Fertilizer is basically a multivitamin for your plants.
It supplements the energy they’re getting from the sun and the soil, making sure they have everything they need to grow strong roots, lush leaves, and beautiful blooms.
If you’re looking for the best fertilizer for indoor plants, we’re here to help. There’s a lot to think about when it comes to choosing the right formula.
Here are some of the main things to think about while you shop.
- What Kind of Fertilizer is Best for Indoor Plants?
- The 10 Best Fertilizers for Indoor Plants
- Best Indoor Plant Fertilizer Reviews
- 1. Miracle-Gro 300157 Indoor Plant Food Spikes
- 2. Miracle-Gro Water Soluble All Purpose Plant Food
- 3. Osmocote Smart-Release Plant Food Plus Outdoor & Indoor
- 4. EarthPods Premium Indoor Plant Food
- 5. Jobe’s Organics 09524 Purpose Granular Fertilizer
- 6. Schultz All Purpose Plant Food
- 7. Jobes 5001T Houseplant Plant Food Spikes
- 8. JR Peters Jacks Classic All Purpose Fertilizer
- 9. Aquatic Arts Indoor Plant Fertilizer
- 10. Espoma Company INPF8 Organic Indoor Plant Food
- When to Fertilize Indoor Plants?
- How Often Should You Fertilize Indoor Plants?
- How to Fertilize Indoor Plants?
- UConn Home & Garden Education Center
- Houseplant Fertilization
- How to Care for House Plants
- Vitamins and minerals
- Soil life
- Worm compost
- How much to feed?
- Feeding Your Houseplants
- Liquid Fertilizer for Feeding Houseplants
- Feeding Sticks and Pills for Feeding Houseplants
- When Not to Feed Plants
What Kind of Fertilizer is Best for Indoor Plants?
There are a lot of different types of fertilizers to choose from which is one reason why it can be so tricky finding the right one for indoor plants. Here are a few different types to consider:
Liquid fertilizers are usually added to your watering can every time or every other time you water. Some formulas can be used for feeding your plants once or twice a month.
One of the best things about liquid fertilizer is you have a lot of control over how much is being applied. You can stop fertilizing during dormant periods and be confident that there isn’t any fertilizer still being released in the soil.
On the other hand, the downside is that you have to remember to add fertilizer to the water at the appropriate time which is easier said than done.
Granular fertilizers are mixed into the soil. They work especially well when you’re first potting a plant and can mix the granules throughout the pot.
Granules are a little tricky to use with indoor plants because they release all their nutrients at once when the plant is watered so it’s not easy to tell how much the plants are getting. Follow the directions on the package very carefully so you don’t over or under-feed your plant.
Slow-release fertilizers come in many forms, including spikes, pods, and capsules. They have a time-release coating that allows the nutrients to slowly make their way into the soil.
This type of fertilizer works better in small pots because you don’t have to worry about nutrient distribution as much since there’s less area to cover.
One of the downsides to slow-release fertilizers is that there’s no way of knowing how quickly the nutrients are dissolving. Ideally, the time-release shell is keeping it somewhat even but you never really know.
The 10 Best Fertilizers for Indoor Plants
There are a lot of options when choosing the right fertilizer for indoor plants. Here are some of the best options out there.
|Pictures||Indoor Plant Fertilizers||Fertilizer Analysis||Links|
|Miracle-Gro 300157 Indoor Plant Food Spikes||6-12-6|
|Miracle-Gro Water Soluble All Purpose Plant Food||24-8-16|
|Osmocote Smart-Release Plant Food Plus Outdoor & Indoor||15-9-12|
|EarthPods Premium Indoor Plant Food||2-2-4|
|Jobe’s Organics 09524 Purpose Granular Fertilizer||4-4-4|
|Schultz All Purpose Plant Food||10-15-10|
|Jobes 5001T Houseplant Plant Food Spikes||13-4-5|
|JR Peters Jacks Classic All Purpose Fertilizer||20-20-20|
|Aquatic Arts Indoor Plant Fertilizer||3-1-2|
|Espoma Company INPF8 Organic Indoor Plant Food||2-2-2|
Best Indoor Plant Fertilizer Reviews
1. Miracle-Gro 300157 Indoor Plant Food Spikes
These plant food spikes from Miracle-Gro are ideal for all indoor potted plants, including spider plants and ferns. Each spike is loaded with the micronutrients that your potted plants need and you can add more spikes as needed for larger plants.
