1st of all. U dont feed them for a few weeks. Ur soil has enough nutrient in it to feed for a while. When the lower leaves start to turn color, hit em with a 1/4 strenght nute solution. Working you way up. Feed every other watering, or every3rd. Keep the light as close as possible, to prevent streching. Dont over water, and keep reading How-to on this site.. Good luck, smoke well