Light distance

This site may earn a commission from merchant affiliate links, including eBay, Amazon, and others.

cjf2612

Tree man
Joined
Jan 21, 2007
Messages
223
Reaction score
45
My grow chest is 30 inches tall inside.With a 400w HPS can anyone tell me how close to the light I can allow my plants to grow without getting 'burnt'
 
hahahah now thats a funny question
around 2 feet away from you tip of a plant.
or just let your light run or an hour then put your hand under-it and were you will not fell the heat at all!! thats the hight
 
Thanks brouli, but I realy don't get it now. My grow space height is 30 inches so call me a twat if u wana but doesnt that mean I can only allow them to grow to about 6inches (12in per foot / 2ft gap leaves 6 inches ) in height to grow ?
 
you forgot to add the pot size :(

thats the thing man hps put a lot of heat if you put them lower you burn the leafs and then you f. i use CFL for veg stage cheaper much cheaper per month and ou can keep bul 2-3 inches above the plant
 
but how are you going to flower in 30 inch grow space unless you are growing LOWRYDER ??
 
besides the space 2ft is horrible for a 400w. with decent supplies it can be brought with in 6-12 inches.
my 400 is never more then 12 inches away.
 
ZMAN said:
besides the space 2ft is horrible for a 400w. with decent supplies it can be brought with in 6-12 inches.
my 400 is never more then 12 inches away.

I agree I allways have it within 18 " with a non vented hood.

Use the hand method, but as long as its not Hot on your hand its ok.
 
Def. need an inlined cooled light for that to work... then you can keep them as close as a couple inches from your plant.
 
Growdude said:
Use the hand method, but as long as its not Hot on your hand its ok.

If you can keep the back of your hand there for about a min that is what the plant is going to feel...if its really warm 95+ degrees move the light up. Thats about the best you can do. You have to keep your temps under control or its going to be hell.
 
DLtoker said:
Def. need an inlined cooled light for that to work... then you can keep them as close as a couple inches from your plant.

Even with a inline fan I think that would be way to close.
 
use co2 if your worried about temp.... you can grow up to 95 degrees that way. cheapest way to do it is to buy a paintball tank and remote on ebay, and spray it in. good luck
 
That space will not work for a 400. Someone just had a ? like that earlier, and we all thought about 4 ft. minimum, I think 6 but not 2.5 ft. Maybe a T5 flo
 
cjf2612 said:
My grow chest is 30 inches tall inside.With a 400w HPS can anyone tell me how close to the light I can allow my plants to grow without getting 'burnt'
Here is a chart for you to look at for a unvented hood.Hope this helps,and keep it GREEN:hubba:

HPS CHART.jpg
 
Great chart man. That is a good guide for beginners and pros. :) :)
 
With that small of a space you should check out CFL's or even better, some LED lights.
 
Anyone notice the date of the last post he left in this thread? lol.
 

Latest posts

Back
Top