Tomato Plant Turning Yellow – What To Do?

Several factors can cause the yellowing of tomato leaves. It is natural and should not be a source of concern, but you must pay attention at all other times. Yellowing tomato leaves could suggest anything from too much water to something more dangerous, such as a pest invasion that could turn ugly.

Under or over-watering, nutrient deficiencies, and pests or diseases spread by pests are just a few of the variables that might cause your tomato leaves to turn yellow.

Some of these are simple to correct, while others may be more difficult to identify and cure. In many occasions, the plant can’t be saved, and you need to remove it from your garden to prevent the disease from spreading.

tomato leaves

In our guide, you can learn why you have yellow leaves on tomato plants and how to fix the issue.

By the end, you’ll be able to put an end to tomato plant yellow leaves and reap healthy crops. (Read White Spots On Tomato Leaves)

Why Are My Tomato Plant Leaves Turning Yellow?

Here are a few of the reasons you have yellow tomato leaves. Most of these can have tomato leaves turning yellow, yet not all of them have an easy cure if you can stop the leaves from turning yellow at all.

First Tomato Leaves

The cotyledons or the first leaves) on tomato, seedlings are not real leaves. Their primary purpose is to feed the seedlings until real leaves develop so they can begin photosynthesis. True tomato plant’s leaves are the second set of leaves.

Solution: When tomato leaves turn yellow at this stage, they can fall off. However, it is only the yellow leaves on tomato plants that are the cotyledons. You are safe to remove these yellow tomato leaves so the others can thrive.

Transplant Shock

Transplant shock occurs when tomato seedlings are moved into larger outdoor containers or the ground and are common tomato plant problems when moving young tomato plants from warm indoor environments to cooler outdoor areas.

After a week or two, the plant’s green leaves wilt, and tomato leaves turn yellow. If your plant’s newer leaves are bright green and growing, but lower leaves are pale yellow, it’s recovering from transplant shock.

To revive transplanted tomato seedlings and help them recover from transplant shock, use 1 tbsp ordinary granulated sugar with 1/2 gallon water. Although not proved, this method is popular among home gardeners when growing tomatoes. (Read Life Cycle Of Tomato Hornworm)

Early Blight

If the yellow leaves on the tomato plant represent early blight, take action quickly before the plant is destroyed. Remove the afflicted leaves and dispose of them.

Cover the plant with mulch and spray it with Bonide Liquid Copper Fungicide or any other Copper Fungicide.

Another approach is to spray the entire leaf, and the entire plant with Hydrogen Peroxide water (5 parts water/1 part hydrogen peroxide) every 3-4 days till the plant improves.

To prevent this, practice crop rotation and don’t plant the same crops in the same soil for two years.

Spray your tomato plant with Neem Oil Spray every 14 days to prevent most bacterial and fungal diseases.

Bacterial Wilt

The bacterium Ralstonia Solanacearum causes leaf yellowing, where it prefers sandy, moist sandy soils near the coast.

Planting time is where the bacterial disease affects tomato plants should the root system be harmed while transferring seedlings, and microorganisms invade the plant. Affected plants won’t produce tomatoes until mid-summer when leaves are yellow and the plant wilts.

Yellow leaves get V-cuts. The plant wilts in a few days. Luckily, you can get tomato varieties that are resistant to such diseases.

The tomato plant dies suddenly in hot, moist weather. Cooler temperatures and drier soil conditions reduce bacterial wilt symptoms and plant mortality.

Unfortunately, there is no cure for Bacterial wilt, and should your plant be affected. Remove the plant promptly, dispose of it in the garbage, and ensure the affected leaves don’t touch other plants.

tomato seedlings

Septoria Leaf Spot

Septoria leaf spot is another disease that causes yellow leaves on tomato plants and is caused by soil fungus. Septoria leaf spots starts as a yellowish circle on the undersides of older leaves at the plant’s base. The rings will be dark brown spots with a tan core and a yellow halo.

The irregularly shaped yellow splotches grow larger until they cover the once vibrant green leaves and then go on to the plant stem. The yellow leaves will fall off the plant by exposing the maturing tomato fruits to the full sun. After the leaves fall, the plant stops producing and maturing tomatoes.

Verticillium Wilt

Common in chilly climates where the soil doesn’t warm until mid-summer. Despite the illness, the plant does not wilt until the tomato plant is mature and the tomatoes are ripe.

There are yellow splotches on the bottom leaves of verticillium wilt with brown veins extending out from them. The plant leaves will, after that, develop dark brown dead patches.

The yellow spots resemble early blight, but verticillium wilt does not develop bull’s-eye rings around the splotches. After the leaves fall, the plant becomes stunted and unproductive.