One of the best things about this indoor plant fertilizer is how easy it is to use. All you have to do is poke a hole midway between the plant root stem and the rim of the pot. Then, push the spike into the soil until it’s covered.
Each spike works continuously for up to two months, though you should replace them every 30 days during the spring and summer when growth is more active.
2. Miracle-Gro Water Soluble All Purpose Plant Food
Miracle-Gro is one of the most well-known fertilizer brands so it’s no surprise to see another one of its products on our list. Rather than a spike, this product consists of water-soluble granules that you water into the soil.
When used as directed, this fertilizer won’t burn. It’s good for all plants, indoor and outdoor, so it’s a good choice if you have a lot of potted plants and want to give your outdoor plants some love, too.
This fertilizer should be applied once every one to two weeks for best results. It’s full of everything your plants need to give them the instant nutrition they need to grow strong and healthy.
3. Osmocote Smart-Release Plant Food Plus Outdoor & Indoor
Another option that’s great for indoor plants is this granular formula from Osmocote. Since it’s fortified with 11 essential nutrients, this fertilizer is very effective. You can use it on almost any plant in any growing condition, indoors or outdoors.
One of the best things about this product is that it feeds your plants for a full six months so you don’t have to worry about reapplying after a few weeks. When used as directed, it won’t burn or damage your plants.
Don’t worry – application is simple. Just use the included scoop to measure the right amount of fertilizer – one scoop for every two gallons or four square feet. Mix the granules into the top three inches of soil and water regularly. That’s it!
4. EarthPods Premium Indoor Plant Food
One of the most unique indoor plant fertilizers out there is EarthPods. This fertilizer comes in easy-to-use capsules, each containing concentrated organic plant food that stimulates root and stem development, improves leaf color and builds resistance against diseases.
One tube of this product contains 100 pre-measured pods – a five-year supply for a single houseplant. Not only is the tube easy to store, but it’s also 100% recyclable and made 100% sustainably made in the USA.
All you have to do is insert one of these pods near the center roots and water your plant. The pods break down slowly, releasing nutrients and trace minerals right to the roots. Use just one or two pods for small plants or up to eight for large ones.
5. Jobe’s Organics 09524 Purpose Granular Fertilizer
This is a great choice if you want an organic fertilizer that’s renewable, sustainable, and biodegradable. It’s certified for organic gardening and improves soil conditions to help your plants grow strong, resisting disease, drought, and insects.
Jobe’s Organics uses Biozome, a proprietary mix of fungi, healthy bacteria, and Archaea to help improve soil quality long term so your indoor plants can thrive. Either mix this in with potting soil before planting or add it to the dripline of existing plants.
This fertilizer comes in a large 16-pound bag so it’s a good choice if you’re repotting or adding new indoor plants to your collection and need a lot of fertilizer. The easy-pour bag can be resealed for safe and easy storage.
6. Schultz All Purpose Plant Food
If you prefer liquid fertilizer, take a look at this product from Schultz. Mixing this product is really easy – just add seven drops to each liter of water before regular watering. Or, you can feed your plants once or twice a month using 14 drops in a liter of water.
You can add this product when first planting, for maintenance, or when transplanting or repotting. This versatile formula is great for a variety of plants, too. Whether you’re growing an indoor herb garden or tending to orchids and cacti, this all-purpose formula is a good choice.
Each bottle in this two-pack contains eight ounces of fertilizer. Since you’re only using between seven and 14 drops at a time, this one can last a long time, depending on how many plants you have.
7. Jobes 5001T Houseplant Plant Food Spikes
Another option that’s really easy to apply is these plant food spikes from Jobes. They’re formulated for all indoor plants and provide continuous nutrition, right at the root for easy availability.
