Are tomato leaves turning purple? Here is why.

Have you noticed your tomato leaves turning purple? There are many reasons why tomato leaves can turn purple. When growing tomatoes or any other type of foliage, it is important to take note of garden pests. Many times pests are not visible.

However, it is good to have some knowledge of the insects, worms, and other critters that may be feeding on your plants.

So let’s look at a tomato plant with leaves turning purple! What could cause this?

Deficiency of phosphorus

Phosphorus deficiency is one of the most common reasons for purple leaves. Phosphorous deficiency is more noticeable by the purple coloration on or around the veins. One main symptom of a phosphorus deficiency is yellowing or yellowing leaves.

If you notice your tomato leaves yellowing right before going into growth mode (which happens if you overwater), you may want to adjust your watering schedule so that more water is being conveyed to the roots.

How to combat Phosphorus Deficiency

Fertilizer should go a long way if you suspect a phosphorus deficiency. Regularly applying organic material to your garden beds can prevent nutrient deficiencies. If your soil does contain a lack of phosphorus, try using a liquid fertilizer and diluting it more for optimal results.

Deficiency of Potassium

Potassium deficiency is the most common nutrient deficiency. It is highly noticeable when the foliage turns black and the veins on the leaves start to turn purple or yellowish. 

How to combat Potassium Deficiency

If you notice signs of potassium deficiency, add more liquid fertilizer, like fish emulsion or kelp meal. You can also check the pH level of your soil to determine if soil can hold more nutrients. If you do not have access to these specific nutrients, you can test any fruits grown in your garden for Fertilizer readings. Feed tomato plants with fertilizer that is high in potassium. Choose fertilizers derived from sugar beet processing.

Cold soil temperature

Cold soil temperatures are most noticeable when plants are not blooming at their full potential. Cold soil temperatures prevent the roots of plants from absorbing any nutrients. These conditions can lead to weak, pale, or yellow-patched leaves, stunted growth, and low fruit yields.

How to combat Cold soil temperature

Remove any frost from the garden. Apply compost across the root zone of your plants to improve nutrient uptake. Cover frost with frost cloth to help protect them. In addition, Winter can reduce the ability of your tomato plant to take up phosphorus, resulting in discolored leaves. Plant tomato seedlings when soil temps reach 70 degrees Fahrenheit.

Viral infections

Viruses cause infection in plants, even when they seem healthy. Viral infections are contagious and spread easily. Without prompt treatment, your tomato plants may be affected. You can reduce the spread of viral infections by keeping your plant clean.

How to combat Viral infections

Protect tomato plants with row coversTomato spotted wilt can be prevented by removing and destroying the affected plants. Western flower thrips are impossible to control without soap, oils, and sulfur dust.

Purple leaf disorder

Several problems, including Cankers, Fungal diseases, and Diseases of the phloem, can cause purple leaf disorder. Purple leaf disorder is a problem that affects tomatoes caused by mites. These mites leave behind brown spots on your tomato leaves. After infestation, plants develop sickly tips, and leaves start turning yellow and dropping off.

How to combat Purple leaf disorder

Lower nutrient application rate stimulate plant’s immune system with high nitrogen fertilizer supply. Feed tomato plants with plenty of water during dry weather.

Insect infestation

Insect infestation is a problem that causes tomato leaf spots. The enlargement of these lesions affects the entire plant, causing premature death. In addition, insects that cause tomato leaf spot attack the roots, preventing the healthy growth of plants. Aphids are an example of a type of insect that can cause tomatoes to develop these lesions.

How to combat Insect infestation

Use less nitrogen broadcast fertilizer application rate of nitrogen is often too high for late growth to occur. Fertilize plants with nitrogen and phosphorus at the same time. Use less nitrogen fertilizer.

Shedding bottom leaves

Shedding bottom leaves is quite common for tomatoes. New leaves will grow in the next month, followed by the formation of new spurs. The stem is prevented from growing, which may lead to height loss. If the stem of the plant continues to grow vertically, then you must deal with it because it will cause a reduced yield and a shorter season.

How to combat Shedding bottom leaves

When you start tomato plants, remove the bottom leaves from the plant as it begins to mature. Leaves of the plant will sit on the wet ground. The leaves protect the plant from getting dirty. Leaves touching the ground is a common pathogen and fungus entry.

Fungus or bacteria

Infection and a condition that is characterized by small dark spots on the surface of the leaves. These spots are often dead, but they can be alive. The development of the fungus or bacteria in the infected areas causes the leaves to become pale. The contaminant can cause two types of infections:

How to combat Fungus or bacteria

Fungal and bacterial infections are common for tomatoes. These are usually treated with a fungicide or bacteria when a ripe tomato is ready for planting.

Stressed plants

When you are growing tomatoes in the greenhouse, you do not have enough space to grow more than one plant at a time. As a consequence of this, plants may become stressed and are not able to produce properly. Stress is caused by a light imbalance or lack of water or temperature.

How to Prevent Tomato Leaves from Turning Purple

Tomatoes can prevent pest and disease problems. Tomatoes are killed by a freeze or struggle to absorb nutrients from cold soil. Potassium can wash away more easily in lighter soils, while heavier soils hold naturally. Soil pH should be between 6.5 and 7.5, while calcium is critical to the successful growth of tomato plants and should be given in the form of balanced fertilizer every time you do a soil test.

The best way to fertilize tomato plants is with a balanced liquid fertilizer, but soluble fertilizer works well as long as you keep up with the application schedule.


In this article, we have mentioned some points on why tomatoes and Tomato leaves turn purple are seen. This question requires the proper knowledge and understanding of the subject for a proper answer. We have described the common defects in tomato plants and their cause. In this article, we have given some tips on how to stop tomato leaves from turning purple and also mentioned the remedies for this problem. So there is no doubt that tomatoes are very important. I hope you learned something new about tomatoes; and that, with this knowledge, you will be able to grow a better crop. If you have any questions about this article, please ask.