Some over-fertilized trees of tomatoes with yellowing leaves and wilting stems.

Over-Fertilized Tomatoes SOS: Diagnose & Fix It Now!

Over-fertilized tomatoes can cause various problems, such as leaf burn, stunted growth, reduced fruit quality, and increased pest and disease susceptibility.

To fix over-fertilized tomato plants, you need to do the following our experts provided steps.

Tomatoes are among the most popular and rewarding crops to grow in your garden. They are versatile, delicious, and nutritious. However, they also require some care and attention to thrive.

One of the most common mistakes that gardeners make is over-fertilizing their tomato plants. This can cause issues like lower fruit quality, more pests and diseases, and even plant death. In this blog post, we will explain how to diagnose and treat over-fertilized tomatoes and share some expert tips on how to prevent this issue in the future.

How to Diagnose Over-Fertilized Tomatoes

The first step to treating over-fertilized tomatoes is to identify the signs of over-fertilizing. Here are some of the most common symptoms to look out for:

  • Yellow or brown leaves may mean the plant has too much fertilizer, causing nutrient burn. The leaves may also curl, wilt, or drop off.

A tomato plant with yellowing leaves, which is a common symptom of over-fertilization.

  • Stunted or spindly growth:ย  The plant is not getting enough light, water, or oxygen due to excess fertilizer. The plant may also produce fewer or smaller fruits or none at all.

Young tomato plants with slender stems and sparse leaves, indicating potential over-fertilization, grow in blue pots.

  • Cracking or splitting of fruits: This can indicate that the plant is experiencing rapid growth spurts, followed by drought stress, due to excess fertilizer. The fruits may also taste bitter or bland or develop blossom end rot.
Tomato Fruit Cracking Problem

Symptoms of Tomato Fruit Cracking. Image: SAU

  • Salt accumulation on the surface of the soil: This can indicate that the soil is becoming too saline due to excess fertilizer. The salt can damage the roots and reduce the plant’s ability to absorb water and nutrients.

If you notice any of these signs, you should check the soil pH and the amount of nitrogen in the soil. You can use a soil test kit or a digital meter to do this.

Ideally, the soil pH should be between 6.0 and 6.8, and the amount of nitrogen should be between 150 and 200 ppm.

If the soil pH is too high or too low, or the amount of nitrogen is too high, you have over-fertilized your tomatoes.

How to Treat Over-Fertilized Tomatoes

The next step to treating over-fertilized tomatoes is to correct the soil condition and restore the plant’s health. Here are some of the best ways to do this:

  • Flush the soil with water: This can help to leach out the excess fertilizer and salt from the soil. You should water the soil deeply and slowly until the water runs out of the drainage holes. You may need to repeat this several times, depending on how much fertilizer you have applied.
  • Add organic matter to the soil: This can help to improve the soil structure, drainage, and aeration and provide some beneficial microorganisms and nutrients to the soil. You can use compost, manure, peat moss, or leaf mold to do this. It would help to mix the organic matter with the top few inches of the soil to avoid disturbing the plant’s roots.
  • Prune the damaged parts of the plant: This can help remove the dead or diseased leaves, stems, and fruits and encourage new growth. It would help to use clean and sharp scissors or pruners to do this and make clean cuts at an angle. It would help to disinfect your tools after each use to prevent any infection from spreading. For more details please read our expert tips on How Do You Prune Tomato Plants For More Yield.
  • Apply a balanced fertilizer: This can help replenish the nutrients that the plant needs and restore the balance of the soil. You should use a fertilizer that has a low or equal ratio of nitrogen, phosphorus, and potassium, such as 5-5-5 or 10-10-10. You should also follow the label instructions on how much and how often to apply the fertilizer and avoid overdoing it.

How to Prevent Over-Fertilizing Tomatoes

The best way to prevent over-fertilizing tomatoes is to follow some simple guidelines on how to fertilize your tomato plants properly. Here are some of the most important tips to remember:

  • Test your soil before fertilizing: This can help you determine your soil’s current condition and what nutrients it needs. There are three methods to check your soil. You can use a test kit, or a digital meter, or send a sample to a local extension service for analysis. You should test your soil at least once a year, preferably in the spring or fall.
  • Choose the right fertilizer for your tomatoes: This can help you provide the optimal nutrients for your tomato plants and avoid any nutrient imbalances or deficiencies. Use a tomato or general fertilizer with equal amounts of nitrogen, phosphorus, and potassium, like 5-5-5 or 10-10-10. Look for a fertilizer with calcium, magnesium, iron, and zinc. These nutrients are important for tomato growth and quality.
  • Apply the fertilizer at the right time and rate: This can help you avoid over-fertilizing or under-fertilizing your tomato plants and ensure a steady and consistent supply of nutrients. Follow the label instructions for fertilizer and change the amount and frequency based on plant growth and soil condition.
    • As a general rule, you should fertilize your tomato plants once every two weeks, starting from when they are transplanted until they start to flower. You should then reduce the frequency to once every four weeks until the end of the season. You should also apply the fertilizer about 6 inches away from the base of the plant and water it well.


Over-fertilizing tomatoes is a common and avoidable mistake that can harm your tomato plants and reduce your harvest. Use these tips to fix over-fertilized tomatoes and avoid the problem in the future. Remember, less is more when it comes to fertilizing tomatoes.

Don’t let over-fertilization ruin your tomato harvest! Follow these tips to diagnose, fix, and prevent issues. Start growing healthier tomatoes today!

Sources and References


I am Gaushoul Agam

๐‚๐จ-๐…๐จ๐ฎ๐ง๐๐ž๐ซ & ๐‚๐„๐Ž

I am an experienced Horticulture Officer in the Department of Agricultural Extension in Bangladesh. I am committed to improving agriculture and farming.

I created ToAgriculture to address global food safety concerns. These concerns are caused by a growing population, diminishing farmland, and the impact of climate change on agriculture. I assist readers in learning modern farming techniques.

I also help them control pests and diseases. Additionally, I guide managing agriculture sustainably. All of this is aimed at creating a better and more successful future in farming.

I have experience in field crops and horticulture crops. I know about fruit and vegetable farming, managing pests and diseases, irrigation, and grafting. Come with me as I share my knowledge and experiences to help you create a better future.

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