hps question

I just ordered a 400 watt hps from htg supply I wanted to go bigger but I'm worried about fire So I figured I would see how this goes.How many plants can I light with a 400?

some people say only like 5, but I have several books that say a 400w HPS can light up a 25 square foot room nicely, so I'm thinking like 15? 20 maybe 25 if you go sog or somthing. but yea. I'd say 8 is a safe number.

Thanks that should do for a start.

i am a first time grower, so my knowledge should not be heeded as truth. i have always known to go by the rule of 100 watts per plant. i have 6 plants right now and 1200 watts of hps. you can't "over-light" your plants unless you burn them with heat from the lights. the more light you give. the better buds they produce. i say go with 4-5 with a 400 watt lamp. watch the video "I Grow Chronic!" on youtube. very informative. will answer alot of questions you have

yea I grow cronic was a good series. I made a mistake It will light a 16 square foot room, 25 if you have a light mover. I have a 400W HPS and a 17 square foot room and I had 8 plants and they did fine.
I knew someone who had a 250w HPS and a 150W MH and grew 12 decent plants... I think he used alittle magic too though...

It all depends on how big you want your plants, how much you feed them, how close you can get the lights to the plants, how big the footprint of your shade is, and lots of other factors.
Basic rule of thumb, which i know lots of people think is overkill, is
50w/ square foot. I use a 1000whps which covers about 4'x5' total of 20 square feet 1000w/20sq'=50w/sq'
Doing the math, it doesnt seem right....for a 400w anyways...only 8sq'
If you do a search on this forum, you will find a couple charts which get into lumens per distance, and other interesting stuff.

good luck