June is a big month for tomatoes. At this time they should be putting out tons of new branches and leaves, their stems should be thickening and the first flowers and fruits will appear soon. But if your tomato leaves are turning yellow this early in the season, then it’s important to discover the cause and treat the problem quickly.
Yellow leaves on tomatoes it can happen for a number of reasons. Some of these are no big deal and are easily fixed. But if others are left untreated, they could have serious effects on your plants for the rest of the season. Your harvest may be much less or even non-existent depending on the severity of the problem.
Whatever the issue, however, there is a solution. But the first step is identifying the problem. I’ll walk you through the three most common causes of yellow tomato leaves in June and how to treat each of these complications.
1. Nutrient deficiencies
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The most likely cause of yellow leaves on tomatoes in June is a lack of nutrients. Tomato seedlings often turn yellow before you even transplant them into the garden because they have used up all the nutrients built into the seeds they grew from. That’s why it’s important to fertilize tomatoes in Juneespecially if you didn’t give them a dose of fertilizer when you transplanted them into the garden.
Often the leaves turn yellow when there is a lack of nitrogen in the soil – nitrogen is what stimulates green, leafy growth. But phosphorus and potassium are also key to producing lots of fruit, so you don’t want to overdo it with nitrogen to get green leaves at the expense of actual tomatoes. Although, a potassium deficiency it can also cause yellowing on the tips of your tomato leaves.
Iron and magnesium deficiencies can also cause yellowing of the leaves in tomatoes. But instead of the whole leaf turning yellow, these nutritional problems show up in different ways. Iron chlorination causes the leaves to turn yellow and the stems to remain green. A magnesium deficiency causes the leaves to take on a yellow, mottled appearance.
The best course of action is to do a soil test first – this quick and easy at-home soil test kit from Home Depot is a great choice for immediate results – before choosing a fertilizer for your plants. A fertilizer of one size not ideal, especially if your plants are already turning yellow. A simple one soil test it will tell you exactly what nutrients your tomatoes are lacking and guide you in choosing the right plant food for your specific plants.
2. Diseases
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A variety of different ones tomato diseases can cause leaves to turn yellow. In June, the most likely diseases to affect your plants are:
- Early blight
- Late blight
- Septoria leaf spot
- Leaf mold
- Bacterial spot
- Fusarium Wilt
- Tomato necrosis
- Tomato yellow leaf curl virus
The best way to prevent both of these diseases is through proper nutrition tomato care. Do a soil test before planting and amend your soil based on those results. Water the plants at the base to prevent splashing onto the leaves, which can spread disease. Provide consistent irrigation so plants are not stressed and more susceptible to disease. When pruning tomato plantsalways clean your pruners between each plant to prevent the spread of disease.
As an extra precaution, especially if you have dealt with any of these diseases in previous years, opt disease resistant tomato varieties to grow in your garden. Botanical Interests is an excellent source for disease resistant tomato seeds. Or you can buy disease resistant tomato plants from Bonnie Plants.
3. Drift Herbicide
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Another cause of yellow leaves on tomato plants is displacement herbicidehowever, this is much less common. Still, herbicides can travel through the wind for up to a mile and damage your tomato plants, causing them to curl, turn yellow, and wilt. This issue is more likely if you live near a commercial farm, but it can occur in any neighborhood.
If you are using herbicides in your landscape, never apply them on a windy day and try to stay as far away from your tomatoes as possible. Ideally, you should pull the weeds with a tool such as Grampa’s Weeder from Walmartwhich works wonders on the dandelions in my yard. You can too try a safer organic method of weed control On the contrary, so as not to accidentally damage your plants.
Herbicides are also sometimes present in low quality soil mixes, compost and mulch. So sometimes you have to be careful when using free mulch, free compostor loose garden soil. If possible, find out the source of the material to make sure it doesn’t contain unwanted herbicides that can wreak havoc on your garden.
