How to Fix Yellow Leaves on Tomato Plants?

tomato-grown-outdoor
The spreading yellow leaves indicates the Tomato Plants growing in wrong care condition.

After graduating in Agriculture, I started my farm with my younger brother. We planted seasonal vegetables, including Tomatoes, but half of the Tomato crops died with yellow leaves.

After examining the crops, fortunately, I could revive some Tomatoes with fruit, having the first harvest. 

To fix the yellow leaves on the Tomato Plant, water on a schedule, offer full sun, and supply the soil with nutrients. Also, maintain the slightly acidic soil, help the plant overcome the transplant shock, and monitor pests and diseases. 

The leaves of tomato with some yellow leaves on the garden
Tomato Plant leaves can turn yellow due to psychological disorders or external factors like pests and diseases.

After the first attempt, I did not face any challenges growing Tomatoes.

So, if you also have happened to grow yellowed Tomato Plants, do not hesitate to read this article.

Is It Normal for Tomato Plant Leaves to Turn Yellow?

Some leaves on Tomato Plants turn yellow right after being bought from the nursery, probably due to unhealthy competition among seedlings.

You can fix that by giving your plant enough space and sunlight to grow and trimming off the damaged leaves.

On the other hand, the leaves on Tomato Plants turn yellow during fruit-bearing to shift nutrients in the production of fruits which is less of a problem.

Likewise, the leaves turn yellow and brittle at the end of their season to pave the way for another seasonal growth.

Yellow leaves of the tomato plant with some fruits hanging on it.
Yellow leaves can be a topic of concern if it appears in lumps or else the Tomato Plant is taking its course of growth.

Altogether, every yellowing has its reason behind it and can be a normal phenomenon of its lifecycle.

But if yellowing occurs in the middle of the growing season or affects the fruiting, that’s not normal.

It is a bad omen, so you must know what went wrong.

What Causes Yellow Leaves on Tomato Plants

Yellow is always a dirty fellow in Tomatoes if occurred other than normal processes that can lead to curling, spotting, and dropping of leaves.

So, you need to understand the signs of the Tomato Plant to understand the exact cause.

1. Improper Watering

As a gardener, we might mistake the watering intervals based on the spot as the water requirement of potted and garden tomatoes is different.

The plant suffers from overwatering if the soil appears soggy and waterlogged. And if the plants droop and appear weak with cracks and dryness, the plant goes through underwatering.

A bush of tomato with some dried leaves in a container
Overwater or underwater can both cause the entire wilting of the Tomato Plant.

Overwatered soil blocks the passage of oxygen to different parts of leaves, and the lack of oxygen turns them yellow.

While underwatering, the flow of nutrients from the root part gets obstructed due to the absence of water.

And the deficiency of both water and nutrients hits the Tomato leaves hard, turning them yellow.

Immediate Steps of Revival

  • Take the sick Tomato Plants out of the pot and keep them over a newspaper during overwater.
  • You can also shift the pot in the area receiving direct sunlight and let it dry.
  • If there is any mulch, remove it to allow the flow of air and light to the roots.
  • If the soil is beyond fixing, consider shifting the entire plant to new soil and removing some rotted roots, if any.
  • Move the plant into a shady place if it faces underwatering conditions.
  • Water the underwatered plants slowly from the bottom, allowing the roots to absorb it but not letting the water runoff.

2. Improper Lighting

The Tomato Plant demands light in both the fruiting and growing stages.

However, you cannot control the intensity of light that falls upon the leaves from top to bottom.

If your plant encounters a lighting problem, the plant starts to become leggy, and the stem becomes longer in the reach of light, making the bottom leaves appear pale and yellow.

tomato-plant-gone-dried
Tomatoes require shade only during the extreme summer.

In extreme light, the leaf gets sunburned, appears scorched, and ends with wilting.

Meanwhile, low light or shades hampers the normal photosynthesis process causing the lively green leaves suddenly turn yellow.

Immediate Steps of Revival

  • If you live in the USDA zone with warmer temperatures, use a shade cloth during extreme summer.
  • Remove any weeds near the plant to prevent the shade from falling upon the Tomato Plant.
  • Change the location of the potted Tomato if it is under the shade. Keep it near a southwest-facing window.
  • You can also set up grow light in case of dark rooms for at least 12 hours.
  • If you have recently bought the plant from a nursery, do not keep them directly under direct sunlight. Let the plant adjust to the change in surroundings.  

3. Fertilization Problem

Fertilizers determine the Tomato Plant’s health, but any fluctuation in fertilizer supply significantly affects the plant’s growth and resistance capability.

Yellowing leaves can exist due to the deficiency of nitrogen and potassium or micronutrients like magnesium, iron, and calcium.

tomato-leaves-in-hand
The lack of nutrients in the soil causes the Tomato to produce yellow leaves.

Besides, excess supply also turns the Tomato Plant yellow as the salts accumulate in the soil, halting nutrient absorption. 

