How old are your plants?? if there seeldings then you can get away with low wattage say 2 per plant for a week wont hurt, breaks your seedlings in for the 400watter, when times where bad for me (didnt have the full set up) i had to go with 2 20 watt cfls for a week on 1 plant and it was fine, Make sure you got plenty of reflection to help. Just remeber 6500k daylight for veg, and warm white 2700k flower, you can tell the difference warm white give off a redishy colour, daylight/softwhite is a bright white more bluey. This 400watter what is it hps? (( i was the first one to give you the answer o yer))