Tomato Fertilizer – The ONLY Guide You Need

You want to grow big, healthy tomatoes but don’t know how to get started. The tomatoes are erratic, and most gardeners struggle to get them to grow big and healthy. One minute they’re doing great and the next, they’re wilting and producing no fruit.

Using fertilizer is one of the best ways to ensure your tomatoes get what they need. Fertilizer provides nutrients that tomatoes need for healthy growth.

It can also help to correct nutrient deficiencies, improve yield, and increase disease resistance. Fertilizers can help improve tomatoes’ taste and increase the shelf life of fruits and vegetables.

Here we’ll go over the different types of tomato fertilizers, how to use them, and when. We also provide a helpful guide on what ingredients to look for using fertilizer for your tomatoes.

What Type of Fertilizer For Tomatoes You Can Use?

Tomato fertilizers can be divided into two main categories: organic and inorganic. Let’s discuss the differences between the two.

Organic Fertilizer

Organic tomato fertilizer releases nutrients slowly over time and improves the soil quality, reducing the risk of burning plants. It also improves the structure of the garden soil, increasing its aeration and porousness. This improved garden soil structure helps the roots access to water and nutrients better.

organic fertilizer

It provides beneficial soil microbes that help to break down organic matter and improve soil health. Consequently, using an organic tomato fertilizer can help plants grow more vigorously and produce higher yields.

Organic fertilizers are a great way to give tomatoes the necessary nutrients without harming the environment. They are made from natural materials such as compost or manure.

Compost is made from decomposed organic matter, and it can provide tomatoes with a range of essential nutrients, including nitrogen, phosphorus, and potassium. It also helps to improve soil structure, making it more porous and better able to retain moisture.


Another option is to apply manure from herbivores such as cows or chickens. This manure is rich in nitrogen and other nutrients and can also help improve soil structure.

Green manures such as alfalfa or clover can be planted in the tomato patch and tilled under before planting. These green manures add nitrogen and other nutrients to the soil while also helping to improve its structure.

Inorganic Fertilizers

Inorganic fertilizers are typically made from chemicals and minerals. They can also be made from recycled materials such as sewage sludge, fly ash, and phosphogypsum.

With fertilizers, roots receive more oxygen, and drainage is improved. They also help to stabilize pH levels and prevent nutrient deficiencies. They are less likely to harbor diseases and pests than organic options.

Growing tomatoes in a home garden are relatively easy, thanks to them. When plants are growing, they require a high level of nutrients, which fertilizers can provide.

inorganic fertilizer

You need to use less of them to get the same effect as organic ones since they are more concentrated. This can save time and money and reduce the risk of over-fertilizing tomato plants. They are often more effective at promoting growth and yielding bountiful harvests.

Due to their higher concentration, they must be used more carefully than organic fertilizers. When selecting an inorganic fertilizer, choose one formulated specifically for tomatoes. It will ensure that the fertilizer contains the right mix of nutrients for optimal growth.

Using them too frequently or in high concentrations can also harm plants. They can also be more expensive and may have negative environmental impacts.

Types of Fertilizer for Tomatoes According to Basic Forms

The three main types of fertilizer are granular, liquid, and water-soluble. Each has its own advantages and disadvantages.

Granular Fertilizer:

Granular fertilizer is easy to use and can be applied directly to the soil, over roots, or mixed into irrigation water. When heavy rain or irrigation occurs, it is less likely to wash away.

granular fertilizers

It can help reduce the amount of water and fertilizer needed to maintain a healthy tomato crop. You can store it in a dry and cool place for a long time without losing its potency.

Granular fertilizers for tomatoes come in two types: quick-release and slow-release.

Quick-release formulas provide a quick burst of nutrients but can also cause burns if not used carefully. You may want to use a quick-release fertilizer to boost determinate tomatoes with a short growing season.

Slow-release formulas provide a long, steady feed that is less likely to burn plants. When growing indeterminate tomatoes, use slow-release dry fertilizers so the plants can gradually receive nutrients.

Granular fertilizer can be difficult to control the amount of fertilizer released, and it can burn the leaves of tomato plants if applied in too high a concentration.

Liquid Fertilizer:

Liquid fertilizers are quick-acting and ideal for giving tomatoes a quick shot of nutrients. You can use this method, especially if your plants show signs of nutritional deficiencies, such as yellowing leaves or stunted growth.

liquid fertilizers

Regular use of liquid fertilizer can help improve overall plant health, leading to stronger and more productive plants. It must be reapplied more frequently than granular fertilizer, which has a shorter shelf life.