However, deficiency affects the Tomato Plant more than excess fertilizer, causing yellow leaves.

Immediate Steps of Revival

Look at each deficiency’s signs in the table below so you can apply remedies accordingly.

NutrientsEffect on LeavesSolutions
NitrogenLower and older leaves turn completely yellow and later turns brown before dropping. Apply liquid fertilizer with high nitrogen value.
PotassiumThe margin of leaves turn yellow and then brown looking as if burned. Apply balanced all-purpose fertilizer(10-10-10).
CalciumNew leaves turn yellow leading to blossom end rot with chlorotic spots developing along the margins. Spread eggshells and apply bone meal around the tomato plant.
MagnesiumLeaf margins of older leaves turn yellow leaving the veins green and shows white to light brown necrotic dots. Apply diluted epsom salt (2 tablespoons to a gallon of water) to recover the plant slowly.
IronYoung leaves turn yellow leaving behind green veins, and older leaves nearly whitish with yellow to orange chlorosis. Apply blood meal to the soil.

But before applying the remedies, you should test the soil to know which deficiency leads to the yellow leaves.

Also, you can try applying the nutrients even before planting or apply light fertilizer every one to two weeks after they start fruit bearing.

4. Transplant Shock

Most of us start our Tomato seedlings indoors and later transplant them outdoors.

But while transplanting, most of us forget to keep a check on the fluctuation in the day and night temperature as seedlings take time to adapt.

A seedling of tomato plant with bottom yellow leaves
The seedlings show yellow leaves and recover themself, but some fall into wilting and falling off the entire leaves.

And minor negligence from our side causes transplant shock to the seedlings of Tomatoes leading to yellow bottom leaves.

The yellow leaves on Tomato Plants will not be a subject of worry if they shed themself and grow healthy leaves.

But if they do not, then revive them as soon as possible.

Immediate Steps of Revival

  • Apply a mixture of 1 tablespoon of regular granulated sugar and half a gallon of water.
  • Provide shade to the plant if it is too hot during the daytime and supply water regularly to let them overcome the shock.
  • While transplanting, check if the soil has warm and the night temperature does not drop below 50ºF.
  • Keep your hands out of the reach of the roots of Tomatoes, as they have delicate roots.
  • Trim off the yellow leaves to help the plant shift the entire focus on the growth of new green leaves instead of dying.
  • If you can do nothing, try to avoid giving any extra stress to the plant and let it recover by itself.

5. Improper Soil pH

Soil as the main base for the growth should be in its optimum health to not cause yellowing and wilting of leaves.

If any quality of the soil changes, like compaction or turning acidic or alkaline over time, your Tomato Plant will surely turn yellow.

Tomatoes grown at 4.8 pH are undersized and get ripened and less ripe if the soil is close to 5 and the 4.5-4.6 pH range respectively.

Tomato-with-yellow-leaves
Soil compaction can reduce the number of Tomatoes with yellow leaves.

Compact soil makes your Tomato roots suffocate, not allowing the flow of oxygen, nutrients, and water and ultimately causing yellow leaves.

Similarly, any change in the pH leads to infertile soil that cannot sustain the plant and causes the leaves to turn yellow and drop.

Immediate Steps of Revival

  • At first, check if your soil has turned acidic or alkaline over time by using a test kit.
  • Treat your soil with Garden lime as instructed in the packaging for highly acidic soil.
  • For alkaline soil, use organic compost to recover but do not overdo or else the compost will affect the nitrogen content in the soil.
  • Mix sands in your soil if they appear clayey and compact.

6. Common Pests

Tomatoes have several enemies starting from the seedling stage to cause the yellowing of leaves.

You might wonder if the pests only cut and make holes in the leaf, but the pests feed on the sap of leaves.

Pest is feeding on the leaves of the tomatpo making holes in the leaves.
Some of the pests in the Tomato leaves are visible, but some are difficult to spot.

Moreover, sap-sucking obstructs the water and nutrients that reach the leaves of the Tomato Plant. Due to the blockage, the leaves ultimately turn yellow and die.

The yellowing caused by pests is limited to the area they feed on, and you can check for infestation.

Immediate Steps of Revival

Here is a list of pests causing yellow leaves in Tomatoes with their signs and solutions.

Pests SymptomsSolutions
Red Spider MitesEntire leaves gets covered in webs of spider and pale shiny yellow marks on the top of the leaves and eventually turns brown.Clip off heavily affected leaves and wash the entire plant with mild soapy water.
ThripsPuncture and thin, dry brown -spotted leaves , fallen foliage with curling. Use insecticidal soap to remove them.
Potato Aphids Leaves turn yellow and later brown from top to bottom with honeydew that promotes sooty mold on foliage and fruit. Use Neem oil to control the invasion.
Flea BeetleTiny holes in the leaves that has Sievelike appearance turning them entirely yellow.Growing Chrysanthemums near the tomato plants can limit the pests.
NematodesSwelling in the roots, leading to the yellowing and wilting of leaves with stunted growth of plant.Good crop rotation can help to some extent.

