apparel. Cao and his team have developed a shoe that is essentially made of mushrooms.
The prototype sandal is made from a variety of compostable parts, Cao told Live Science. The midsole is made from a mushroom mycelium composite that can go right into a home composter along with all the food scraps. The insole and outsole of the shoe are made with biodegradable vegetable-tanned leather and the straps of the sandal are made with cotton, both of which can be composted at larger, commercial composting sites.
Composting at home
Randi Cox and Kathy Gutowsky, owners of the commercial composting company, Green Camino, have been composting since they were young and now educate their community about the benefits of composting, whether through use of their company or at home.
“Composting is an entryway drug to zero waste,” Gutowsky said. “As you start composting, you are really starting to pay attention to what you are throwing away and you start to look at what you are buying and what is coming in.”
Gutowsky said that many of their clients make lifestyle changes to minimize what goes in their waste bins, including not buying products with excess plastic packaging and buying locally when possible. “It’s really a mindset shift,” Gutowsky told Live Science.
If you don’t have access to a commercial composting site, getting started at home is as easy as putting together a pile in the corner of your yard. Many hardware stores sell composting bins of various types and sizes to accommodate each home’s need. Be sure to check regulations on composting where you live by visiting your city or county waste department web page. Additional help getting started or any questions you may have can often be answered at your local hardware store, nursery or local farmer’s markets.