Water deeply and less often, at the base of the plants, in the morning.
Leaves droop in the morning or evening, the soil is dry an inch down, or lower leaves turn crisp and brown. Hot, windy weather and sandy soil dry out fastest.
The soil stays soggy, leaves turn yellow, or plants droop even though the soil is wet. Let the top inch dry before watering again.
Above 90°F, check the soil again in the afternoon and water if it's dry. Drooping in afternoon heat is normal if the plant perks up by evening.
About half an inch of rain counts as a watering. The app skips watering when rain is likely.
Based on standard guidance from U.S. university extension services, including Cornell, the University of Minnesota and Oregon State.