You can also try washing your plants under running water and immediately exposing them to the sunlight.

By doing so, you can remove the larvae and baby of the pests and prevent infestation.

7. Bacterial and Fungal Diseases

Gardening challenges can occur when fungal or bacterial diseases fall in love with your Tomatoes.

Diseases can affect the plants from the bottom because they are primarily soil-borne. 

Leaves of the plant is suffering from yellowing and spots are in the surface of leaf.
The diseases can attack the Tomato Plant at any growth phase, but the first symptoms appear on the old lower leaves.

And it can be challenging to handle if the infestation reaches its severity. 

Immediate Steps of Revival

To start the treatment, you should know which bacteria or fungus is causing your Tomato leaves to turn yellow.

You can take the table below to understand the symptoms with their solutions hand to hand.

DiseasesSymptomsSolutions
Early Blight (Fungal disease)Irregular shaped yellow splotches in old, lower leaves

Later turns into brown spots with yellow circle
Remove the damaged leaves and spray fungicide like Bonide fungicide or other liquid fungicide.

Cover the plant with mixture of 1:5 hydrogen peroxide and water in every 3 to 4 days until the plant recovers completely.
Bacterium Wilt (Bacterial Disease)Causes V-shaped cut in the yellow leaves leading the entire plant to wilt There is no chemical cure for this disease.

The best option is to remove the entire plant and throw it in the garbage, far from the plant.
Septoria Leaf Spot (Fungal Disease)-A ring with dark brown margin , and a halo circle appears in the older leaves

Later covers the entire leaves and spreads up to stems
You can apply the same solutions as that of Early blight.
Verticillium Wilt (Fungal Disease)Yellow splotches on the lower leaves with brown veins running from the veins

Later appears as a dark brown dead spots
Unfortunately, there is no chemical or biological treatment.

The only way is to throw the infected plant into the garbage and prevent them from affecting the healthy plant.
Fusarium Wilt (Fungal Disease)Causes the plant to wilt from one side turning the leaves on the wilted side completely yellow.Like Verticillium and Bacterium Wilt, there is no cure except to prevent them from re-occurring by throwing away the affected plant into the dump.

You can also remove the debris from the previous cropping to control the diseases attacking Tomato Plants.

Should I Remove Yellow Leaves from Tomato Plants?

YES. Trailing Tomatoes turn yellow over time as a growth phase, so you can pinch and snip off the leaves.

Yellowing can damage the top leaves of the determinate type, affecting the entire plant’s growth. So you must be careful while plucking the yellow leaves. 

Follow the steps to ensure the safe removal of yellow or dead yellow leaves.

  • Look out for dry weather to cut the leaves to prevent fungus from spreading over healthy leaves.
  • Sterilize the scissors or shears with isopropyl alcohol to start the pruning.
  • Look out for the bottom yellow leaves and the leaves touching the soil.
  • Cut the bottom leaves from their lower branches but be careful not to hurt the main stem.
  • Also, you can use your fingers to clip off if the number of yellow leaves is less.
  • Throw the leaves in garbage far away from the plant to prevent fungus growth in the soil near the plant.

Look at the video if you have any confusion!

How To Prevent Yellow Leaves on Tomato Plants

You can avoid all the troubles occurring in the Tomato Plant by providing optimum care from the start.

To ensure your Tomato Plant with lush and green in its growing season, follow the steps below!

  • Provide Tomato Plants with 6-8 hours of direct sunlight.
  • Try to keep the humidity within the range of 65-85%.
  • Tomato, as a summer crop, cannot withstand frost. So keep the temperature between 21-25ºC to get the best quality fruit.
  • Maintain consistency in watering as they need water continuously without any interval.
  • Offer an inch of water weekly during the growing stage and twice a week during the fruit-bearing phase.
  • The Tomato Plant demands fertilizer during the growth stage and before the fruiting.
  • So apply fertilizer with the ratio of 10-10-10 N-P-K before the growth begins and 5-10-10 N-P-K before the fruit sets.
  • Choose a loose, sandy loam and well-draining soil with a pH of 6.0-7.0.
A person iss showing his thumb finger in front of the seedling of tomato
Tomato can grow sufficiently with mulch, such as wood chips or straw, to prevent the evaporation of water.
  • You can start pruning the leaves after the flowers have set for fruiting and follow the second and third pruning every 10-14 days.
  • Every type of Tomato can grow in pots depending on the size of the container.
  • You can transplant the Tomatoes when they attain three times the height of the container in a pot size of at least 24 inches deep and 20 inches across.

Conclusion

Tomato receives love for being the most manageable and lovable garden plant for its easy maintenance and fruit-producing ability.

But sometimes, they may trouble you with yellow leaves due to problems in the soil, light, or occurring due to diseases.

Thus, the remedies mentioned above work to revitalize your Tomato Plant.

To be free from trouble, you can choose a disease-resistant Variety of Purple Tomatoes

So love your Tomato Plants, and keep gardening!

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