Each spike is pre-measured and formulated to be inserted directly into the soil. The size of the plant determines how many spikes you need. For example, for a four-inch pot, use two spikes. For a 12-inch pot, use six. To get the best results, reapply every eight weeks.
This double-pack comes with 50 spikes in all. That can last you a while, depending on how many plants you have. There’s no mixing or strong odor and it doesn’t leach out of the pot when you water.
8. JR Peters Jacks Classic All Purpose Fertilizer
This water-soluble fertilizer is evenly balanced to help your plants grow strong roots, stems, and leaves. Jack’s Classic uses enhanced micronutrients that are effective at any stage of plant growth.
There are two ways to use this product. You can dissolve it into the water for regular, routine care or use it as a periodic feed a few times a month. If you plan to use this fertilizer long term over a few months, alternating with plain water is best to avoid increased nitrogen or phosphorus in the soil.
This product can be applied to the roots or used as a leaf spray. Both methods are equally effective and easy to do. Follow the included instructions for the proper proportions when mixing.
9. Aquatic Arts Indoor Plant Fertilizer
This formula from Aquatic Arts is made specifically for house plants, whether in a pot, holder, or hanger. It promotes strong, healthy growth and prevents wilting more effectively than most pellets or granules.
Just use a teaspoon of this liquid in every two cups of water to give your plant the vitamins, nitrogen, and phosphorus it needs for better root, leaf, and bloom growth. This eight-ounce bottle lasts for up to a year, depending on how many plants you have.
We really like how versatile this fertilizer is, too. You can use it on just about any indoor plant, including poinsettias, orchids, African violets, cactus, air plants, mums, and Gerbera daisies.
10. Espoma Company INPF8 Organic Indoor Plant Food
Another easy-to-use liquid fertilizer is this formula from Espoma. It’s all-natural and organic and includes beneficial microbes to deliver the best results.
One of the things we like best about this product is how easy it is to measure and mix. All you have to do is shake the bottle well then turn it upside down, making sure the lid is secure. Then, turn the bottle upright, open the lid, and your pre-measured dose is ready to use.
All you have to do is thoroughly drench the soil and let the runoff drain through the soil. You may find the smell to be a little strong at first but it fades quickly and the benefits for your plants are definitely worth it.
When to Fertilize Indoor Plants?
It’s somewhat easy to figure out when to fertilize outdoor plants. Most of them come out of dormancy in the spring and prepare to grow flowers or fruits. A good rule of thumb is to fertilize after the first frost to prepare them for the spring and summer ahead.
But house plants are a little different. Because they aren’t exposed to changing sunlight and freezing temperatures, it’s not always easy to know when to fertilize them. Here are some general tips and tricks.
- Even though houseplants aren’t exposed to the elements, most of them are still dormant or semi-dormant in winter and do not need fertilizer. Fertilizing them at this time could result in weak growth and make the plant susceptible to diseases and insects.
- The exception to this rule is any plant that continues to grow through the winter. Any plant that is actively growing should be fertilized but use ½ or ¼ as much in the winter as you would in the summer.
- Plants that continue to bloom in the winter should be fertilized using the regular amount.
- Begin fertilizing dormant or semi-dormant indoor plants at the end of February. Even though they’re indoors, houseplants still sense the changing sunlight and can tell spring is on its way.
- If a plant is not doing well, do not over-fertilize it as this can kill the plant. Make sure it’s getting enough light and water and that the soil isn’t contaminated.
- Don’t add fertilizer to potting soil unless the product says it’s safe to use it that way. Potting soil often has fertilizer in it and adding too much extra can be harmful.
- If you’re purchasing a plant from a home and garden center or greenhouse, find out when it was last fertilized. Taking it home and adding more fertilizer can be harmful to the plant and is easily avoided.
How Often Should You Fertilize Indoor Plants?
Generally, you should follow the directions for the fertilizer you’re using and repeat fertilizer applications as often as they recommend.
How often you should fertilize your indoor plants really depends on the type of fertilizer you’re using.
If you use liquid fertilizer, you have a few options. Some formulas are meant to be applied each time you water. Others should be used every other time or once or twice a month for a bigger feeding.
