Is 13-13-13 Fertilizer Good For Tomatoes?

Is 13-13-13 Fertilizer Good For Tomatoes

Fertilizer is a key component in the growth and productivity of vegetable plants. One of the varieties of fertilizers you can use to increase the fertility of your gardening soil is the 13-13-13, also called the triple 13 fertilizer. Being a tomato farmer, you may have this one question.

Is 13-13-13 fertilizer good for tomatoes?

13-13-13 fertilizer is good for tomatoes. It’s helpful for kick-starting the growth of tomatoes after the winter. Apply 10lbs/1000 sq ft and top dress your lawns with 7lbs/1000 sq ft, every 8 – 10 weeks.  Even so, triple 13 catalyzes the falling off of the first and second blossoms cluster. 

This article explores the impact of fertilizer on tomato growth, with more emphasis on the triple 13 variety.

ALso Check: Green Goo In Tomatoes

Is 13-13-13 Fertilizer Good For Tomatoes?

Triple 13 fertilizer is good for tomatoes because of the vital nutrients it adds to your soil, enhancing the healthy growth of the plants. Below are the nutrients that the fertilizer offers to your tomato plants. But before that, let’s define this fertilizer.

What Is 13-13-13 Fertilizer?

13-13-13 fertilizer is a balanced soil dressing containing equal amounts of the necessary nutrients of the soil. 

These vital nutrients include nitrogen, phosphorus, and potassium. Triple 13 contains 13 percent of each of these vitals. They’re the primary nutrients that enhance the proper growth of your tomato plants. 

The core purpose of triple 13 fertilizer is to jump-start your tomatoes during the first months of spring, from the dormancy of winter. The proper application of a balanced fertilizer helps maintain healthy and attractive plants. As a result, you establish forms of landscaping such as lawns.

Why Use 13-13-13 Fertilizer For Your Tomato Growth?

You use 13-13-13 for your tomatoes because of the essential nutrients it adds to the soil. As earlier mentioned, triple 13 fertilizer derives its name from the number of micronutrients it carries. This fertilizer contains nitrogen, phosphorus, and potassium in equal portions of 13%. Hence the 13-13-13 N-P-K ratio. Let’s look at each of these vitals.


Nitrogen (N) is a key micronutrient your tomatoes need, to offer you a good return. It facilitates the synthesis of proteins, amino acids, nucleic acids, chlorophyll, and co-enzymes. Tomatoes require this nutrient more than any other.

Your soil may be having a substandard amount of nutrients and the tomato plants can’t manufacture them on their own. That is where Tripple 13 comes in! It contains 13% of nitrogen.

According to research, a lawn needs 1lbs/1000 sq ft of a 20% nitrogen content fertilizer. Hence, because Triple 13 contains 13% of nitrogen, you need 7.7lbs per every 1000 sq ft lawn.

If you supply the right amounts of this nutrient for your tomatoes, they grow healthy and produce more fruits. On the other hand, inadequate supply leads to the yellowing of your plants, from bottom leaves upwards. Even so, don’t overdose your plants with the Triple 13 fertilizer! 

Excess nitrogen results in bushy, green tomato plants with very low yields. 


Phosphorus (P) is an essential nutrient that converts other nutrients into a usable form (nucleic acids and proteins building blocks). The converted nutrients enhance the growth of your plants. 

Triple 13 contains 13% of phosphorus, making it a reliable source of this nutrient. Your tomato garden needs 150lbs per 43,560 sq ft of nitrogen. It’s beneficial to your plants in various stages, differently.

Here is how:

  • Initial/establishment stage: Nitrogen maximizes the root development of the plants
  • Vegetative stage: It ensures continuous growth
  • Flowering(fruit set) stage: Enhances fruit development
  • Maturity stage(fruit ripening) stage: Boosts the nutritional quality of the tomatoes


Potassium (K) is the nutrient that ensures water status and water balance in a plant. It’s responsible for the production and transport of sugars, activation of enzymes, and protein synthesis. In tomatoes, potassium has an additional function which is pigment synthesis.

Triple 13 N-P-K ratio indicates 13% of potassium nutrient. Your tomato plants need 225lbs of this nutrient per 43,560 sq ft. Here is how they benefit from potassium.

  • Initial/establishment stage: Promotes healthy early growth of your plants
  • Vegetative stage: Maximizes the leaf tissue concentration in preparation for flowering
  • Flowering(fruit set) stage: Ensures growth continuity and increases the number of flowers.
  • Maturity (fruit ripening) stage: Minimizes disorders.

Potassium maintains the healthy status of your tomatoes during harsh conditions such as drought and extreme cold. It also makes them disease resistant.

