Tomato Fertilizer: How To Feed Your Plants For Ultimate Harvests

A good tomato fertilizer will make or break your tomato harvest. Find out about tomato fertilizers and how to use them with our handy guide!

Great harvest of tomatoes


If you want a bumper crop of tomatoes, you’re going to need a good tomato fertilizer. But the best forms of fertilizer may not be readily apparent. Tomatoes are heavy feeders, and they’ll want all kinds of stuff to promote both tomato plant and fruit growth.

So to clear up all this confusion, I’m going to offer you solutions for your tomato fertilizer dilemma. We’ll go over how best to prepare the soil prior to planting. I’ll explain how to minimize your chances of blossom end rot and other related problems. And hopefully, by the time you’re done reading, you’ll have every piece of information necessary to grow an abundance of “love apples”.

Rich Soil In Advance: Preparing Your Beds

Fertilizing the soil with tomato fertilizer before planting
Loosen and prepare your soil before planting. Source: Ethan Hurd

It’s essential before you even plant your tomatoes to make sure that the beds are full of nutrition. After all, the young plants are heavy feeders too, and will devour whatever you put down for them!

I like to amend my beds prior to planting tomatoes with a mix of homemade compost from my compost tumbler, some well-composted animal manure (horse manure or chicken manure is great, but cow manure is also fine), and a few other components.

Vermicompost from my worm composter is a great additive. Not only does it offer plenty of nutrients to the soil, but it provides a host of microorganisms. These microscopic soil dwellers will help the tomato plant absorb food better and repel against some forms of soil-dwelling pests.

After using eggs in the kitchen, I wash and dry the shells and make a powder of them. I will blend that powder through my beds as well. The eggshells provide a much-needed calcium boost for next year’s tomato plants. As long as there is adequate moisture, the broken down calcium carbonate helps with future nutrient issues like blossom end rot.

Ensure that your tomato plants are in beds with well-draining, loose soil. If they’re too compacted, the tomatoes will have problems getting their root system developed properly.

A good rule of thumb is that you should be easily able to push your fingers into the soil without too much force exerted. If you can’t, it’s too compacted.

When To Fertilize Tomatoes

Newly forming tomato
Fertilize with phosphorus to encourage flowering and fruiting. Source: Southern Gardener

Generally, you will fertilize tomatoes once when you plant, and then wait for a while as the plants settle in.

Add fertilizer to the planting hole, working it lightly through the soil. If it’s an organic fertilizer, you’re set. If it’s chemical, place a thin layer of normal soil between the fertilizer and the base of the young plant. This prevents root burn while the plant is unwinding itself from being in a pot.

Once your plants start to set fruit, you can begin to fertilize tomatoes again. At that point, it’s easiest to use a diluted liquid fertilizer or “fertilizer tea” and fertilize around your tomato plants every couple of weeks until the end of the harvest period. Try to avoid getting the fertilizer on the leaves — aim it in a ring about 6″ out from the base of your plant.

You can also use dry tomato fertilizers around your tomato plants. Simply work them into the top layer of soil lightly, then water them in. If you need to water anyway, this may be the easiest option for you.

Before you fertilize, be sure your tomato plants have been thoroughly watered. That ensures that they aren’t trying to suck up pure fertilizer instead of the water they also need. Once they’ve been watered, then add your fertilizer and you’re set for another couple weeks.

Organic Fertilizers Vs. Chemical Fertilizers: Which Is Better?

Tomato fertilizer
Keep fertilizer on hand so you can fertilize as needed. Source: Chiot’s Run

There’s been a lot of debate as to which is better for your tomato plants. The plants themselves do not seem to care much whether their nitrogen, potassium, and phosphorous come from chemical or natural means. However, you might!

Many people are concerned about whether chemical tomato fertilizers will come through in your harvested fruit. There are few studies that show any significant signs of chemical additives appearing in your harvest. If the potential risk outweighs the benefit, you may want to use organic fertilizers.

I personally prefer organic methods in my garden. This is largely because the wide variety of chemical options out there are formulated to only provide the N-P-K fertilizers and lack a lot of the micronutrients that my plants may need. Further, there can actually be too much nitrogen, potassium, or phosphorous in the soil, and that can leach off into local water via runoffs and the watershed. It’s more environmentally friendly to build your soil naturally!