That said, some liquid fertilizers can be used in multiple ways, depending on how they are mixed. Some products tell you very clearly what ratio of fertilizer to water you should use depending on what type of application you’re using.
Granular fertilizers should be used as often as the package recommends. These usually need to be applied pretty frequently, maybe once every two weeks or so. Because granular fertilizers release into the soil quickly, once the plant uses them up, the soil is ready for more.
Spikes, pods, and other slow-release fertilizers should be applied according to the package directions. They can last as long as two months or more, depending on how many you use and the size of your plant.
How to Fertilize Indoor Plants?
Again, this depends on the type of fertilizer you’re using.
With liquid fertilizers, read the instructions carefully so you know what concentration to use. Usually, you don’t need to use a lot, maybe only a teaspoon or tablespoon. If you can, use a liquid fertilizer that includes a measuring cup or spoon or has one built into the bottle. This helps avoid errors.
Some liquid fertilizers are meant to be applied directly to the roots. If this is the case, avoid the leaves as best you can so the bulk of the fertilizer gets to the roots. Other liquid fertilizers can be applied directly to the leaves. In this case, use a spray bottle and saturate the leaves well.
Granular fertilizers should be measured carefully and mixed into the top one to three inches of the soil. Remember, granular fertilizers release their nutrients pretty quickly after watering so you want to make sure there are granules available for the entire root.
This type of fertilizer can also be mixed into the soil when repotting or transplanting a plant. Again, not all fertilizers should be used this way so make sure you read the directions for the products you’re using.
Finally, slow-release fertilizers should be inserted directly into the soil, about halfway between the stem of the plant and the edge of the pot or as close to the waterline as you can get.
One of the problems with slow-release fertilizers is that they release a concentrated amount of fertilizer around the area of insertion but that doesn’t necessarily mean that the nutrients are getting to all of the roots.
To offset this, make sure you place the spikes evenly around the plant, especially if you have a large plant and are using multiple spikes or pods. This helps even out the distribution of nutrients and can help your plant grow better.
It’s not always easy to find good fertilizer for indoor plants. There are so many different brands to choose from, it can be hard to know which ones really work.
One of the main things to keep in mind is that you have to know your plants. Spend some time researching your plant to learn more about when and how it should be fertilized.
If you’re looking for something that you can apply and forget about for a while, go for a slow-release formula that you only need to apply a few times a year. All you have to do is push them into the soil and you’re covered for weeks to months.
If you like to have a lot of control over how much fertilizer you’re using, try a liquid fertilizer. Since you can apply them every time you water, you get precise control over the amount of fertilizer your plants are getting and when it’s applied.
Finally, if you want something that’s easy to use, go for granular fertilizer. There’s no mixing and no messy liquid, just sprinkle them on, mix them into the top layers of the soil, and water as normal.
UConn Home & Garden Education Center
Through the process of photosynthesis, plants manufacture the sugars and carbohydrates needed for their growth and development. They require at least 16 elements to carry on this process. Plants obtain carbon, oxygen and hydrogen from air and water. Outdoor plants would obtain the other nutrients required for growth from the soil. Houseplants rely on us to supply these nutrients through the application of fertilizers. Under fertilized houseplants often exhibit symptoms of slow growth, weak stems, pale leaves and reduced flowering.
Types of Fertilizers
Houseplant fertilizers come in a number of formulations. Some are wettable powders or concentrated liquids that are diluted with water then applied to the potted plant. Time release fertilizers are available as coated pellets or as spikes. A few are sold premixed and applied directly to the potting soil.
The label on a fertilizer container states the guaranteed analysis or grade. These are the three numbers listed on the package (i.e. 8-7-6). They refer to the percentage of nitrogen, available phosphorus and water soluble potassium contained in the fertilizer. Plants require large amounts of these three nutrients and they are often referred to as primary nutrients or macronutrients. Nitrogen promotes green, leafy growth. Phosphorus encourages flowering and root growth, and potassium is necessary for stem strength and stress tolerance. Secondary nutrients that are required in slightly lesser quantities include calcium, magnesium and sulfur. Ground limestone is sometimes added to potting mixes to supply calcium and magnesium.