You can find organic and inorganic liquid fertilizer for tomatoes in a concentrated form. The liquid should be diluted with water according to the instructions on the label before being applied to the plants.

It’s also more concentrated, so you don’t need to use as much of it. You just mix it with water and pour it around the plant’s base.


Directly apply it to plants’ roots for an immediate boost of nutrients. The effects of liquids can be mirrored with both inorganic and organic options. Water-soluble fertilizer is also available in a micro granule or powder form.

The granules are designed to dissolve quickly in water, and the powder can be mixed with water to create a liquid solution. Depending on the concentration of the fertilizer, soil can be treated directly or diluted with water before being applied.

You can also control this kind of fertilizer easily, so you won’t over or under-fertilize your tomato plants. Rainwater and irrigation water can wash it away, so you have to apply it more often than other types of fertilizer.

What is the Best Tomato Fertilizer?

You should test the soil for nutrients before you determine the most effective fertilizer. Tomato plants require fertilizer based on the soil where they will be planted. Look for a fertilizer that is high in nitrogen if the soil lacks it. The same goes for phosphorus and potassium.

Most fertilizers will have the three numbers listed on the front of the package, known as the N-P-K values. NPK stands for nitrogen, phosphorus, and potassium, and these three elements are essential for tomato plants to thrive.

NPK Fertilizer

Nitrogen helps the plant produce chlorophyll and protein essential for photosynthesis. Phosphorus promotes root growth and helps the plant produce blooms and fruit. Potassium aids in water absorption regulates the plant’s metabolism and increases disease resistance.

The best fertilizer for tomatoes contains balanced and proper nutrients of nitrogen, phosphorus, and potassium. While every plant is different, a good rule of thumb is to use a fertilizer with a ratio of 5-10-10 or 5-10-5. This will provide the plant with a good balance of all three elements.

If soil is slightly lacking in nitrogen, use a fertilizer with an NPK ratio of 10-10-10 or 8-8-8. This may not be the best NPK fertilizer for tomatoes.

While tomatoes do need all three nutrients, they tend to be heavy feeders of nitrogen. You will also find higher and lower NPK ratios in commercial tomato fertilizers, such as 12-15-30 or 4-6-3.

How to Use Tomato Fertilizers?

There are three ways to feed tomato plants: compost, granular fertilizer, and a water-based solution. Let’s discuss three methods of feeding tomato plants.

Using Compost Fertilizer:

Compost tomato fertilizers are an excellent way to provide nutrients to your tomato plants. Here are some simple steps to follow when using compost tomato fertilizers:

Step 1: Dig the soil around your tomato plant to a depth of about 10 inches. It will help your plant’s roots absorb the nutrients in the compost more effectively.

Step 2: Mix the compost with the soil, using a ratio of about 1 part compost to 3 parts soil. You can also add compost directly to the plant’s root zone by pruning back some of the lower branches.

Step 3: Water your tomato plant thoroughly after applying the compost. The roots can absorb the nutrients from the fertilizer. Repeat this process every few weeks until the plants are fully grown.

Using Granular Fertilizer:

There are two ways to use granular tomato fertilizers. When seedlings and side dressing.

Transplant Seedlings:

Step 1. Start with a dilute solution of fertilizer, mixing it at half the recommended strength.

Step 2. Give it a small amount of water to soak in. Get your transplant and plant it in firm soil.

Step 3. Feed your plant usually. That’ll feed your plant for about a month.

Side Dressing:

Step 1. Sprinkle the fertilizer around the plant, being careful not to get any on the leaves.

Step 2. Mix it in a little bit, either with your hands or with a trowel, so that it’s below the surface of the soil.

Step 3. Put a lot of water on it. As a slow-release fertilizer, it takes time for it to break down in the soil before your plants can use it.

Using Water-Soluble Fertilizer:

Soluble fertilizers act quickly and are an effective way to boost tomatoes. Here are easy steps for using water-soluble fertilizer to grow tomatoes:

Step 1: Fill a clean bucket with four or five gallons of water and add two tablespoons per gallon.

Step 2: Stir the fertilizer into the water until it is completely dissolved.

