MASTER GARDENER WITH THE ONLY HORTICULTURAL SOUND REASON TO IRRIGATE IN THE MORNING.
powdery mildew (10 different types)
phytophthora brown rot
phytophthora root and crown rot
armillaria root rot
Just to name A FEW of the diseases that grow and attact plant when they remain cold and wet during the night.
U.S. Dept of Ag, U.S. Dept of Forestry, every state university extension and every licensed or certified horticultural expert in the U.S. and Canada all agree that irrigation should be done in early MORNING so plants are not allowed to remain wet any longer then necessary.
There is not one valid hort. reason to irrigate at night.
IRRIGATE IN THE MORNING! PERIOD! END OF DEBATE!
Garden Dok. BS, MS, MG. Univ of Calif coop Extension