Fertilizer for Tomatoes, Peppers, and Eggplants

Peppers on vertical wire

cherry tomatoes in potsSummer fruiting crops such as tomatoes, peppers, and eggplants will benefit from a side-dressing of organic fertilizer when they first set fruit and every 4 to 6 weeks thereafter. An alternative is to water in a dilute solution of fish emulsion, seaweed extract, or kelp meal every 10 days.

Feed fruiting crops that have flowered and set fruit with liquid balanced fertilizers such as compost tea, comfrey tea, or solid organic fertilizers in powder, pellet, or granular form. An ideal fertilizer ratio for fruiting tomatoes, peppers, and eggplants is 5-10-10 with trace amounts of magnesium and calcium added.

Liquid organic fertilizers can be watered-in around the base of plants or applied directly to crop leaves as foliar feeds. Solid fertilizers can be applied as a top dressing or band of fertilizer around the base of each plant; solid fertilizers should be scratched into the soil with a garden fork or trowel.

Best tips on How to Grow Tomatoes.

Amount of Fertilizer

If a manure fertilizer was added to the soil just before planting, reduce the fertilizer rate by one-half. Manures are generally high in nitrogen. A balanced fertilizer contains equal or near equal parts nitrogen, phosphorus, and potassium.

When using a commercial organic or non-organic fertilizer, always follow the label directions on the package. Too much fertilizer will be more harmful to plants than not enough. When in doubt, cut the recommended application of fertilizer in half, check the reaction of the plants in 10 days, and then apply the second half of the fertilizer if plants are doing okay.

For higher yields of fruiting crops such as tomatoes and peppers, extra phosphorus and potassium should be given after flowering and fruiting. To increase the flowering of tomatoes, peppers, and eggplants, give the plants an Epsom salt solution–1 tablespoon mixed with a gallon of water.

For higher yields of leafy crops and crops that have overwintered in the soil such as autumn-planted onions, a top dressing of nitrogen-rich fertilizer will act as a crop booster.

Fertilizer Timing

It usually takes 10 to 12 weeks from the time transplants are set in the garden for tomatoes, peppers, and eggplants to ripen their first fruit. Fertilize these crops with a side-dressing, one month, and then again two months after transplanting—as a guide.

Foliar Feeding

Vegetables can take a limited amount of nutrients in through their leaves; this is called foliar feeding. Use a watering can with a fine rose and foliar feed with compost tea, comfrey tea, or seaweed extracts.

Foliar feeding is particularly helpful as a boost or tonic for plants that are lagging or off to a slow start. Foliar feeding commonly results in plants gaining a deep green, healthy look soon after feeding.

Dry fertilizers are generally watered in after they are applied as a side-dressing. Foliar feeding does not require watering of the soil before or after applying fertilizer. Foliar feed when the soil is already moist or when the weather is particularly dry and plants can use both a watering and fertilizer application.

Click on these other article titles for more information:

Fertilizer Side-dressing Vegetable Crops

Organic Fertilizers and Soil Amendments

Vegetable Plant Nutrients: Sources and Deficiencies

How to Make Compost Tea

How to Make Comfrey Tea


Written by Stephen Albert

Stephen Albert is a horticulturist, master gardener, and certified nurseryman who has taught at the University of California for more than 25 years. He holds graduate degrees from the University of California and the University of Iowa. His books include Vegetable Garden Grower’s Guide, Vegetable Garden Almanac & Planner, Tomato Grower’s Answer Book, and Kitchen Garden Grower’s Guide. His Vegetable Garden Grower’s Masterclass is available online. has more than 10 million visitors each year.


Comments are closed.
  1. My tomato plants tends to die off as they grow, even some branches with fruits wither and die. Some braches start to dry off at the back and leaves would dry off but the new leaves keep developing but eventually the whole branch will die. It happens to pretty much all my plants. They look somehting similar to this
    Any suggestions? Thanks

    • The plants are likely suffering from a soil-borne disease that is carried up into the plant in soil water.
      The best course is to not plant any tomato family plants in this planting bed for three years.
      You should remove the plants and place them in the trash; you can place clear plastic over the planting bed and solarize the soil; this may speed the recovery.
      How to Identify Early Blight

  2. What type of fertilizer is best for eggplants? How often should these plants require fertilizer? We have a lot of flowers and the fruits are looking fine. But I have noticed that the leaves tend to turn yellow right after fertilizing.

    • You may be using a fertilizer that is too high in nitrogen. Use 5-10-10 and follow the label directions or feed with a dilute solution of fish emulsion every 10 days.

  3. I planted my tomato seed directly in the soil but I noticed that it’s not growing well. Please what can I do not to lose the tomatoes. HELP PLEASE!

  4. My Japanese Eggplant is producing fruit, not growing very much and the leaves have turned leathery and gold grey color. I have given them epsom salt and tomato time release fertilizer. no sign of pests no spots or holes. The fruit though small is fine and i am still getting flowers though the plant is stunted. WHAT IS WRONG????

    • There are a few reasons your eggplants are slow-growing: (1) Eggplants are very temperature sensitive. Night or day air temperatures less than 75F will slow growth; the same is true soil temperature less than 70F. Planting when temperatures are not optimal can stunt eggplant growth; the plant may never fully recover. Don’t set eggplants in the garden until temperatures are warm. Once in the garden, protect eggplants from the chill; place a plastic tunnel or row covers over the plants when temperature dip below 70F; place black plastic around the base of plants to warm the soil. Conversely, temperature greater than 90F can slow or stunt growth; protect plants from midday hot temperatures with shade cloth. (2) Soil moisture is insufficient for cell development. Keep the soil evenly moist; do not let it dry out. Roots must be able to draw up moisture without interruption.

    • The best fertilizer for tomatoes is aged compost worked thoroughly into the soil. Do this during winter or at least a few weeks before planting. Generally if you spread 2 inches of aged compost across the planting bed twice a year the soil will be renewed and nutrient rich. If you do not have aged compost use a commercial organic planting mix. If you are buying boxed or liquid fertilizer, choose an organic fertilizer with the ratio of about 5-10-10. Follow the directions on the label.

  5. Hi !…Very nice website. I grow tomatoes in big plastic containers 12 inches dia and peppers in rectangular beds of 4 feet by 9 inches. I had lots of peppers both cayenne and Bell type.

    I grew one Beefsteak tomato plant but it did give only one tomato all over the year. Foliage was good but one side thick branch was becoming brown and then dried, seems to be Anthracnoes. I bought new pots and new soil and put some Heirloom varieties and in one old container I left old and new soil mixed up and Bonie’s Beef master variety from Wal-mart. Will it do or they will get diseases again. I threw away old tomato plant branches away. Can I also put solution of Bayers Adanced formula for 3 in one treatment of diseases? I put this solution in only one pot which was diseased. Thanks in advance for early responce.

    • Once you have had a disease, it’s best to start with all new soil. Diseases can live on in the soil. Try an All-America Selection tomato such as Celebrity if you continue to have problems with heirlooms. AAS selections grow well around the country in all types of gardens.

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