The fertilizer label will also state from what sources these nutrients are derived; chemical and/or organic. If synthetic or chemical fertilizers contain trace elements, these too will be listed on the label. Trace elements or micronutrients are needed by plants in very small amounts and include iron, boron, zinc, copper, molybdenum, chlorine and manganese. It is usually safe to assume that organically derived fertilizers, because of their nature, contain some or all of the necessary micronutrients. Potting mixes that have a mineral soil component may also supply sufficient amounts of micronutrients. If you are not using an organic houseplant fertilizer, consider purchasing a chemical fertilizer that does include micronutrients since they are typically not present in soilless potting mixes.
Choosing a Fertilizer
Which is the best houseplant fertilizer for you to use? This will depend on the types of plants being grown, cultural conditions and your schedule. In general, foliage houseplants appreciate fertilizers high in nitrogen while flowering plants respond best to those with higher phosphorus analysis. There are plenty of specialty houseplant fertilizers out there but do examine their labels. Often the difference is more in the packaging than in the amounts or proportions of nutrients supplied.
Purchase a water-soluble powder or liquid concentrate if plants are to be fertilized on a weekly, biweekly or monthly basis. If there will be long intervals between fertilizer applications, select time release formulations in either pelleted or spike forms. These can be applied at intervals from 2 to 9 months and will provide houseplants with a steady supply of nutrients.
Frequently houseplant lovers amass quite a collection of different plant species. Sometimes plants have specific fertility requirements but usually an all-purpose, balanced fertilizer could be applied to all plants. For example, a fertilizer where the three numbers on the package are equivalent or just about equal, such as a 20-20-20 or a 10-8-7.
When to Fertilize
Houseplants respond to fertilizer during periods of active growth. This is usually from March until October. Reduced light and temperatures throughout the winter months often render a plant inactive and it is generally recommended that plants not be fertilized during dormant periods.
The labels on most water-soluble fertilizers recommend monthly applications. Since these nutrients are easily leached from the potting mix, your plants may benefit from more frequent dilute applications. If one teaspoon per quart of water is recommended for monthly feedings, you could feed bimonthly using only one-half a teaspoon per quart or weekly using a quarter teaspoon per quart. This gives the plant a steady, continuous supply of nutrients. This type of regime is often recommended for flowering plants like African violets.
When fertilizing houseplants always follow the directions on the label. More is not better and excess nutrients can harm roots and leaves. Always apply fertilizer to an already moist potting soil to avoid root damage.
Browning roots and leaf tips, wilting, poorly shaped leaves and a white crust on pot rims may indicate overfertilization. Excess nutrients in the potting soil will desiccate or burn tender roots. High concentrations of nutrient salts also prevent the plant from taking up water so wilting is observed.
Often leaching the potted plant with copious amounts of water will reduce excessive fertilizer salt levels. Be sure water can drain freely. Another solution would be to repot the plant, gently removing as much of the old potting mixture as possible, and replacing it with fresh medium.
Keep houseplants healthy and thriving by practicing good watering practices, meeting their light and temperature requirements and providing adequate nutrition through a regular fertilization program.
For pesticide information or other questions please call toll free: 877-486-6271.
Revised by UConn Home and Garden Education Center 2016.
Issued in furtherance of Cooperative Extension work, Acts of May 8 and June 30, 1914, in cooperation with the U.S. Department of Agriculture, the Dean of the College, Cooperative Extension System, University of Connecticut, Storrs. The Connecticut Cooperative Extension System is an equal opportunity employer and program provider. To file a complaint of discrimination, write USDA, Director, Office of Civil Rights, Room 326-W, Whitten Building, Stop Code 9410, 1400 Independence Avenue, SW, Washington, DC 20250-9410 or call (202) 720-5964.
How to Care for House Plants
Never try to equate fertilizing with feeding. Plants get their energy from light, not fertilizers. Unless good light levels are supplied and the plant is growing well, fertilizing will do more harm than good. Newly purchased or repotted house plants should be given a few months rest from feeding so that they can use up the nutrients already present in their growing mix.
