Best Fertilizers for Tomatoes

Tomatoes are arguably the most popular plant grown in the home vegetable garden, and tomato fertilizers are a hot topic. Tomatoes are very hardy plants and can be grown in almost every hardiness zone.

One of the most frequent questions many tomato gardeners ask is, “What is the best fertilizer for tomatoes?”. Tomatoes may need fertilization at certain times of their growth depending on what available nutrients are in the soil. You can find more on when to fertilize tomatoes here – when to fertilize tomato plants.

Here are the best fertilizers for tomatoes.

Find Out What’s In Your Soil First

Heirloom TomatoesBefore fertilizing your tomatoes, you need to find out what nutrients are already available in your soil.

If your soil has high levels of nitrogen, there may be no need to add more nitrogen.

It’s unlikely your soil has high levels of nitrogen, because the nutrient easily leaches from soil, but it’s just an example.

The best way to determine your nutrients levels in the garden soil is by performing a soil test. Home soil test kits can tell you some primary information, such as macro-nutrient levels and pH.

For a complete soil analysis it is best to have the test completed by your local cooperative extension. They will be able to analysis your soil for all macro and micro nutrients in your soil, plus lead and mercury levels. A soil analysis is generally inexpensive, ranging from $7 to $15 depending upon location.

Different Nutrients for Different Stages of Growth

Tomatoes need different nutrients at different stages of their growth cycle. Generally, when planting it is a good idea to add more phosphorus, because phosphorus helps to develop strong roots. Developing the root system is very important during the early growth of the tomato plant.

Once the tomato plant is established the levels of potassium can be slightly raised for vigorous plant growth and to help establish fruits. A good source of potassium is wood ashes from a fireplace that is worked into the soil.

High levels of nitrogen should be avoided. Although tomatoes do need some nitrogen for foliage growth, too much nitrogen can create big, bushy tomato plants but less fruit. Here are the best fertilizers for tomatoes and when to use them.


High quality compost is created from decomposed organic matter and can be added around tomato plants throughout the year.

As a matter of fact, it is recommended that compost be used as a fertilizer for tomatoes during the entire growing season. Before planting tomatoes, mix compost in the soil at a depth of about three to six inches. Work the compost in the soil well using a garden fork or hoe.

Once the tomato plants have become established, fertilize them with compost as a side-dressing around plants about once a month.

Enriching your garden soil well with compost will give your tomatoes all the nutrients they need throughout the season. Compost will also improve soil structure, which in turn will improve soil drainage and provide beneficial microbes.

Tomato-Tone Organic Fertilizer

Tomato_tone Tomato FertilizerTomato-Tone Organic Fertilizer is a natural, granule fertilizer for tomato plants derived from plant materials and other organic matter.

It features a N-P-K rating of 3-4-6, that’s 3% nitrogen, 4% phosphorus, and 6% potassium. Tomato-Tone also contains beneficial microbes which encourage root development and strength.

Tomato-Tone can be used when transplanting tomatoes in the garden and once the tomato plant has become established. Just use a handful of Tomato-tone per plant.

For more information on how I use Tomato-Tone fertilizer on my tomato plants, see Fertilizing Tomatoes.

Tomatoes Alive!

Tomatoes Alive! is another granule fertilizer for tomato plants that aids photosynthesis, encourages root development and provides beneficial soil microorganisms. It is a slow release fertilizer that gives tomato plants the nutrients it needs as it develops, eliminating the chances of stress and burning.

Tomatoes Alive! only needs to be used on tomatoes twice a year for fantastic tomatoes.

GSC Organic Tomato Fertilizer

GSC Organic Tomato Fertilizer

Gardener's Supply Company's Organic Tomato Fertilizer is a slow-release granular fertilizer for tomatoes that boasts a 5-6-5 guaranteed analysis and gives tomatoes all the essential minerals they need. It also includes plenty of phosphorus for big, abundant fruit.

Mix GSC Organic Tomato Fertilizer in the soil when transplanting and use as a side-dressing several times throughout the season. It’s all natural formula will not burn plants, and it conditions the soil for great root growth.

Compost Tea

Although compost tea is not actually a fertilizer, but it is an important part of growing amazing tomatoes. Compost tea acts as a soil conditioner, softening the soil making it easier for tomato plants to absorb nutrients.

Compost tea has been known to help prevent disease and some pests in plants. It can be applied directly to the plant and to the soil around the plant once a week for optimum results.

Grow Fantastic Tomatoes

12 Comments on Best Fertilizers for Tomatoes

  1. Is it alright to use compost manure to help the soil? I bought some at a local home improvement store but am not sure if it is ok to use.

    • Hi Jenny – It is most definitely OK to use composted manures in ther vegetable garden. Just make sure they have been composted for at least 6 to 9 months and it’s manure from an herbivore (cow, horse, goat, rabbit, chicken, alpaca, etc).

  2. Something I found works great is to get horse manure and half fill a 50 gallon container with it. Then fill with water, let about a week and water with this tea. The better fed the horse, the better the tea.

    • Dalton,I use horse manure tea and have been for sometime and me or my family have never been sick.My grandfather and grandmother are in their 90’s and I learned this from them so can’t be all bad.

  3. joey baulbaggio // May 9, 2011 at 2:12 am // Reply

    Hey Dalton are you out of your mind? Basically you are talking about making shiddt tea??? This could make people sick or even kill them. Please do not give out such idiotic advice,. There are many safe ways to feed plants.

    • Hey Joey, I have been making cow manure tea for over 35 years. As well as many of my friends and the older gardeners that tought me of this. Works great and not once did anyone get sick. I suppose you think burying dead fish in your garden is better, or letting your food scraps to rot is good too?

  4. hi tee
    I am a new gardener and my tomtoes are turing yellow at the top of the garden is only 20-7 very small This is the frist year for the gardern. can you help me get what i need to clear up t
    he problem. thanks pat

    • Hi Pat – It can be sometimes unusual for the leaves to start yellowing at the top. Yellowing leaves can be caused by under watering, over watering, or lack of nitrogen.

      If you don’t think it’s an issue with watering then I would suggest sprinkling some Tomato-tone, or other organic fertilizer, around the plants and water it in well. You can also use compost tea, fish emulsion, or worm tea.

  5. I have been using horse manure and tea on my garden for years, it has always worked well for me!

  6. Hi.
    Is red loamysoil good to
    Grow tomatoes


  7. can you crush cuttlebone bone into soil or will it hurt never grew a tomato plant before. I am using fish fertilizer too. as I said my first year to plant anything

  8. My garden center recommended Vegetable fertilizer with a ratio 20-20-20 is that fine or is it to high?

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