Why Are My Tomato Leaves Turning White?

The problem of tomato leaves turning white is a prevalent issue affecting tomato plants. Tomato plant disease, intense sunlight, nutrient deficiencies, cold weather, and fungal diseases like powdery mildew are all common causes of silver or white leaves on tomato plants.

Mostly, these factors are responsible for the white leaf color. Tomato growers identify the cause of the issue and implement corrective steps.

Gradually acclimatizing the plants can help them recover and produce more fruit. However, younger plants typically have delicate, sparse foliage that is highly vulnerable to the intense sunlight that occurs during the middle of the day.

The tomato plant must get some indirect sunlight or morning sun so they will not have sunburn.

Fungal Diseases

If the leaves on your tomato plants are discolored in any way, mainly if they are white, brown, or yellow patches on leaves, you may have an infestation of fungus in your garden plants.

Fungal diseases are a pervasive tomato plant problem and are primary cause by over-watering the plants. Infected plants can have leaves with black borders around white dots and are easy to identify.

Some examples are root rot, Alternaria, and septoria leaf spot.

Powdery mildew is another possible culprit behind the white patches on tomato leaves. Powdery mildew on tomato plants is a contagious fungal disease that can be carried to healthy leaves by woolly aphids.

This condition affects plants and wreck havoc.

As a result, the leaves take on a powdery white appearance that quickly spreads and causes damage to plants. 

Excessive or Lack Of Nutrients

In some cases, excessive or insufficient nutrient intake may be to blame for whitening the leaves of your tomato plants. For example, tomato plants sometimes suffer from white leaves because they may lack one of the following nutrients:

• Calcium
• Magnesium
• Nitrogen
• Phosphorus

If a plant is deficient in nitrogen or phosphorus, the color of its leaves may change from green to white or yellow.

Inadequate levels of calcium or magnesium can also cause leaves to turn yellow, although the veins of the leaves will maintain their green color.

The nutrients and minerals tomato plants require can be acquired either via the use of fertilizers specifically prepared for tomato crops or by applying compost.

Low-Temperature Exposure

Tomato plants are hardy enough to withstand temperatures as low as 33 degrees Fahrenheit, but they begin to experience difficulties when the temperature drops below 50 degrees Fahrenheit.

If you leave a tomato plant outside in the cold without providing any protection, the plant may sustain significant damage, and the tomato leaves may turn white.

The tomato plant will develop white spots on its leaves if the temperature drops below what the plant considers optimal. When the temperature drops, the tomato plant will have curled leaves, which protect the plant and keep the heat.

Sap-eating insects can be found on the underside of leaves, so you have to look under the leaves and fresh foliage.

Catching pests early on, before they can cause an infestation, is the most effective method for getting rid of them. It is important to get rid of aphids and other insects and pests as soon as possible in the spring since they reproduce so quickly. 

Ways To Prevent Tomato Leaves From Turning White

The following are some preventative measures to stop the leaves on your tomato plants from becoming white.

1. Proper Hardening

It is crucial to allow tomato seedlings to acclimate to their new environment before transplanting them. Hardening involves progressively exposing tomato plants to the outside environment by removing the plants from the pot and placing them in a well-shaded place. 

Hardened leaves that were progressively exposed to outside light are less prone to suffer from sun-scald than those that have not. This can be done through proper hardening before they are transplanted outdoors.

For example, tomatoes can be hardened about two weeks before being put outside permanently to avoid damage from full sun. 

Begin by putting them in full shade for located plants indoors; they will be ready for a brief exposure to the sunlight after two to three days in the shade. Once the plants can tolerate direct sunlight, increase their daily sun exposure by 15-30 minutes every day for at least 10 days.

2. Control Fungi Growth

One of the most common causes of a fungal infection is excess water. A moist and warm environment could lead to the growth of fungus on the leaves of your tomato plant.

Keep your tomato in well-drained soil and follow the proper watering schedule.

Tomato plants require approximately one to two inches of water a week. This will prevent the roots from becoming overly wet, which is a favorable environment for the growth of fungi and fungal spores.

In addition, the plant should be kept in a well-ventilated area with plenty of light.

As an additional precaution, avoid drenching the plant’s leaves in water and instead direct the water flow into the area where the roots are located. If you have a fungus infestation, your best option is to purchase a fungicidal agent and apply it to your damaged leaves.

This over-the-counter fungicide is available from your local pharmacy.

3. Provide Proper Nutrients

White leaves on tomato plants can occur whenever there is a deficiency of calcium, magnesium, nitrogen, or phosphorus. Using a tomato fertilizer that already contains these nutrients in the ideal quantities is probably the most effective method.

You can ensure that your tomato plants are receiving all of the nutrients they require by fertilizing them with proper amounts of all-purpose fertilizer. These minerals encourage healthy plant growth and will stop the leaves of the tomato plant from turning white. 

You also want to ensure you do not give them too many nutrients as well.

4. Control Pests

Pests such as worms, flies, and mites can wreak havoc on tomato crops. For example, Aphids can spread diseases to your tomatoes, so controlling pests is essential.

It’s a good idea to introduce some beneficial insects to your garden to eliminate these pesky pests.

Additionally, a hose-mounted water jet can be used to knock them off the plants and reduce their population. Soap, neem oil, and rotenone dust are examples of organic pesticides that can be used to control these pests.