Unfortunately, no chemical-based or organic treatment is available for Verticillium wilt, so remove the affected plant and dispose of it in the garbage.

Fusarium Wilt

Yellow leaves on tomato plants are commonly caused by a soil-borne fungus called Fusarium oxysporum. With Fusarium wilt, only one side of the plant wilts.

The wilted, yellowing leaves turn yellow, and plant growth is limited. The plant disease often begins at the stem’s base and spreads to the branch, leaves, blossoms, and tomatoes. Fusarium wilt occurs in warmer regions as soil and air temperatures exceed 80°F (29 C).

Treating fusarium wilt isn’t possible, and, like other forms, you need to dispose of the plant to avoid the spread of these tomato plant diseases. As with any wilt, avoid overhead watering.

End Of the Growing Season

The leaves of tomato plants naturally turn yellow as the gardening season ends. Less daylight and cooler nights. The chilly weather notifies the plants that harvest is over.

Yellowing tomato leaves and reduced tomato output are symptoms of impending autumn. If your plant still has some unripe tomatoes, you can assist them in ripening by:

  • Trimming yellow leaves and fresh flowers.
  • Also, stop watering and feeding the plant, focusing on ripening the season’s last tomatoes.

The curly top virus is another disease and should be treated as with all the above.

Should I Remove Yellow Leaves From Tomato plant?

If the yellow leaves on the tomato plant are because of cold temperatures, nutritional issues, and stunted growth, removing some of the plant leaves will help it cope. The plant can use the energy to support the other leaves and fruits.

Yellow on tomato plants leaves show bacterial or fungal disease. Remove dying leaves and dispose of them. Don’t compost, and before using gardening scissors to remove infected yellowing leaves, sterilize them.

tomato plant

Can You Save a Tomato Plant With Yellow Leaves?

Yellow leaves on tomato plants show not enough sunlight. Even though the plant is in full light, the lower leaves may be insufficiently lit, it causes leaves to turn yellow, and eventually drop. Some lower leaves will turn yellow and die to provide enough light for the rest of the plant and developing plant.

Make sure the tomato plant receives 8 hours of sun per day. Some cherry tomato plants can survive with only 6 hours of sunlight, but most large-fruited tomatoes need 8 hours.

Around the tomato plant, make sure it is free from weeds and other plants to allow sunlight to reach the plant’s interior sections. (Read Are Coffee Grounds Good For Tomato Plants)

Plant on the north side of a raised bed to avoid shadowing other plants and locate your raised bed away from trees and structures to avoid shade in sunny and hot weather.

Nitrogen Deficiency

Plants require nitrogen for above-ground growth. A nitrogen-rich soil is required for optimal plant growth and tomato output in tomato plants.

In nitrogen-deficient soil, older plant leaves turn pale yellow. The plant’s growth and production will cease once the upper leaves turn bright yellow. Adding fish emulsion can help deliver nutrients for many areas of shortage.

Iron Deficiency

When the soil does not provide tomato plant’s young leaves turn yellow at the base. The yellow extends up the leaf veins, giving the leaf a web-like look.

The iron-deficient plant’s leaves will turn pale yellow leaves and fall off. After leaf drop, the plant is dormant.

You can apply a Liquid Iron supplement to your tomato plant for a quick treatment. It can be sprayed on foliage or added to the soil. Follow the package directions and repeat if necessary.

What Are The Signs of Over Watering Tomato Plants?

Tomato plants demand a lot of water during the growing season and probably most out of your vegetable plants in your vegetable garden. Over-watering will drown the plants and cause yellow leaves on tomato plants.

Over-watering makes the soil wet, leads to compacted soil, and restricts oxygen flow. The plant progressively drowns as the leaves turn yellow from a lack of oxygen because of soil compaction.

If a layer of mulch sits on the soil around the tomato plant’s base, carefully remove it for a few days, and allow sunlight and airflow to reach the soil.

A thirsty tomato plant will initially wilt, then grow yellow leaves. Wilting is a plant’s first sign of dehydration. The yellowing of the leaves shows water. The leaves will first turn yellow at the edges. Then the leaf turns yellow and falls off the plant. (Learn When To Fertilize Tomatoes)

Water the tomato plant every other day in the morning, avoiding wetting the leaves. If needed, use a water meter to check soil moisture. Install drip irrigation.

Over-watered tomato plants can recover quickly from yellow leaf and then thrive. Watering your tomatoes correctly can help stop blossom end rot once your plants are bearing fruit. Root rot is also an instance of too much water.

Tomato Plant Turning Yellow - What To Do (1)

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