I drain the water from the saucers, except on hot days, i.e. over 80Ã‚Âº F. On hot days, the water evaporates within a couple of hours, and I feel that it increases the humidity around the plants. My container-grown tomatoes sit on the south side of my house, on white gravel. It gets hot out there, and dry. When it's very
hot out, I hose down the gravel a couple of times during the day.