Chow Line: Excess rainfall impacting tomato plants

Discolored leaves such as this, suggest fungal disease in this tomato plant. The leaves need pruned with sterilized pruners and then discarded into the garbage and not the compost pile. Photo curtesy of Timothy McDermott.

I’ve grown tomato plants in my central Ohio backyard for the past couple of years, as part of my efforts to make healthier food choices for my family. But this year, the leaves on the tomato plants are discolored and dying. What’s going on with the plants, and can my tomatoes be saved?

It’s wonderful that you are making healthy food choices for your family. Tomatoes are excellent sources of vitamins A, C, and K, and potassium and folate. The tomato is also a wonderful source of the antioxidant lycopene, which has been linked to several important health benefits such as reducing your risk of heart disease and some types of cancer, as well as helping you maintain a healthy blood pressure.

Without having seen your specific tomato plants, I can offer some suggestions of what you can do to possibly address the issues occurring in your backyard garden.

Due to the historic rainfall the region has experienced this year, it’s likely that your tomatoes have been impacted by too much moisture.

Tomatoes can suffer several problems related to heavy rainfall, which can shorten their harvest period and affect their yield, said Timothy McDermott, educator, Ohio State University Extension. OSU Extension is the outreach arm of The Ohio State University College of Food, Agricultural, and Environmental Sciences.

There are, however, a few things that backyard growers, community gardeners, and urban farmers can do to keep their tomato plants healthy and productive through heavy rain periods, McDermott wrote in a recent blog post.

Mulch can be used as a barrier to keep soilborne fungal spores off of lower tomato plant leaves. You can use organic or nonorganic mulch, placed around the base of your plant.

You can also prune the lower leaves of your tomato plant to minimize lower leaf contact with soil, McDermott wrote.

“Pruning promotes air circulation,” he said. “But when pruning, use sterilized pruners to remove any diseased leaves, and put diseased leaves in the garbage, not the compost after pruning.”

Also, take note of any fertility issues that your tomato plants might be facing due to heavy, excessive rainfall, such as what the region has faced this year.

“Constant rainfall can leach fertility from soil, making it unavailable to the plants,” McDermott said. “Make sure you monitor your plant’s growth and health carefully to avoid a nutrient deficiency. 

“Foliar feeding can be used when the ground is too saturated to irrigate with water-soluble fertilizer.”

McDermott also cautions that you monitor your tomato plants for signs of blight, removing any affected leaves when you see them.

Chow Line is a service of The Ohio State University College of Food, Agricultural, and Environmental Sciences (CFAES) and its outreach and research arms, Ohio State University Extension and the Ohio Agricultural Research and Development Center (OARDC). Send questions to Chow Line, c/o Tracy Turner, 364 W. Lane Ave., Suite B120, Columbus, OH 43201, or

Editor: This column was reviewed by Timothy McDermott, educator, OSU Extension.

Tracy Turner
For more information, contact: 

Timothy McDermott
OSU Extension