How to make compost tea

Compost tea is the perfect way to boost your plants growth and obtain higher yields – NATURALLY.

Better yet, you can make it for free using your own compost! We keep our garden productive year after year by following a simple and organic three prong approach.

We use compost (composting 101) and cover crops (planting cover crops) for building great soil structure and vitality – AND we boost plants during the growing season with a simple homemade natural liquid fertilizer on our plants called compost tea.

All you need to make your own compost tea is a couple of shove fulls of compost, A 5 gallon bucket and water

Compost tea or “black liquid gold” is the all organic “miracle-growing” solution to fertilizing the garden – minus the chemicals and high salt content that commercial fertilizers add to your soil.

It works its magic in two ways – feeding your plants through the roots (soil zones around plants) and the leaves (foliar zones). Unlike synthetic fertilizers, it won’t build up chemicals and salt levels that can slowly destroy your soil structure.

Instead, adding nutrients that build it!

If you follow along with our blog, you know how important compost is in building healthy soil.

We add large amounts of compost to all of our planting beds each year, as well as a good shovel full in every single planting hole.

Well, that compost, made from our decomposed vegetable scraps, chicken manure, grass clippings, coffee grounds, and more – is teeming with all-natural, plant-boosting nutrients.

By converting those nutrients into a liquid form – we can utilize those nutrients as an organic fertilizer to naturally boost plants growth through the growing season.

How we use it:

Compost tea works through absorption via the leaves and soil

Compost Tea can be applied about every two weeks to your garden plants once plants and transplants have become established. By established, we simply mean that they have been in the ground 7 to 10 days and are over the initial shock of transplant.

We apply ours with a watering can or a simple garden sprayer – soaking the area around the root base and the leaves of each plant with the solution.

The minerals and nutrients are then absorbed through the leaves (foliar absorption) as well as through the root zone – doubling the effect. As with watering, it is best to apply early in the day before the sun is too hot and the tea can burn the leaves of plants.

We repeat the compost tea applications every two weeks until about mid July.

Why stop? Too much of a good thing can also be bad. You want plants to develop strong roots and stems – but too much and the plant will spend all of its energy creating thick foliage and not much fruit.

Start by filling a clean bucket 1/3 full of compost

We have found that 4 to 6 total applications seem to be the perfect mix for giving plants the boost they need for good higher yields.

The best part – its 100% natural, with no fear of having to use any chemicals in your garden.

How we Compost Tea

There are many ways to make compost tea – but we have found this method to be easy, effective, and most importantly, simple!


Let the mixture steep for 5 to 7 days, stirring a few times each day.

You will need a 5 Gallon Bucket, stir stick, water, and a few shovel fulls of finished compost.

Start by filling your bucket about 1/3 full of compost. Use compost from the bottom of your pile, where organic matter has decayed the most and is teeming with life.

Next – fill the bucket to the within an inch or two of the top with water. It is best to use well water (we use our rain water) because there will be no chlorine or other chemicals.

Chlorine can kill off many of the helpful bacteria and organisms that are alive in compost. If you only have access to city water, no worries – simply fill the bucket a few days in advance and let sit outside.

The sun and air will work its magic and within a few days, almost all of the chlorine will be gone.

Strain and you are ready to use!

Stir the compost good with a stick or the end of your garden shovel. Over the course of the next 5 to 7 days, stir the bucket a few times each day.

This aeration of the water and the stirring of the compost helps to release more nutrients into the water, much like dunking a tea bag releases more tea into your drink.

At the end of 5 to 7 days, simply strain the mixture through a piece of burlap, mesh screen or our preferred method – using a strainer.

We have a dedicated strainer that we use a 5 quart Stainless Steel Strainer that fits perfectly over the 5 gallon bucket. And then you are left with the magical liquid gold fertilizer called compost tea!

Store in an air tight container to keep the “liquid gold” at it’s best nutrient levels.

Bonus Info:

You can get a little more fancy in your compost tea making if you desire.

It has been shown that adding a simple aquarium pump to the bucket and letting it run to percolate the mixture will increase the potency of the finished mixture, and can be completed in as little as 2 days.

Others also add molasses or sugar to the mixture to increase the absorption of the water and organisms.

Although not appetizing to drink -compost tea is great for your plants!

