Plant Care

Tomatillo Leaves Turning Yellow? (6 Causes and How to Fix It)

There are many reasons why tomatillo leaves are turning yellow. Sometimes it’s natural and nothing to worry about, but other times you need to pay attention. Yellowing leaves on tomatillo plants could indicate something as simple as too much water or something serious, such as a pest attack that could wither your plant entirely.

Reasons Tomatillo Leaves Turning Yellow
1. Overwatering
2. Lack of Water
3. Excess or Lack of Light
4. Nutrient deficiency
5. Diseases
6. Pests

Causes of Tomatillo Leaves Turning Yellow

1. Overwatering

Yellow leaves can be a sign of a problem with the watering of the tomatillo plants and in particular of an excess of water which will cause root asphyxiation and the death of the plant soon after all the leaves have turned yellow. 

Potted tomatillos should certainly benefit from regular watering, but always wait until the soil is dry above to make a new contribution, and do not leave a saucer below the pot. 

You can possibly keep this saucer but by raising the pot, for example by placing it on another saucer placed upside down. If you think you’ve overwatered and the tomatillo leaves begin to turn yellow, remove the saucer and remove the root ball from the pot. 

You will scratch the ground around the roots to loosen them and see if they are blackened. In this case, cut just above the damaged part, repot in new potting soil.

Overwatering activates the fungi that cause root rot. These fungi generally lie dormant in the soil, becoming active only under prolonged and very wet conditions (such as excess water).

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2. Lack of Water

Another reason why tomatillo leaves turn yellow prematurely is the lack of water in the soil. Tritely improperly organized watering can lead to the fact that the leaves of the tomatillo bush become yellowed. Although tomatillo bushes are very drought tolerant, if left unattended for a long time, they will begin to turn yellow.

It is better to water tomatillo infrequently, but plentifully. The root of the bush, with the normal development of the root system, reaches a depth of up to 1 m.

This means that the plant is provided with water and nutrients from a fairly large depth, to which many other crops cannot reach. The conclusion is simple, if the tomatillos lack water, then they just need to be well watered so that the leaves stop turning yellow.

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3. Excess or Lack of Light

The leaves turn light green to yellowish if the tomatillo plants are too dark, too damp and too cold. Other indications are rapid growth and few tomatillo leaves. In the cold, the cotyledons turn yellow first. In addition, the stems are thin and brittle. For potted plants, the solution is simple when it comes to the amount of light. 

Affected potted tomatillo plants should be watered less and the soil checked for odor. In the case of smelly substrate repotting is recommended. 

Essential measures:

  • Sufficient sun
  • Protection from heat
  • Provide enough light and warmth
  • Keep shelters and greenhouses clean

Outdoor tomatillo plants or greenhouses should be placed in such a way that they are neither exposed to the blazing sun all day nor are they consistently in the shade.

It is important to remove everything that turns out to be light and heat robbers so that the tomatillo plant gets enough light and sun.

4. Nutrient deficiency

If a faulty water supply, diseases and pests can be ruled out as the cause of yellow leaves on the tomato plant, a deficiency of an important plant nutrient must be the reason for the discoloration. This is usually preceded by very loamy or very sandy soil – the pH value should be around 6.5-7 for optimal growth.

One of the equally common reasons why the leaves of tomatillo turn yellow is the nutrients deficiency of the soil. So, there may be a lack of nitrogen. If this problem is not eliminated, then over time the stem of the plant will become weak and thin, as the bush will intensively stretch upwards. 

Deficiencies of some nutrients can cause yellowing of tomatillo plant leaves. The position of the yellowing leaves on the plant and the yellow pattern can tell a lot about possible causes.

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Magnesium deficiency in tomatillo

Also results in yellowing of the leaves. Interveinal chlorosis begins near the margins of older leaves and spreads toward the center of the leaf. Brown necrotic spots may also develop between the veins of leaves showing symptoms.

With magnesium deficiency, tomatillo leaves change color to yellow in places between the veins, in addition, they can twist inward, and old leaves are also covered with grayish-brown spots. These leaves fall off.

It is permissible to replenish magnesium deficiency by foliar fertilizing with magnesium nitrate (5 g / 10 l).

Nitrogen deficiency

Causes old tomatillo leaves to turn yellow, which may drop off, while all of the foliage turns pale and the main stems and petioles become stiff. The feet no longer develop. 

A contribution of compost or decomposed manure can be made which will act on the medium term, but for a faster effect prefer a quick nitrogen fertilizer.

Potassium deficiency

A potassium deficiency is most noticeable in the tomatillo fruits themselves: they remain green at the base of the stalk. The leaves, on the other hand, turn yellow at their edges and dry up.

If the soil lacks any trace elements, then, of course, fertilizers must be added to it, which contains the missing chemical element. 

