How close can plants be to 1K watt light?
- Thread starter Mongo100
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BWC BayArea
Member of the Month: 3rd Place Winner
1st off welcome to our online community. I hope u find all the information u seek. There is a plethora of valuable info in these threads. Please feel free to use the search feature in the mid upper right portion of the screen to peruse our forums and threads. Now to ur question. Light 10", pot 8"-16" leaves a minimum of 30". Which means u should start LSTing ur plants or flowering them short unless u already have a strain bred for short crops. I'm assuming ur using an HPS lamp.
With ur set up that's a tough one because as your plants grow taller Ur gonna want to raise your light with them. I started hanging a 2' string from my hood (600W HPS). Once the canopy starts to pass the tip of the string I know to be aware of the possibility of light burn. If they're not affected I don't bother them. Eventually I raise the light until they stop stretching in flower. Then I let them get used to it and sometimes lower the light for more usable lumens. For a 1000W aircooled, Jorge Cervantes recommends leaving at least 24". Hope this helps. Its kinda hard to give specific answers with only some of the required info. Please read this How to Ask for Grow Support to help us better help u.
With ur set up that's a tough one because as your plants grow taller Ur gonna want to raise your light with them. I started hanging a 2' string from my hood (600W HPS). Once the canopy starts to pass the tip of the string I know to be aware of the possibility of light burn. If they're not affected I don't bother them. Eventually I raise the light until they stop stretching in flower. Then I let them get used to it and sometimes lower the light for more usable lumens. For a 1000W aircooled, Jorge Cervantes recommends leaving at least 24". Hope this helps. Its kinda hard to give specific answers with only some of the required info. Please read this How to Ask for Grow Support to help us better help u.
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I have read that the plants can be very close to a HID HPS light as long as you are air cooling it and you can leave your hand underneath it for several seconds? For the next year though I am going to have to deal with a small (40 inch) tall grow box. I will post pics tomorrow. How much vertical growth happens once in flower?? Can I start to flower the plants at 15 inches?? 
BWC BayArea
Member of the Month: 3rd Place Winner
Well if u read it and believe it give it a try. I just hope the person that wrote it is credible. Just know that there is a reasonable margin for error having never done so. There are a few reasons I don't use 1000W lamps, the answer to this question is one of them.Might I suggest searching the threads, plenty of good info. This question has been asked b4, I'm sure of it. U can begin flowering whenever ur plant reaches sexual maturity (showing preflowers indicating gender). From seed it takes longer that clones. Good luck.
retired again dude
New Member
I keep the 1000watt light I use 1 to 1.5 feet from the closes top bud. I cool the room with my central air in the house. My tempture stays at 75 to 80 degrees no vented ficture. I also use a fan blowing over the air between the lamp and plants.
Racefan
Well-Known Member
I get my 1k about 4 inches away but I'm using a light rail and a air cooled reflector too.My grow box is only 48 inches tall my light takes out around 10 inches. I have a 449cfm fan sucking out heat and light fixture is cool to touch. How close can my plants get to the light??
Cannabinoid
New Member
I prefer to run rooms at 81-84 degrees to speed up photosynthesis, however you must add more CO2 enrichment to compensate. 18-24" is what I am aiming for (18" early on in the cycle, and 24" later. Cooling is a huge factor in the distance you can place your lights, especially 1000w.
retired again dude
New Member
I keep my lamp 1k 1 foot from the top of the plants/buds You may get it a little closed because of your ac/strong exhaust fan......but I would still keep them a foot from the bulb or you'll end end up burning them not because of the heat but the light intensity at that close elevated level.