Step 3: Use a watering can or hose with a sprinkler attachment to apply the fertilizer solution to the tomato plants. Ensure to wet the leaves and stems as well as the soil around the base of each plant.

Can You Make Organic Fertilizer For Tomato Plants?

You can make homemade tomato fertilizer by mixing compost, manure, or other organic matter. This fertilizer will give your plants the nutrients they need to grow healthy and productive.

Manure is a great source of nitrogen essential for leaf growth. Compost provides phosphorus, which helps roots to grow deep and strong. Organic matter adds potassium, which aids in growing tomatoes.

homemade fertilizer

You can use the fertilizer by spreading it under the plants. Water regularly and fertilize every few weeks. With a bit of patience and care, you’ll soon be harvesting delicious homegrown tomatoes with your homemade fertilizer.

How Often Should You Fertilize Tomatoes?

Tomato plants are heavy feeders and will benefit from regular fertilization. If overdone, it can result in leafy growth rather than fruit.

You need to fertilize tomatoes when planting them. Afterward, wait until the plants are actively growing and apply a balanced fertilizer every two weeks. If you use a slow-release fertilizer, you can apply it less often.

how often to fertilize tomatoes

If you notice the leaves turning yellow, that is a sign that the plants might not be getting enough nitrogen. You should increase the frequency of fertilization.

When you apply too much fertilizer, the leaves will turn brown or black, and you should reduce the amount. If a leaf curls, it could be the result of excess nitrogen.

Once the plants begin to produce fruit, you can fertilize them every week. Apply tomato fertilizer with a lower nitrogen content so that the plants put more energy into producing fruit. You should stop fertilizing for two weeks before harvesting the tomatoes to reduce splitting.

Should You Fertilize Tomatoes When Blooming?

When using organic fertilizer, apply it during the blooming stage without harming the plants. Fertilizing during the blooming process can give your tomatoes more nutrients so they can produce more fruit.

The flower buds contain a lot of energy, and fertilizer can help to convert that energy into sugars, which are then used to create fruits and vegetables. If you are using chemical fertilizer, wait until the fruits have started to form. This will protect the leaves from chemical burns.

How much 10-10-10 Fertilizer should You put on Tomato Plants?

You should apply a teaspoon of 10-10-10 fertilizer per plant for newly planted tomatoes. Once the plants start setting fruit, you should apply three teaspoons per plant.

After that, you should fertilize every four to six weeks throughout the growing season. By following these guidelines, you can help ensure that your tomato plants get enough nutrients to produce delicious fruit all season long.

Is 10-20-10 Fertilizer Good For Tomatoes?

Whether it is good or not depends on the type of soil. You should always test your soil before adding any type of fertilizer to see what nutrients it lacks and then choose a good tomato fertilizer accordingly. This 10-20-10 radio means it has 10% Nitrogen, 20% Phosphorus, and 10% Potassium.

If your soil lacks a higher level of phosphorus, then this fertilizer would be good for tomatoes. When your soil has enough phosphorus, using this fertilizer could do more harm than good because it would encourage the plant to produce too much foliage at the expense of fruit production.

Is 5-10-5 Fertilizer Good For Tomatoes?

Using 5-10-5 radio on tomatoes is a good choice since it contains a more balanced fertilizer. The middle number in the fertilizer grade refers to the phosphorus content, which is important for promoting fruit production.

The higher potassium content also helps to encourage fruit development. Besides, the nitrogen content is on the lower side, which is beneficial for tomato plants. Too much nitrogen can result in lush green growth that reduces the productivity of fruit.

What are the Benefits of Using other Organic Natural Tomato Fertilizers?

Different organic materials can be used as natural tomato fertilizers. Some gardeners use fish emulsion or animal manures, while others use EPSOM salt, Kelp, animal manures, and compost.

Some even advocate using kitchen scraps, such as coffee grounds or organic cottonseed meals. While there is no single best way to fertilize tomatoes, organic materials have distinct advantages.

Fish Emulsion as Fertilizer:

Fish emulsion fertilizer provides valuable nutrients for plants. The nutrients in fish emulsion are readily available for tomato plants to see an immediate improvement in growth.

The product is also safe for use around children and pets. It is relatively benign and will not harm plants if used incorrectly.

When using fish emulsion fertilizer, it should be diluted before being applied to plants. It should only be used on young plants or seedlings; mature plants do not need as much fertilizer. This organic fertilizer should be applied early morning or evening when the sun is not as intense.