However, for us, the simple bucket and stirring method has certainly worked wonders for our garden. Besides, the extra few days we let ours steep in the water is worth not having to go through the trouble of setting up a pump, wires, etc. For us, keeping it simple is the key!

So how about trying your own liquid gold this year and get those plants growing big and strong!

Happy Gardening – Jim and Mary

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Compost Tea – How To Make And Use The Ultimate Organic Fertilizer Tagged on: Compost Compost Tea composting how to make compost how to make compost tea natural fertilizer organic fertilizer organic gardening

What is compost tea (and how do you make it)?

As with everything, there is controversy around how to make compost tea.

The two basic camps are anaerobic, or aerobic, and there is ‘scientific research’ to back up both sides that you can easily find on Google. The aerobic method ‘brews’ beneficial bacteria with added oxygen, introduced by something like an aquarium pump, creating an environment that favours bacteria that require oxygen. Anaerobic is the opposite – you put the lid on, and keep the air out.

After reading way too much on this topic, we invested in some supplies to start making the aerobic kind of compost tea. Two books have really started to reframe my mental approach to yardening, Masanobu Fukuoka’s classic The One Straw Revolution, and the more recently released Teaming with Microbes.

I’m now beginning to understand why people are making such a fuss about till versus no-till, and the negative impact to your soil life even from something as simple as a basic chemical fertiliser. As an aside, this guy gets into my Hall of Fame for doing no-till in an old refrigerator!

Aerated Compost Tea

Brewing compost tea aerobically increases the number of beneficial bacteria and other microbes, which results in naturally healthy plants with good yield. Most importantly it creates or strengthens a soil web of life that controls disease and creates its own fertiliser for the plants.

Some people swear by it, some people say it doesn’t work at all, and one guy said it killed some of his plants! My advice is to test some on your plants first just in case. We are having positive results already and have not seen any plant mortality. The most positive results so far have been controlling a powdery mildew (or something that looks like it) and some big plant growth.

My actively aerated compost tea brewing kit cost under $20, but you can probably do it for less. I couldn’t find an aquarium pump at my local pet store or garage sale so I bought a new one from Amazon because I had a credit there. I bought a two outlet air pump, 10 feet of plastic tube and two ‘air stones’. I also got a five gallon plastic bucket from the garden area and a big rock to hold the air stone down. Here are the pics of the Tea Pot, and some white plant disease we are trying to kill.

Editor’s note: The capacity of the air pump is important. 1/2 to 1 x the air, in relation to the capacity of the container (fluid).

Becoming a compost tea brewer

You will also need:

  • A couple of cups of compost – I use worm castings from my giant worm bin.
  • Water with no chlorine. Let your bucket of water sit out in the sun for a couple days and you should be fine. I use a 5 gallon bucket which needs 4 gallons of water.
  • A source of sugar. Most sites recommend molasses because of the additional nutrients available to the microbes. I’m using white table sugar, which works just dandy for other bacteria like Kombucha and seems to work fine for this. I use a tablespoon per gallon.

Making compost tea

Take your bucket of water and turn on the air pump. Mix the compost and the sugar and add it to the water. I let mine run for about two days. It should have a sweet soil smell and it will produce foam and bubbles. When it’s done you can use it as a soil drench or a foliar (leaf) spray. I do both. I also water it down a lot but I’ve also put it on the plants straight.

Every article and book I read reports different ways to do brew compost tea. Recipes can be for bacterial dominant tea or fungal dominant tea. Didn’t know this would be so darned complicated, eh? Here are some articles to give you a well rounded approach to investigating and experimenting:

  • Compost Junkie
  • Dirt Doctor
  • Captain Compost

Don’t run the aeration pump too long or the bacteria run out of food and start to go dormant. Don’t do it without oxygen or you grow bad bacteria (apparently). If you add other stuff, like fish emulsion, then something else happens but I don’t remember what!

I’m trying to keep it simple: sugar and oxygen feed good bacteria that promote balanced healthy soil. Give it a go – and report back to me!

Editor’s note: The bacteria need a nutrient source. Liquid seaweed is normal, but nettle/comfrey juice works too. If the brew becomes anaerobic, there are compounds produced that may be harmful to plants. Composts that derive from animal manures may be an e coli/salmonella risk if the aeration is not good enough. Important if you are spraying salads, or selling produce. As far as I am aware, they are both facultive anaerobes.

