this is quoted from the Garden Knowm

water them thoroughly and get some oversized trays for your containers that can hold run off.... water your pplants until the trays are filled to the top...

then reduce yur lighting to 10 on and 14 hours off.. less heat will make your final watering last LONGER..

A good thorough watering of 1 gallon of water into a 5 gallon container, in a room with a temperature of 70-75 degrees, should last a plant that is in the final week of its flowering.. at least 7-10 days.. AT LEAST!