I have a 20"deep, 37"long, 27"high grow box which will hold about 3-5 plants, the fluro's i have now i don't think are enough so i want 2 get an HPS light, but idk what size wattage i should get? any suggestions, Heres My First GROW for which im going 2 use the HPS
if you grow area is less than three feet tall then I wouldn't recommend HID lighting (hps or Mh bulbs) because they generally need to be hung three feet away from the plant. Fluros may be the way to go since you can hang them inchea from the top of the plant, and you have a shortened grow area
Not true..a 250w hid light can be as close as 8-10 inches. The only hid's that need to be 3 feet away are 1000+ watters. But i would use fluro's probably, 3 feet is a very small space. The pot is going to be atleast like 9-10 inches tall, plus the hid would need to be around 10-12 inches away if your using a 250w, so that would only allow your plants to grow a little over a foot. You might be able to pull it off with fluro's but they still wouldn't be able to get very tall, so yield is going to be very small.
i have a 250W hps and i keep it 8 inches about the top cola (im flowering). i have very short bushy plants and my growroom is 4 feet high, and im still almost out of room. if you dont have a good height clearance, definately do flouro. im doing cfl's too.