Fertilizing is very important for plants growing in soilless potting mixes.
Plants require three major elements for healthy growth: nitrogen (N), phosphorus (P), and potassium (K). These are always listed on fertilizer labels in the form of ratios: 6-12-4, for example, indicates 6 percent nitrogen, 12 percent phosphorus, and 4 percent potassium. Most fertilizers also contain some of the minor elements — magnesium, boron, iron, etc. — that plants also need for growth.
Generally speaking, fertilizers rich in nitrogen (the first number) will stimulate healthy, green growth of foliage, while those rich in phosphorus (the second number) will encourage good root development and improved flowering. Those rich in potassium (the third number) will help build up reserves for plants that have a dormant period.
A fertilizer labeled 30-20-20 would be good for leaf development and would be most recommended for foliage house plants, while flowering house plants would prefer one richer in phosphorus, such as 15-30-15. Most foliage house plants get along fine with an all-purpose or high-nitrogen fertilizer, while one with a high proportion of phosphorus is best for flowering house plants.
Most plants these days are grown in soilless potting mixes that offer very little in the way of nutrients, making regular fertilizing very important. One way to make sure your house plants get the fertilizer they need is to use a constant feed method.
Simply take a liquid or water-soluble fertilizer designed for a monthly application and reduce its dosage by four. For example, if the label states it should be applied once a month at a rate of one teaspoon per gallon, apply it at every watering at a rate of ¼ teaspoon per gallon. Once a month, take the plant to the sink and leach it carefully by running clear water through its pot until the excess fertilizer runs into the drain. This helps prevent buildup.
Choosing Fertilizers for Your House Plants
Ready-to-use liquid fertilizers are convenient, but expensive, since you pay for the water they contain. Water-soluble fertilizers, available in powder or crystal forms, are just as efficient, but are more economical because you add the water yourself.
Some people prefer the practicality of slow-release fertilizers. These are available in granule form to be mixed with the soil or in spikes and tablets that are pushed into the potting mix. They need only be applied once every few months. The label on the fertilizer will suggest a recommended frequency.
Organic versus Chemical
Both organic and chemical fertilizers are available in a wide variety of concentrations. Since chemical fertilizers applied to house plants do not leach out into the outside environment, even growers who use only organic fertilizers outdoors often have no qualms about using chemical ones on their indoor plants.
One popular organic fertilizer is liquid seaweed. It is applied as a foliar spray and absorbed by the plant’s leaves.
House plants do not require a shed full of expensive gardening equipment. In fact, most indoor gardeners find they can get along fine with simple kitchen utensils: a spoon for repotting, a pair of scissors for cutting off yellowing leaves, a sharp knife for taking cuttings, and a recycled window spray bottle for applying pesticides. The most important tool for proper plant care is a good watering can. Look for one with a long but narrow spout.
In the next section, we’ll talk about potting house plants.
Want to learn about house plants by type? Try these:
- House Plants
- Full Sun House Plants
- Bright Light House Plants
- Filtered Light House Plants
- Light Shade House Plants
- Hanging Basket House Plants
- Floor Plant House Plants
- Table Plant House Plants
- Terrarium Plant House Plants
- Very Easy House Plants
- Easy House Plants
- Demanding House Plants
- Temporary House Plants
- Flowering House Plants
- Climbing or Trailing House Plants
- House Plants with Colorful Foliage
- Fragrant House Plants
When I first started growing my own fruit and veg in containers, I found information about how, when and what to feed plants in containers surprisingly hard to come by. Perhaps this isn’t surprising. Crop nutrition is never going to be a sexy subject. At its best it’s a complicated and slightly smelly one. Still, if you want your plants to thrive in containers, you need to put a bit of thought into feeding them. You can dedicate a lifetime to learning about crop nutrition. But I’ve found a little knowledge can go a long way.
