The rule of thumb for lighting is 50 watts per square foot of growing space (floor space), it can be a little less though. A 1000w lamp will cover an area of 5 feet x 5 feet (maximum). An area of 4 x 4 is good. The amount of plants depends on how big you want to grow them. You can grow them bigger than 1 foot under a 1000w lamp. The plants double or even triple in size by the time they've finished flowering, so if you flower them at 2 feet tall, they'll be about 4 - 5 feet at maturity. This depends on the strain though. Your electricity bill will increase a fair bit. It won't be too bad if you're only using the 1000w lamp for flowering because you'll only be running it for 12 hours a day. If you use it for vegetative growth where it will be running for at least 18 hours a day then your electricity bill will increase significantly. It's best to veg under fluorescent lights and just use the HPS for flowering.

good luck.
GTC21 Reviewed by GTC21 on . 1000w hps??? guys how many plants can a 1000w hps light setup cover?,how many plants could I flower at one time under this setup?,also whats the average kilo watts these lights burn a month on a 12/12 cycle?......would my light bill increase much?, o'h ya the question about how many plants could flower under the 1000w set up,I would start flower when the plants hit a foot (12)inch's or so...........can't seem to find any facts on this issue??? thanks. Rating: 5