How Do You Treat Yellow Leaves on Tomatillo?

Tomatillos are fruiting plants that are often grown outside in gardens. They create fruits that look like tomatoes but tend to have a more citrusy taste. Unfortunately, there are a lot of problems that can occur with Tomatillo plants. 

Some very annoying pests and fungi can cause the plants to lose their flavor or even stunt their growth. Many of these can turn a Tomatillo yellow, especially on the leaves. But issues like overwatering, too much sun, and nutrient deficiencies can also cause yellowed leaves. 

To treat yellow leaves on a Tomatillo, ensure your plant isn’t receiving too much direct sunlight, only water once per week, provide nitrogen and sulfur as fertilizer, and use neem oil for pests. If the problem is pests, there are some steps you can take first, such as spraying a milk and water mixture on your plants or using neem oil. These are safe ways to kill off pests and fungi without harming the plants.

Different yellowing patterns occur on plants that help you realize what is wrong. For example, strange and differing patterns on every leaf usually signify a bacterial or fungal infection. 

Why Are My Tomatillo Plant Leaves Turning Yellow?

When plants turn yellow, known as chlorosis, it usually means that the plant is losing chlorophyll in the leaves. Since chlorophyll is what gives plants their green color, it usually means the leaves are turning yellow or white. 

The most common reasons Tomatillo leaves turn yellow are nutrient deficiency, overwatering, and excess sunlight. While they are the most common and the most likely to be causing problems with your plants, they aren’t the only problems.

Pests and fungi can also cause issues for Tomatillo plants. The most common pest for Tomatillo plants is psyllids. They can damage Tomatillos, Tomatoes, and Potatoes. They have toxic saliva that gets into the plant when they feed.

This toxin causes a lot of harm to plants, with its most obvious sign being yellowed leaves. Usually, the Tomatillo plant will also produce smaller fruits that have a lighter skin color and less flavor. 

There isn’t much way to control these plants. Some insecticides seem to work, and sometimes a dusting of sulfur around your plant helps too. 

Fungal infections usually lead to yellowing on the leaves that don’t follow any particular pattern or distribution. Sometimes, only half the leaf will be yellow, or sometimes they will have spots. These fungal infections are usually based around the roots, so they can be hard to eliminate. 

There are quite a lot of fungal and bacterial infections that can affect plants and even Tomatillos in general. Replanting and spraying fungicide is usually a good option. You want to get your infected Tomatillo far away from your healthy plants before the disease spreads. 

However, some people find that one part of milk to nine parts water is also a good way to reduce fungus. You usually just have to spray some of it on your plant and be quick with removing any infected leaves to prevent the fungus from spreading. 

Can Too Much Sun Cause Yellow Leaves?

Sun in the sky
Too much sun can be a reason that your Tomatillo plants start to turn yellow. Usually, the leaves getting too much sun will turn entirely yellow. Eventually, the leaves will also begin to form dark-brown spots that look like scabs or burn holes, and the leaves will ultimately die. 

Most of the time, the veins will stay a vibrant green. 

What Nutrient Deficiency Causes Yellow Leaves?

Sulfur and nitrogen are the two most common nutrients where a deficiency causes yellowing leaves. 


Nitrogen deficiency can be fixed with any regular fertilizer. Loamy and sandy soils seem to lack nitrogen the most. Usually, nitrogen deficiency leads to stiff petioles and pale foliage and stems. 


Sulfur usually is similar to nitrogen deficiency. However, the leaves typically start turning yellow from the top until the entire plant is yellow. You can usually just sprinkle gypsum onto your plant for sulfur. It contains about fifteen percent sulfate, the only form of sulfur that plants can absorb. 


With magnesium, the older leaves often start to turn yellow first. The color change will usually begin at the margins and work its way inwards on the leaves. Sometimes, brown spots start forming on the veins, and the leaves twist inward. Giving your plants plenty of compost can help with any magnesium deficiency. 


Potassium deficiency affects the fruits themselves. The leaves will start to turn yellow and dry up, but the fruit will remain green at the base of the stalk. Potassium can be quickly put in the soil using a fertilizer that is rich in this nutrient. 

Do Yellow Leaves Mean Overwatering?

While yellow leaves don’t always mean that overwatering is occurring, yellow leaves on Tomatillos are the most common when overwatering occurs. 

When a plant is overwatered, they tend not to be able to absorb nutrients like nitrogen as easily and start to change color. 

Often, there is a unique sign when overwatered leaves turn yellow. Newer and younger leaves will often be fine with their standard green color. However, older leaves that are mature will start to yellow. 

Most Tomatillo plants only need to be watered about once a week and can handle about 1 inch (2.5 cm) of water a week. Drip irrigation is also an option. 

However, overwatering and nitrogen deficiency leads to very similar yellowing of the leaves. Since overwatering can cause nitrogen deficiency, it can be hard to determine which is wrong. Try to change up your watering requirements; if that doesn’t work, consider adding fertilizer instead. 

Can Yellow Leaves Be Fixed?

Yellow leaf
It is unlikely that once a leaf turns yellow, it will return to normal. It will likely stay yellow until it falls off and dies. However, you can stop further leaves from turning yellow by ensuring they have ideal nutrient levels, sunlight, and water.  

Sometimes, when the problem is nutrient deficiency, yellow leaves can change back to green, and the paleness in plants can return to normal. When overwatering causes nutrient deficiencies, the leaves can also return to normal. 

However, when a plant is sunburned, it is unlikely to turn back to its standard color. The plant usually abandons the leaf, and excess chlorophyll is taken back. The leaf then cannot produce any energy from the sun and becomes useless to the plant. 

Should I Cut Off Yellow Leaf Tips?

If only the tips of the leaves were yellow, you could keep them on your plant. However, if the whole leaf is yellow or brown, cutting them off can be beneficial. The decomposition of the leaves can attract pests, and they take more energy from the plant than they provide. 

It is recommended you let the leaf fully turn yellow before cutting it off, as that means the plant has fully absorbed all the nutrients back from the leaf. If you cut off partially yellow leaves, like leaves with yellow tips, you are taking away beneficial nutrients from the plant. 

Why Are There Yellow Leaves on the Bottom of Tomatillo Plants?

If the bottom leaves, usually also the older leaves, are turning yellow, the most common cause is due to overwatering. Overwatering usually turns the older leaves first. Ensure you only water about 1 to 2 inches (2.5 to 5 cm) a week. 


Tomatillos are delicious and a great option to grow in any garden. Unfortunately, they are susceptible to annoying pests and diseases that can make them a pain to take care of. They also don’t do well if they get too much sun or water or don’t get enough nutrients. 

To treat yellow leaves on a Tomatillo, it is important to first figure out what is wrong, such as nutrient deficiency, overwatering, or excess sunlight. Only water your Tomatillo plant once per week, provide nitrogen and sulfur as fertilizer, remove it from harsh direct sunlight, and use neem oil or insecticide for pest control.

All of these problems can lead to yellowed leaves so once you figure out the problem, be sure to act quickly so your Tomatillo can grow and thrive!