Plants need a mix of nutrients, just as humans need to consume a mix of protein, fat, carbohydrate, minerals and vitamins. They particularly need nitrogen (N) for leaf growth, phosphorus (P) for root growth, and potassium (K) for fruit growth. All plants need all three, but leafy crops particularly need nitrogen, and fruit crops won’t develop well without enough potassium. They also need a wide range of other nutrients, often in tiny quantities. I think of these as the equivalent of the vitamins and minerals we need to keep us healthy. Finally, plants need bacteria and fungi in the soil to break it down and release food to their roots, just as humans need bacteria to digest food in our guts.
Most compost or growing mixes you can buy in garden centres only contain enough nutrients for six weeks’ growth. So for optimum results, you need the right fertiliser (rich in either nitrogen or potassium) and you need to make sure the plant has enough vitamins and minerals and that there is plenty of soil life in your pots.
Here are some of the easiest ways to add these critical ingredients.
Your salads and other leafy crops won’t flourish unless they have enough nitrogen.
Chicken manure pellets are cheap, easy to source, and contain most of the essential nutrients for plants. They are particularly high in nitrogen. I use them all the time for rejuvenating old compost to grow salads. Simply mix a handful into your compost before you plant your salads.
If you have a supply of nettles nearby, you can make nettle tea by soaking nettles in a bucket of water for two weeks. The resulting brew is high in nitrogen and other goodies (if a bit whiffy!).
Take care not to add too much nitrogen to fruiting crops – you may get lots of leaves and not many fruits. Try experimenting – a little bit at a time is the safest strategy.
To get good yields of tomatoes, runner beans, squash, chillies, strawberries and other fruiting crops from containers, you need to regularly add additional potassium (K).
The easiest way to do this is to buy a bottle of tomato feed. Although called tomato feed, this will do the job for all fruiting crops.
You can also make an excellent potassium feed by soaking comfrey leaves in water for a week to make comfrey tea, which is a more organic solution. You can find comfrey alongside canals and in town marshes where it can grow wild in abundance – or you can buy liquid comfrey online. This is wonderful stuff, though it is even smellier than nettle tea.
Vitamins and minerals
Liquid seaweed is an excellent source of vitamins and minerals. You can add it to your watering can once a week to keep your plants healthy. Or, to make a precious bottle go further, you can spray it on to the leaves of your crops using a simple hand spray (an empty spray bottle, cleaned well, works perfectly).
Rock dust (available in some garden shops) is another source of minerals – mix a few handfuls into the soil in each container.
Healthy soil contains an invisible and amazing array of bacteria and fungi which digest the nutrients you are adding, releasing it to the roots of your hungry plants.
You can buy various products such as mycorrhizal fungi to add life to your pots. But one of the best sources is worm compost or worm tea. You can make this at home in a wormery.
Worm compost is fantastic for containers: as well as soil life it’s rich in the vitamins and minerals your plants need, as well as some of the major nutrients. Mix 10 – 25% into old compost to rejuvenate it, or add 5 – 10% to new compost to add soil life. Add a layer of an inch or two to hungry crops like courgettes and tomatoes to give them a boost half way through the growing season.
How much to feed?
Feeding crops is as an art as well as a science. How much you feed depends on lots of variables: the size of pot, what compost you’re using, how big your plant is, and how fast it’s growing. The secret is to give it a go, observe the difference, and learn from the results. As a general rule, little and often is the safest strategy (too much feeding is as bad as too little). And feed more when your crops are fruiting.
I’m only scratching the surface of a big subject here – but following these simple rules can, in my experience, transform small harvests into more significant ones.
Interested in finding out more about how you can live better? Take a look at this month’s Live Better challenge here.
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Feeding Your Houseplants
If you don’t feed your houseplants regularly, they tend to underachieve. You should start feeding regularly once they fill their pot with roots. If you want them to remain healthy and create a lush, attractive display, you need to give them regular feedings.
From early spring into summer, both leafy plants and flowering plants require some feeding at 10-14 day intervals. Houseplants that flower only in the winter should be fed the same way, but only when they are flowering.
