what are your light distances?

[Whippleschnitz]

I have a simple method of checking if my lights are too close. I stick my hand under the light at the same height of the canopy. If I can keep my hand under there without it getting too hot, it's fine. If my hand is getting hot or uncomfortable after a minute then the lights are too close and need to be raised.

If you try this I am pretty sure it will be an accuarate, if not scientific, method no matter what light or how you cool them. As always YMMV.

 

[Strictly_Kush]

I run a 1k air cooled light and I keep it about 10 inches from the tops... Without an air cooled hood it would have to be 2-3 feet from the tops...

 

[Fred]

I don't know how some of you guys are getting so close and liking it. I did it again after reading this and the same thing happens to me on some strains. I can keep my hand there all night. On the the glass even. Temp at the leaf is 84 and this is what I get.

same bud down lower. it's much fuller.

 

[Fred]

You can see better here. This strain shows it the most. Some are much harder to tell. I can only see the difference when trimming. Then I will notice the closest ones aren't quite as nice as the ones finishing 20" away from 1000w

Here is some more. Can see a lil better here. The bud on the left is a picture of the bud in my last post.

The bud on the right is here

They are on the same plant. The one that is running long is 10" away. The one to the right is 18" away.

 

[Kpezzy]

you have some fatties in there bro

 

[Xceptional]

Should be good with that. If it's air cooled you will surely be fine. With 1000w in a XXXL hood I have it 24" away with no problem. I let em' grow a couple of inches...at 20" I start to see heat stress so It move it to 24" and so on. I exhaust through mine but if I ran cool air intake on it there is no telling how close it could be. IMO any closer for a 1000w the light is wasted and footprint shrinks though. Been 24" for 10 years now and I like it...wit sum 3 footers under dare.....yuppers.

Your ambient temps are high, your airflow is too low or your strains are very temperamental to heat becasue i am running 2 XXXL 1K lights off of one 440CFM 6" fan in ambient temps are low 60's high 50's with a canopy temp of 79 in my room and i can get 5-6" away with no signs of heat issues.

 

[Xceptional]

I don't know how some of you guys are getting so close and liking it. I did it again after reading this and the same thing happens to me on some strains. I can keep my hand there all night. On the the glass even. Temp at the leaf is 84 and this is what I get.

same bud down lower. it's much fuller.

THIS IS STRAIN DEPENDENT! i have 2 genetics that do this my Chemo Cindy and My Lavender neither like high heat and will start shooting 3 finger leafs and then 1 fingers if i get them in the low 80s with no co2. now my other strains I've had friends run as high as high 80's with no co2 and they hold up just fine. pick strains that are strong and have been reported to do good in high heat if you can not get your heat in check.

 

[growgrow]

I keep my t5 like 5-6 inches....... does anyone else in here use a t5?

 

[sanvanalona]

You can see better here. This strain shows it the most. Some are much harder to tell. I can only see the difference when trimming. Then I will notice the closest ones aren't quite as nice as the ones finishing 20" away from 1000w

Here is some more. Can see a lil better here. The bud on the left is a picture of the bud in my last post.

The bud on the right is here

They are on the same plant. The one that is running long is 10" away. The one to the right is 18" away.

I believe it to be a sativa thing. It looks to me as if you are growing a sativa or sativa leaning strain, they seem to hate being close to the light no matter how cool it is, not sure why but that has been my experience.

 

[growgrow]

2 xxxl's w/ 1000w horts 6 invents w/ 8 in 750cfm vortex fan... i can get those babies like 6 inches away from the tops on my trainwreck... for some reason when I put my other xxxl close like that to my GROMAN (grapefruitxromulanxshaman) the tips of the water leaves will curl downward.. but when around 12 in or so... its good to go and happy .... let me know your thoughts

 

[Bearsfather]

My plants are within an inch or two of the light. 8 - 40 watt Fluorescents. I've burned a couple of leaves, and am right now a week or two away from harvest. I've grown from seed under fluors, 4 bulbs on top, 2 in front and back, horizontal. Everythings seems very good!

 

[robbiedublu]

I keep my t5 like 5-6 inches....... does anyone else in here use a t5?

T5s don't burn unless you have direct plant contact with the bulbs in my experience.

 

[subieslow]

I heard with 1,000's for example you want to be 20 inches up or more in flowering because overheated buds don't get as gooey. I think you can tell if only the center or tallest parts of your crops sunleafs yellow out during flowering signifcantly more than the rest.

 

[bongoboy]

With a 1000 watt HPS I gauge the distance by placing my hand under the light...if it burns my hand after holding it there, its too close. It's about 1.5 feet I'd say

 

[SoggyBob]

A good rule of thumb for HID'S is at least a foot. You want your top nugs rock hard. If you get closer than a foot, buds grow loose. The plant has to use extra water and energy to keep from burning. So if you use HID lighing your getting plenty of lumens to grow great buds, so be on the safe side and raise them up. Good airflow over the tops of the plants is also key to keeping your top buds cool. And this applies to cfl's as well. People think it makes a huge diffrence if the plant is right on top the light. I would keep the plants at least 2 inches away to avoide burning.
Good luck!