Sure they will but you'll find they're a lot more expensive to keep up than fluorescent. They also put out a lot more heat. The bulbs and ballasts don't last near as long.

I agree with taz for the most part,they can be more expensive depending on wattage and I would guess those are 400 watt lights. So yes they will cost more but you will get a lot more light for your money. Ovbiously heat will be a factor but 400 watts in hid is the same as 400 watts in flouresent, it just doesn't seem the same because floursent tubes are typically 4 feet long. As an electrician I can tell you that the ballasts in hid lights will go out as often as flourescent lights, it happens but not often. The hid lamps however do have a rated lifespan at which point their brightness will begin to diminish and I have read that it is actually hard on the ballast running them past their lifespan. Anyways, yes they will work for growing you just have to mindful of the heat they will produce and I would start with fresh lamps if possible. Depending on the cost of those I purchased my lights from htgsupply.com, they were cheap and have great shipping so you might want to look into that route as well. Good luck

Sorry for incorrect spelling,forgot to spell check