This post originally appeared on Brad’s brilliant

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Actively Aerated Compost Teas (AACTs)

Rocky Mountain Organic Supply Tea Recipe Click Here!

Actively Aerated Compost Teas are an integral part of any organic gardeners growing regiment. AACT is the process of taking very high quality compost, vermicompost or worm castings and growing the microbial populations in that material hundreds of thousands of times to millions of times through the process of brewing with clean aerated water and microbial foods. Once the brew is finished you have a liquid soil or foliar inoculant bursting with healthy microbiology that goes right to work in replenishing or helping correct a deficiency present in your current soil food web, or helping any foliar issues you may be having.

Download our basic starter recipes for tea brewing and what we recommend after years of working with teas and lots of PhD backed research.

Download Our Tea Recipe

As you become more comfortable with brewing teas you can expand upon these recommendations but ideally you would do so only after learning how to identify organisms under a microscope to ensure what you are brewing up is healthy and not filled with bad soil food web microbes. By sticking to our recommendations you will be very successful in this endeavor and your gardens and lawns will thank you many times over through less water usage and disease resistance. Using teas can help revitalize dirt and turn it into productive soil!

Items needed – Most of these items can be bought at your local Hydroponics shop or pet store, so the links below are to give you an idea of what you need to get. If you would rather buy off the internet you can find these items through Amazon or other retailers.

Brewing container – This can be as simple as a pitcher or even a 5 gallon bucket from the hardware store. This can also go as large as you need, scaling isn’t an issue, it just takes different equipment. Lots of people start small with a 5 gallon bucket and eventually graduate into many 5 gallon buckets or even trash cans or 55 gallon drums. You want to make sure to thoroughly clean this container after each brew as you don’t want to have bad guys take up home in a dirty container for the next tea brew.

Air pump – This is what brings oxygen into the water and will make sure all of the good microbial populations have plenty of oxygen to grow with and survive on. You want to make sure you choose the appropriate pump for the application you will be doing. If you are looking to only do 1 pitcher of tea at a time you only need a very small air pump, if you will be doing larger batches you need to make sure you have a large enough air pump to handle the larger population of microbes you will be brewing up. If you do not have a large enough air pump as the microbiology grows it will consume all of the available oxygen faster than it is being produced and dissolved into the water which will turn the tea from aerobic (with oxygen) into anaerobic (without oxygen). Anaerobic teas are not good and will spread bad organisms into your soil and onto your plants. There are some anaerobic teas we do make for special conditions, but when an AACT becomes anaerobic it is never good.

Smaller air pumps:

  • Supreme Aqua-Mag Aqua-Supreme Air pump 3 Watt
  • Active Aqua Air Pump, 2 Outlets, 3W, 7.8 L/min

Larger air pumps:

  • EcoPlus 793 GPH (3000 LPH, 18W) Commercial Air Pump w/ 6 Valves | Aquarium, Fish Tank, Fountain, Pond, Hydroponics
  • Active Aqua Commercial Air Pump, 6 Outlets, 20W, 45 L/min

Air stone or Dewey Mister

This is what diffuses the oxygen from the air pump into the water. Depending on the size of tea you are brewing will dictate the number of air stones you will need or Dewey Misters. These will also need to be cleaned after each brew to ensure bad microbes don’t take up home in your brewing equipment. For smaller brews (pitchers up to 5 gallon buckets) air stones can work great, bigger stones are needed for a 5 gallon bucket as opposed to smaller buckets and pitchers, or you can use multiple stones if the air pump you have has multiple outputs. For larger brews starting at 5 gallons and on up you will want to move to the Dewey Misters in most cases as they are easy to clean and do a wonderful job of aeration. You need a much larger air pump to run the Dewey Misters.

Air stones:

  • Shop for Air Stones

Dewey Misters:

  • Shop for Dewey Misters – Currently Sold Out

Air pump tubing – This is not usually included with the air pumps or the air stones and is required to tube from the air pump which sits outside of the brewing container to the air stone or Dewey Misters. You need 6mm/0.23” external diameter tubing (4mm/0.16” internal diameter).

