We've had several customers come in with tomato plants that have been damaged by herbicides. Usually, the culprit is a 2, 4-D weed killer that has drifted from another yard. Tomato plants are highly sensitive to herbicide exposure and the result is twisted, curling leaves. The only remedy for this is patience. Growth will stop for a few weeks, then resume as the plant recovers. If the plant is seriously affected (more than half) consider replacing it with a healthy plant. The herbicide will wash away after a couple rains and will not affect the fruit produced. If you see a landscape crew in your area, ask them if they are spraying herbicides, then cover your plants. Your HOA should inform you of herbicide applications as well. You have the right to protect your plants!