how long to leave grow light on plants
Cycle the grow lights on and off appropriately. You cannot maximize plant growth by simply leaving the grow lights on 24 hours each day. In fact, this is a good way to stress and kill your houseplants. Instead, aim to leave grow lights on continuously for about 14 to 16 hours each day, which simulates spring sunlight. A good way to ensure that the grow lights are cycled on and off each day is to wire them to a timer. You can purchase a light timer at most home improvement stores.