 Is Triple 13 Good For A Vegetable Garden?

Yes, triple 13 is good for a vegetable garden. It’s a multipurpose gardening fertilizer that you use on your flower beds and lawns. This fertilizer is also excellent for planting shrubberies, pruning hedges, and patches, planting trees, and in vegetable gardens. 

Moreover, the impact of 13-13-13 fertilizer on your plants is noticeable within a short time. However, you need to re-apply it within 8-10 weeks for the best results. This fertilizer is complete, balanced, and ideal for starter crops.

How Do You Use A 13-13-13 Fertilizer For A Vegetable Garden?

The use of a 13-13-13 fertilizer for a vegetable garden depends on plant type and its different stages.  Below are some of the major directions.

  • Standard pre-planting directions: 1/2 lbs in every 25 feet row. You should apply it into 4-6 inches of the topsoil and water it.
  • Peppers and Tomatoes: ½ lbs on a 25 feet row by the plants’ side, after blossom.
  • Peas, Beans, and Corn: ½ lbs in every 25 feet row, for 10-12 inches tall plants.

Signs of Tomato Over-Fertilization

Although lack of enough nutrients in the soil may cause poor growth and inability to withstand diseases, over-fertilization is worse. It leads to the spotting of your plants or even death. Here are some indicators of excessive application of fertilizer in your tomato garden.

Leaf yellowing: Excess nitrogen in the soil lowers the rate of water absorption by the plant. As a result, your older tomato leaves start turning yellow before time. 

Bushy leaves and slow flowering: Nitrogen-saturated soil produces bushy plants with very few flowers. The flowering takes extraordinarily long.

A skin of matter on the ground: Heavy build-up of stuff and fungi may start growing at the top of the soil surface.

Lower leaves wilting and yellowing: Too much fertilizer can lead to the withering and yellowing of the bottom leaves due to the lack of sufficient water supply in the plant.

The unanticipated loss of leaves: Your tomato plants may lose all their leaves at once.

Remedies For Over-Fertilization Effect 

Although the impact of excessive application of fertilizer can be severe, there are several ways of fixing the issue. They include the following.

  • Spreading mulch: The major catalyst of the decaying is nitrogen. Hence, if you spread mulch (preferably sawdust) on the soil, it reduces nitrogen content. To fasten the process, mix the sawdust with soil instead of spreading it on the surface.
  • Disposing of the build-up: You should scrap off and dispose the skin of matter that forms on the soil surface immediately after you notice it.
  • Flushing/leeching of soil: Soak the plants with a lot of water.


What Is The Best Fertilizer For Growing Tomatoes?

A high-phosphorus fertilizer is best for growing tomatoes. Get any tomato-formulated fertilizer with a high middle number in the N-P-K ratio. Be sure to apply the right amounts though.

What Is The Best Fertilizer Number For Tomatoes?

The best fertilizer number for tomatoes is a balanced N-P-K ratio or one where the ‘P’ is higher than the ‘N’. Our focus fertilizer is a perfect example with a 13-13-13 ratio. Also if you have a fertilizer with a 2-3-1 ratio, it’s also an ideal choice. 

How Do I Know If I Need To Add Fertilizer To My Soil?

You know that you need to add nitrogen to your soil if you notice the stunted growth of your plants. Nitrogen is responsible for the division and enlargement of cells. Hence, its shortage slows down the growth and development of your plants.  

Do My Tomato Seedlings Need Fertilizer?

Yes, your tomato seedlings need fertilizer. You should fertilize your seedlings once they attain a height of  3 inches. Re-apply the fertilizer in intervals of one week until transplanting time. The nitrogen in the fertilizer promotes the growth of the stem and leaves. 

Does Triple 13 Fertilizer Break Down?

No, triple 13 fertilizer doesn’t break down. If you store it properly, it won’t deteriorate. Fertilizer consists of several natural minerals and elements that won’t break down no matter how long you store it. Proper storage involves retaining it in the original bag or container and placing it in a dry environment to avoid moisture absorption.


13-13-13 fertilizer is good for your tomatoes. This fertilizer is complete, balanced, and fast-acting. It contains 13% of Nitrogen (N), Phosphorous (P), and Potassium (P). These nutrients are essential for the well-being of your tomatoes from germination to maturity. 

Nitrogen enhances the synthesis of vital nutrients such as proteins and amino acids. Phosphorous converts other nutrients into a usable form. Plus, Potassium ensures excellent water status and balance in the plants.

Therefore, if you use the right quantities of triple 13 fertilizer, you’ll grow healthy tomatoes and increase your yields.