Sulfur deficiency

Symptoms resemble nitrogen deficiency, where tomatillo leaves uniformly turn yellow or pale green. In contrast to nitrogen deficiency, sulfur deficiency symptoms first appear on the upper leaves and progress to the lower leaves, until the entire plant becomes uniformly chlorotic.

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Important!
Too much plant growth resulting from too much nitrogen supply makes plants very attractive to pests.

5. Diseases

Fungal infection

Unlike nutrient deficiencies, the yellow color of tomatillo leaves that is the result of fungal disease is not uniform in its pattern and distribution over the leaf. Chlorosis can appear around leaf spots, only on one side of the plant, only on one side of the leaf, etc.

Due to the spread of the fungus, tomatillo leaves may begin turning yellow. Such infections usually hide in the ground, which means that a lot of effort will need to be made to eliminate the problem. 

Fungal infections of tomatillos can occur at any stage of their growth. A rapidly developing fungal infection can lead to yellow tomatillos leaves, weakening of the bush and poor yields. 

The fruit is not attacked. Other fungal diseases are early blight, fruit and stem rot, late blight, late blight and powdery mildew. 

The fruit infestation is different. With powdery mildew the tomatillo fruit is not affected. With all other diseases, affected fruit becomes inedible. Remove affected plant parts immediately and destroy! 

In the case of fruit and stem rot, the entire plant should be discarded to prevent it from spreading. 

It is also possible that, because it is very susceptible to diseases, your tomatillo plant has contracted some fungus or bacteria. The number of fungal diseases in tomatillo plants is huge, and that’s for another post. 

But a good recipe is to make a mixture of milk and water in the proportion of 10% milk to 90% water. (100ml of milk to 900ml of water and so on), put it in a glass and splash it through the tomato plant every other day. It’s good to remove the infected leaves so it doesn’t spread to others too.

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6. Pests

The tomatillo psyllid is the most damaging insect to potatoes, tomatoes and tomatillos. The damage is caused by toxic saliva that is introduced when the insect feeds. This can lead to a serious disease called psyllid yellows.

The presence of psyllids can be detected by the yellowing of the tomatillo leaves and buds (mosaic design), the curling, deformation or even drying out of young shoots . If we add to this the extraction of the sap, the occupied plant can be greatly weakened and its growth slowed down.

Psyllid saliva can produce a variety of toxic effects in susceptible plants, producing a condition called psyllid yellows. The color change in the leaves can be easily observed.

In potatoes these can range from shades of yellow or yellow-green (in white and russet potato varieties) to pale pink and purple (in red and blue potato varieties). A slight pink/purple color is also produced in the new shoots of the tomato plant.

Psyllid yellowing in tomatillo results in smaller fruit size. May affect fruit quality through paler skin color and reduced flavor.

Outbreaks of tomatillo psyllid infestations occur irregularly and unpredictably, so it is important to inspect plants annually for this insect to identify potential problems.

As soon as the larvae appear, remove them with a jet of water . If you observe the presence of honeydew in addition to the larvae, spray black soap diluted at 5% , as for aphids.

Insecticide options for tomato/tomatillo psyllid control are very limited. Historically, sulfur dusting was among the first effective treatments found to control psyllids, but in recent decades, it has been phased out.

The most commonly available insecticide that has good ability to control tomato/tomatillo psyllid is spinosad.

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Conclusion

So, we have listed the main and most common causes of yellowing leaves in tomatillos. It is possible that in their area, our readers observed yellowing of the leaves of tomatillos for other reasons.

As a result, tomatillo leaves turning yellow is unfortunately quite common and the variety of problems that can cause it makes diagnosis difficult. That being said, many problems can simply be avoided with the right choice, the right environment and the right growing conditions.

When not to worry about yellow leaves on tomatillo plants?

If you look at any plant, you will eventually see the older leaves wilt and die. 
Similarly, your tomatillo plant will also have yellow leaves on the bottom. This is a normal stage of the growth cycle. 

How to get rid of yellow leaves on tomatillos?

Fertilize the earth. The lack of fertilizer leaves the tomatillo leaves yellow and ends up harming the growth of your plants, so it is necessary to fertilize correctly. Offering the amount of fertilizer necessary for them keeps them healthy, so the ideal is to maintain a routine of fertilizing the land.

What to do when tomatillo leaves turn yellow?

Gardeners should examine where the tomatillo leaves are turning yellow. Lack of sunlight at the bottom of the plant can cause this problem, as the foliage needs light to produce the nutrients needed for chlorophyll. If your plant is yellowing, try moving the pot. Move it to a shady spot. The wind also influences, so if the vase is in a place with a large air current, start leaving it in a more protected environment.

Andreea Tapu

Andreea TAPU is a passionate gardener with over 5 years of experience in cultivating a wide variety of plants and flowers in her garden. As the author and creator of careofgarden.com, she is dedicated to sharing her knowledge and expertise with others, providing practical tips and advice to help gardeners of all levels achieve success and enjoyment in their gardening pursuits.