Tomato cultivation is just in full swing, and already the first tomatoes ripen. However, this does not mean that all the problems with the plant are over. If suddenly the tomato gets yellow leaves, it may have different reasons. What are the most common causes and what can be done to not jeopardize the tomato harvest, read below.
Table of contents
- The most common causes at a glance
- Why does my tomato get yellow leaves?
- Can you still eat the fruit if the tomato gets yellow leaves?
The most common causes at a glance
When tomato leaves turn yellow, it can be due to a variety of reasons. Both pests and diseases can be to blame. In many cases, however, it is a deficiency symptom that can be remedied with the right care.
Why does my tomato get yellow leaves?
As a rule, the yellowing of the leaves is due to the lack of the pigment chlorophyll. When it is not sufficiently formed, the leaves turn yellow. One of the most common reasons for this is incorrect watering. Both too much and too little water can harm the plant, so it is crucial that you water your tomatoes properly.
Even with proper care, the leaves of the tomato plant can discolor. Yellowing is a common symptom of various diseases as well as pest infestation. In rare cases, a lack of nutrients can also cause tomato leaves to turn yellow and fall off.
Important: You should always remove yellow leaves from tomatoes when they are below the first inflorescence.
Now let’s take a closer look at the various causes of discoloration and tips on how to eliminate the problem.
Tomato gets yellow leaves because of improper watering.
Tomatoes need regular watering to thrive. While the plants can be forgiving of small watering mistakes, watering them incorrectly can cause them major damage and even lead to crop failure. Whether you water too much or too little, discoloration of the leaves is often a sign of improper watering.
If the substrate is too dry, the leaves turn brown and fall off, while overwatering leads to yellow leaves. Because of the excessive moisture, waterlogging occurs and the roots begin to rot, preventing them from transporting nutrients to the plant.
There is no perfect recipe for how much water a tomato needs , but a good rule of thumb is to perform a moisture test by sticking your thumb several inches deep into the soil to check for moisture near the roots. If the soil feels dry, it’s time to water, and the closer tomato plants get to full maturity, the more water they need. It’s even better to buy a soil moisture meter and use it regularly as a guide for watering.
Tomato diseases that cause yellow leaves.
Often a tomato will get yellow leaves if the plant is suffering from a disease. Both leaf spot disease and bacterial wilt can cause yellowing of tomato leaves. If this is the case, then action must be taken as soon as possible to prevent the plant from dying out and infecting other plants as well.
In the case of leaf spot disease, the leaves turn yellow and get gray spots and black dots. If the infestation is still small, then remove the infected leaves, spray the plant with milk and weed it. If more than half of the plant is infected, then it can not be saved and you need to remove it.
Bacterial wilt leads to the fact that the tomato leaves turn yellow from the bottom and shoots brown-yellow webs. If the tomato disease is detected early, then save the plant by removing the infected leaves, loosen the soil and provide the plant with fertilizer . If the infestation is larger (more than 1/3 of the plant), it must be completely destroyed.
Important: Infected leaves do not belong on the compost!
Discoloration due to lack of nutrients
The lack of nutrients can also be a cause of yellow leaves on tomato plants. Tomatoes are heavy feeders, which means the plant needs twice as much fertilizer as a cucumber and even four times as much as beans.
If the plant does not receive enough nitrogen, the older leaves will begin to turn yellow, and in many cases they will fall off as they provide their nitrogen for the younger leaves to survive.
The yellowing of the leaves can also be the result of an iron deficiency, but this is most noticeable in the youngest leaves. A magnesium deficiency, on the other hand, results in yellowing that looks more like speckles or spots on the older leaves.
These three – nitrogen, iron and magnesium – are the most common nutrient deficiencies that amateur gardeners should look out for in yellow leaves and fertilize regularly. It should be remembered that if the plant is receiving a lot of fertilizer, it will also need a lot of water.
What pest can cause yellow leaves in the tomato?
If the tomato has been attacked by whitefly or thrips (also known as thunderflies), it usually reacts with yellow leaves. To prevent whitefly infestation, you can protect the plants outdoors with insect netting and possibly place yellow boards near the plants. If the plant is infested with thrips, spray it with soft soap solution and spread primeval rock flour on the soil.
Can you still eat the fruit if the tomato gets yellow leaves?
In most cases, if a lush tomato with many fruits gets yellow leaves, this is not a reason not to enjoy the fruits. Only in the case that the plant has been affected by a disease such as bacterial wilt, the tomatoes become inedible and must not be eaten.