1. It rained so much this summer that half the vegetable crops damped off.
2. The shoots are beginning to damp off.
3. Don't give those plants too much water, they'll damp off.
4. Don't give those plants too much water; they will damp off.
5. Don't give those plants too much water of they'll damp off.
6. Don't give those flowers too much water, they will damp off.