Organic fertilizer tends to be slow-release and is formulated from products like alfalfa meal, blood or bone meal, and the like. The favorite organic tomato fertilizers among the EG team are Espoma Tomato Tone and Espoma Liquid Tomato Food. and These gradually break down in the soil and offer a continuous source of nutrition for my plants. They also help build the soil, providing good organic material.

As any long-term gardener can tell you, the better your soil is, the better your plants will grow. Building the soil rather than simply adding a chemical will turn out to be the best choice in the long run.

However, let’s not rule out chemical means altogether. If you want to use a product like Miracle-Gro Tomato Plant Food, you can. It’s better that your tomato plants get the nutrition that they need, no matter what! But I do encourage going organic whenever possible. It’s better for the environment and for your garden soil, and you’ll have better harvests over time.

I still do encourage adding a little extra calcium to your soil if you opt for a chemical alternative. The last thing you want is to have huge, happy plants that don’t produce fruit!

Great Organic Tomato Fertilizer Options

You can opt to purchase an organic tomato fertilizer, or you can make your own.

At a 3-4-6 level, there is Espoma Tomato-Tone, which incorporates calcium into its blend to prevent blossom end rot. Espoma tomato fertilizer also has some beneficial soil microbes added to help your plants. It’s constructed of a blend of feather meal, poultry manure, bone meal, alfalfa meal, humates, sulfate of potash, and gypsum.

The Espoma tomato fertilizer has lots of potassium that may not be as necessary if you have potassium-rich soil already. But if you do a soil test and discover your potassium levels are low, it can help! We believe strongly enough in Espoma’s products that we carry Espoma Tomato-Tone in our shop.

I also occasionally use Doctor Earth Organic Tomato, Vegetable & Herb fertilizer. Made of a blend of fish bone meal, feather meal, potassium sulfate, humic acid, and seaweed extract, it provides a slow-release fertilizer with a 5-7-3 NPK. Slightly higher in phosphorous to promote flowering (and subsequent fruiting), it also is a good source of nitrogen.

Doctor Earth tomato fertilizer also incorporates beneficial soil microbes and mycorrhizae to help protect the plant and help it take up its nutrients more readily. It can be used just as it is as an additive to the soil, or brewed into a tea and then added in liquid fertilizer form around your tomato plants.

Homemade Tomato Fertilizer

Results of nitrogen and phosphorus rich fertilizer
Tomato plants fertilized with both nitrogen and phosphorus-rich fertilizer. Source: Lorin Nielsen

There’s been a few different variations that I’ve used over the years to fertilize tomato plants, but it usually depends on what’s available to you.

If you have chickens, chicken manure is phenomenal for tomatoes, but be sure to compost it down first. Pet rabbits and hamsters are also great suppliers of rich manure for tomato-growing, especially as they tend to have a lot of alfalfa in their diets.

The Base

A good tomato fertilizer blend utilizes a base of high-quality compost. I use a compost that I’ve made myself from my yard waste and food scraps. If you don’t have homemade compost, you can do a blend of composted animal manure and either peat moss or coconut coir thoroughly blended together. This creates a “fake” compost which should work just fine as a starter.

Take about a half-gallon of your compost and place it into a large mixing tray or bucket. Make sure any large clumps are broken up and that it’s well-combined. At this point, you need to consider what, exactly, your tomatoes need.

I like to add a couple of cups of vermicompost to my compost blend to help kick up the beneficial microbes in the soil and provide a good-quality fertilizer additive. I also add the other amendments we discussed previously. If you have rabbits or hamsters, add a couple of cups of their droppings to this mix as well.

Now Add Nutrients

Once you have those well combined, add a cup of wood ashes to kick up the potassium and phosphorous level a bit.

If you don’t have a woodburning fireplace, you can add a couple of cups of kelp meal to raise the potassium. A half cup to a cup of bone meal will raise the phosphorous.

You can also add used tea leaves or coffee grounds for a low nitrogen boost (I do 1-2 cups). 2 cups of alfalfa pellets or leaves will give a slow-release nitrogen boost as well. If using pellets, lightly dampen them so they fall apart before adding them, so they will combine evenly through your mix.

