Q. Does it harm plants to water with a over head sprinkler in the heat of the day?
A, No. However, overhead sprinkling results in water loss due to evaporation. If you do water by a sprinkler, it is best to use it in early morning to reduce evaporation. Add water slowly so it will soak deeply into the soil. Always water early enough in the day to allow foliage to dry out before night to reduce disease problems. Consider trickle irrigation and mulches to conserve water.