Animal Manures as Fertilizer:

Manure helps improve drainage and aeration in the soil, leading to healthier plant growth. It also increases the level of organic matter in the soil, which is essential for healthy plant growth.

You should only use manure from vegetarian animals like horses and cattle. Chicken manure should not be used as it can contain harmful bacteria. Manure must also be aged or composted before use, as fresh manure can damage plant roots.

Animal manure can be applied to tomato plants anytime during the growing season. But it is best to apply manure when planting tomato seedlings. This will give the plants a boost of nutrients to help them get established.

Kelp as Fertilizer:

Kelp is a type of algae that grows in cold, salty water. It is a rich source of nutrients and has been used for centuries as a fertilizer and soil amendment.

kelp fertilizer

Today, kelp is increasingly being recognized as an organic alternative to chemical fertilizers. This plant is rich in nitrogen, potassium, phosphorus, and gibberellin-like compounds that stimulate plant growth.

It is available in meal or liquid form. Kelp meal is a dry powder that can be applied to the soil around plants. Liquid kelp is usually very concentrated and must be diluted before use. It delivers a bit more powerful wallop in terms of nutrition, but both forms benefit plants.

You should apply kelp after the plants have begun to flower, either as a foliar spray or top dressing. Apply it according to the manufacturer’s directions, and you’ll be rewarded with healthier, more vigorous plants.

EPSOM Salt as Fertilizer:

Magnesium and sulfur in salt promote cell growth and assist in the absorption of other essential nutrients. Hence, tomatoes grown with EPSOM salt tend to be larger and healthier than those grown without it. The salt can help to deter pests and fungal diseases.

Epsom salt (magnesium solfate)

When planting a new tomato plant, adding a tablespoon of Epsom salt to the bottom of the hole can help to encourage strong root growth. Simply cover the Epsom salt with a thin layer of dirt, then place the tomato seedling in the hole.

Coffee Grounds as Fertilizer:

Coffee grounds provide tomato plants with many nutrients, such as nitrogen (N), phosphorus (P), and potassium (K). The soil gets better drainage and aeration, which makes the plants healthier.

It can help the soil become slightly acidic and deter slugs and other pests. Coffee grounds can help keep the area free of weeds when used around the base of tomato plants. To achieve the best results, apply coffee grounds after watering the plants and before applying mulch.

coffee grounds as fertilizer

Mix 1-2 cups of coffee grounds with a 5-gallon bucket of water, and then pour the mixture around the base of your tomato plant. Another way to use coffee grounds is to spread them around the base of the plant, which works top 2-3 inches of the soil.

Organic Cottonseed Meal as Fertilizer:

Cottonseed meal is a byproduct of the cotton industry and an excellent source of nitrogen for plants. It can help to improve the texture of sandy soils and increase the water-holding capacity of clay soils.

The meal of cotton seeds also contains minerals that are beneficial to plants, such as potassium, magnesium, and calcium. They promote foliage growth during the early stages of plant development.

Cottonseed meal

You can use it to dress tomatoes or mix it into the soil before planting. Because it is slow-release, it will continue to provide nutrients for several weeks after application.


The compost pile is an excellent source of nutrition and beneficial microbes for tomato plants. It contains a variety of macronutrients and micronutrients that are essential for plant growth.

Organic compost is better than synthetic fertilizers at gradually releasing these nutrients over time. This ensures that your plants have a steady supply of nutrition for a long period of time.

It helps to retain nutrients and water in the soil, making it more resistant to drought conditions. When transplanting your tomato plants, apply a significant amount of compost to each hole.

You can also top-dress them with compost during the growing season. This will give your plants an extra nutrition boost, helping them reach their full potential.

How Long Does Tomato Fertilizer Last?

The expiration date of a tomato fertilizer will depend on the fertilizer you use. Granular fertilizers, such as those made from a bone meal or other organic materials, can last indefinitely if kept dry.

Alternatively, liquid fertilizer will lose its potency within six to ten years once opened. The best way to store liquid fertilizer is in a cool, dark place.

Once you mix fertilizer with water, don’t store it for more than a few days. The nutrients will start to break down and become less effective. Only mix as much fertilizer as you need for each application.

You got the detailed guide on tomato fertilizers, and it’s time to get out there and start growing your own tomatoes. Just remember to give them plenty of sunlight, water, and nutrients, and you’ll surely enjoy a bountiful harvest.