Air tubing:

  • 6mm/4mm Translucent Silicone Flexible Airline Tubing for Aquariums Fish Tanks (25 Feet)
  • Deep Blue Professional ADB12296 Silicone Air Tubing for Aquarium, (Assorted Colors)
  • Elite Silicone Airline Tubing for Aquarium, 10-Feet, Blue

Clean water – One of the most important elements is having water that isn’t loaded with chlorine or chloramine (the new stronger chlorine they are adding to almost all city waters). Traditionally you only had to bubble water for 24 hours to make sure all of the chlorine is gone so it doesn’t kill off the microbiology you are trying to grow, now most cities are having to put chloramine in the water (call your local utilities company to inquire as to if they are adding this in). If you have chloramine in your water it will not leave through evaporation like chlorine, rather you must first bubble the water to get rid of the chlorine just like before but now you must also mix in an acid source such as lemon juice, lime juice or humic acid to remove the chloramine. You will add ¼ teaspoon of your chosen acid source per gallon of water and mix thoroughly to neutralize the chloramine.

***NEVER USE – Blackstrap molasses***

If you do some of your own reading online about compost tea brewing one of the biggest things you will run across is the recommendation to use blackstrap molasses as the microbial food in the tea. This used to be widely accepted as a great way of brewing tea. The issue is that without a firm understanding of soil biology and what microbes look like under a microscope people actually brew up anaerobic teas the majority of the time with blackstrap molasses. This is why that happens even with an air pump — molasses is a simple sugar which feeds bacterial populations very quickly basically as junk food. As the bacterial populations grow they take over the entire tea and use up all the oxygen, this causes the tea to become anaerobic as soon as the ppm (parts per million) of dissolved oxygen drop below 8 (6ppm is the critical point). There are plenty of bacteria all over this planet and we really don’t need to brew up heavy bacterial teas, rather we want to brew up complex teas that have a huge variety of life in them, not only bacteria but also fungi, protozoa and nematodes. When you only feed simple sugars to the microbiology in the tea brewing process the bacteria will out multiply all the other good guys and take over the entire tea. We instead feed complex foods to the tea so the fungi, protozoa and nematodes have a chance to grow and multiply. If you really want to use molasses in your brewing it is highly advisable to also get yourself a microscope so you can monitor the tea and make sure you use it before it goes anaerobic. As that is not practical for most home gardeners your best bet is to follow our simple recipes for wonderful results.

Tea Ingredients: Recommendations on where to source ingredients if you cannot find them locally in any of the garden/hydroponic shops around your area.

  • Worm Castings
  • Kelp Meal
  • Alfalfa Meal
  • Fish Hydrolysate
  • Soft Rock Phosphate
  • Bat Guano
  • Fish Bone Meal
  • Humic Acid

How to brew your tea:

Once you have everything sourced and the water is chlorine and chloramine free it is as simple as putting the air stone or Dewey Mister into the water and adding in the appropriate amount of ingredients each tea calls for. You can put them into a ‘tea bag’ like a nylon stocking or even a sock but it really is best to let everything free float in the water to get better surface coverage for the microbiology. Brew for the recommended amount of time and then water your plants either in the morning or evening, since the UV rays from the sun kill the microbiology – so you want to make sure the tea isn’t brewing in the sun or that you apply it during the heat of the day. During the summer you can brew outside in the shade perfectly fine. Once the temperatures start to fall you will want to move any brewing you do inside where there are more stable overnight temperatures.

How to use your tea:

You can dilute the tea down 1:1 (tea to clean water), but it works perfectly fine as a direct application. Teas can be applied several times a week for heavy feeding plants, but once a week is perfectly fine and even just a couple times a month during the growing season is helpful. If you plan on foliar spraying with teas make sure you strain it out so you won’t clog your sprayer. Never put teas into a metal watering can as the zinc inside the metal will kill the microbes! Make sure you use teas within 24 hours of brewing, ideally within 4 hours of the brew cycle finishing to ensure the highest microbial populations. If you make too much tea simply apply it to your compost pile. You can also use the left over tea sludge around the base of plants, or it works great in a compost pile.

Compost tea brewing is a rather simple process and we highly recommend it to anybody who is an organic gardener/landscaper. Contact us with any questions; we would be happy to help!

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