Liquid Fertilizer for Feeding Houseplants
Most people feed their houseplants by mixing concentrated liquid fertilizer in clean room temperature water and watering the plants with the solution. Make sure you don’t make the mixture too strong and mix the solution according to manufacturer recommendations. Be sure the compost is already moist, which will help the fertilizer absorb easier and quicker. Mix only enough fertilizer to feed your plants. Don’t make up large quantities and store the mixture because it can get stronger while it sits.
Feeding Sticks and Pills for Feeding Houseplants
Feeding sticks are another quick and easy way people fertilize their indoor plants. All you do is push the fertilizer pegs into the compost about 1 cm from the pot’s side. There are fertilizer pills as well. Both the sticks and the pills give the plants food over a longer period of time, but they sometimes encourage the roots to become congested around them.
When Not to Feed Plants
Plants that flower throughout the summer shouldn’t be fertilized with pills and pegs past the midsummer growing season. The last fertilizer peg or pill that you would administer will keep the plant fertilized throughout its flowering process. If you have winter flowering plants, insert the last peg or pill in autumn and early winter.
Feeding your plants are not hard things to do. Sometimes, it can be time consuming and they are definitely chores that fall low on the list at times. But you will reap many rewards in the long run with the beauty you are creating.
- Liquid fertilizer: Liquid fertilizers are added to your watering can. Depending on label instructions, you might fertilize every time you water or every other time. The type of plant will also impact this, as some—especially those with dramatic large blooms—may require more frequent feeding. Always study up on the plants to learn about the specific nutritional needs. Liquid fertilizer provides a steady supply of nutrients that you can precisely control. It’s easy to suspend feeding when the plant is dormant during the winter months, for example, or step up the feeding when they are sending up new growth. The disadvantage, however, is that you need to remember to do it every time.
- Slow-release fertilizers: These products have quickly become favorites for many gardeners and professional growers, both for indoor and outdoor plants. Slow-release fertilizers are coated in time-release shells that slowly leach nutrients into the soil. The individual pellets have coatings of different thicknesses that dissolve at different rates, so the actual release of the fertilizer is staggered over time. A single application can last between four and ninth months. The main drawback is the higher cost of slow-release fertilizer, but because it last so long, it evens out in the end.
- Granular fertilizer: These are dry pellets of pure fertilizer that can be mixed into the potting soil by hand. Although more commonly used in outdoor gardens, they can also be used for containers—although it can be tricky. Granular fertilizer dumps all of its nutrients at once when the pot is watered, making it hard to control how much the plants are receiving at once. This type of fertilizer is quite inexpensive, but not a great choice for feeding houseplants.
Although most of the fertilizers have been packaged for large commercial operations — hence the fancy formulas — probably the most popular for the average house plant grower is the 20-20-20 formula. This one will supply general nutrition and fill most of the plants’ needs.
These water-soluble fertilizers also contain the micronutrients that plant professionals are now recognizing as essential to proper plant growth. Although these nutrients are present in some soils, they are not in all. Even though the micronutrients are used by plants in minor quantities compared to the big three nutrients, they are important. They include manganese, boron, zinc, molybdenum, copper and cobalt. And the best way to know the individual plant’s needs is to grow it and note how well the plant responds.
Some fertilizers are sold only in liquid form, particularly the fish emulsions, which have a low-nutrient formula. These mild fertilizers are often recommended for ferns, because they are of low concentration and will not burn roots. Be sure to use these fertilizers carefully, however, since they have objectionable odors unless mixed properly and the drain saucers are emptied promptly.
One type of fertilizer is sold as a liquid concentrate and is bottled with a dropper. The concentrate is doled out into a watering can at the label’s recommendation to supply a particular dilution for house plants.
Since there are so many plant-nutrition products available, it is important to read product labels carefully and follow the application rates.
A practical note: Most plants go through a dormant or rest period at some time in their yearly cycle. This rest period usually comes during the winter months, when there is less light to encourage flower bud development, and there are many cloudy, sunless days.
But the days are gradually becoming longer, and green growth indoors is being stirred out of its winter lethargy. Allow the plants to grow first before even thinking about using any fertilizers. And then apply them only to spur flower bud formation. Many of the popular indoor house plants burst into bloom with the springtime, and a half-rate application may just be the thing to stir them.