If you want to give them a much higher level of nitrogen, consider adding a half cup of blood meal to your mixture. Blood meal varies between 9-14% nitrogen content, and a little bit goes a long way. But don’t add too much fertilizer in blood meal form.

You can also throw any pet hair or human hair in there that you have on hand. Be sure to cut up the hair finely so it will mix into the fertilizer, rather than clumping. Hair will break down in the soil as a slow-release nitrogen source, and will also provide keratin, a protein that your tomatoes will appreciate.

Ideally, make your fertilizer about a month in advance, blending it thoroughly together and storing it in a sealed bucket. This gives your fertilizer time to cure before use.

What Tomato Fertilizer Ratio Should I Use?

Tomato blossom end rot
Avoid tomato blossom end rot by ensuring there’s calcium in your soil. Source: Scot Nelson

As mentioned before, nitrogen spurs plant growth. So, early on, your plant will require more nitrogen, especially if starting from seed, feeding tomato seedlings, or planting a new transplant.

Once your tomato seedlings have grown to a good size, you can cut back on the nitrogen and provide more phosphorous to stimulate fruiting and more potassium for good root structure and fruit setting.

This means that your tomato fertilizer will change as the tomato plants mature, and that’s okay! The best tomato fertilizer is the one that provides what your plants need at that particular moment.

For me personally, I opt for something like a 10-5-5 or a 10-5-8 when I’m first planting. This gives my new starts a great kickstart, and the latter encourages great root development. However, once they are a good size, I switch over to a 5-10-5 or a 5-10-10. If I’m fertilizing tomatoes every couple of weeks, I can opt for a lower-strength fertilizer and just remain consistent in my feedings. Too much fertilizer can be just as detrimental as not enough.

Making Liquid Fertilizer

If you’d prefer to use your fertilizer as a liquid, you need to make fertilizer tea to feed tomato plants. This process takes a little time, but it’s well worth the effort.

Mix one pound of your tomato fertilizer for each gallon to gallon and a half of water in a large container. I use a five-gallon bucket for this purpose. Stir the water and fertilizer together well, and be sure to stir it a couple of times a day. Allow this to steep for five days in an area where it’s protected from both cold and heat.

After five days, strain off the liquid and use it immediately, undiluted. But don’t throw out the remaining solids! Those can either be sprinkled around your plants or added to your compost pile, because they still have some nutrition yet to give.

Most organic fertilizer that is commercially-available can also be used as a fertilizer tea. They often have recommended recipes for the best fertilizer tea for their specific formulation. You can follow yours or simply go with my version, either will work. The real goal is to give your liquid three to five days of steeping time to allow the nutrients to be absorbed by the water.

What Is The Best Fertilizer For Tomatoes?

Great harvest of tomatoes
Fertilizing tomatoes regularly can produce huge harvests – bill for size comparison!. Source: Lorin Nielsen

I personally feel that there is no single “best fertilizer” for tomatoes, because it is all varying depending on what your soil will need. But there are a few reasonably good choices I will recommend.

Earlier in this piece, I mentioned Doctor Earth Organic Tomato, Vegetable & Herb fertilizer. For most people, this is going to be a great choice. However, it’s important to pull out your soil test kit first and see what you need.

Espoma Tomato-Tone is another reasonable choice for fertilizing tomatoes, especially if your soil needs a bit more potassium than phosphorous or nitrogen.

However, you can opt to use your own homemade blend, and it can work with great effect. Be sure to have your soil tested first to determine what your soil needs. Also, be sure that both nitrogen and phosphorous are well-represented so that you are encouraging tomato plant growth and healthy blooming.

Ensure that you have calcium in your soil to prevent blossom end rot. It doesn’t matter if it comes from a commercially-available fertilizer or if it comes from powdered egg shells, just be sure it’s there!

And finally, the best fertilizer for tomatoes is the one which you use. If you don’t fertilize them, your tomatoes will not be as abundant or as healthy as plants you do fertilize. So, no matter what, use something during the growth period to give your tomatoes the food they so desperately desire.

Ready for that bumper crop of tomatoes yet? If you fertilize properly, you’ll be canning your produce all season long!

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