Hello,

Thank you for writing. Without photos or more details (where your plants are planted, soil makeup, watering schedule, etc.) here is some general information on leaf curl.

Note: I recommend taking a sample to your nearest Extension Office (see below for information) or to a reputable nursery in your area to positively identify the issue.

Most causes of leaf curl are stress-related. While stress is not ideal for plants, it’s usually not fatal.

Of course, watering is vital for all parts, but this is particularly true of tomatoes. The plants need plenty of water, especially for the formation of fruit. Watering incorrectly can cause stress.

Both under and overwatering can cause plant stress. Underwatering won’t allow the plant to grow correctly, and overwatering may damage the roots.

The best way to water is slowly and consistently. Do not water once a week and flood the plants. The water will likely run off and not provide enough water for the plants. Water deeply; watering deeply will help the roots go deeper into the ground. Water at the base and not overhead. Water on the leaves will evaporate and may cause fungal disease. Mulch your plants – mulch will help retain water.

Excessive heat can also cause stress. Increased heat will increase water loss. Many areas of Ohio have had excessive heat this summer. If your plants are in pots, move them to a shadier spot when the sun is high in the sky. If they are in the ground, consider installing a shade above your plants.

Too much nitrogen can also cause stress. Have you done a soil test? If not, here is some information on soil testing. If you find that your soil has high nitrogen levels, you can reduce those levels by amending the soil. Oftentimes, putting mulch in the garden will reduce nitrogen.

If you’ve recently planted your tomatoes, they may be suffering from transplant shock. It may take some time for them to get used to their new home. They will recover from them pretty quickly with some care.

If they’ve been exposed to herbicides, this may also cause leaf curl. If this is the case, you’ll want to remove the damaged leaves, or worse, the entire plant.

Lastly, your plants may have a viral infection. Again, I recommend that you contact your local Extension Office or nursery to help provide a definitive answer.

I hope this helps!