CFL 105 watts... Distance from canopy up to 11 inches good growth?

curto

Active Member
Here's the link http://www.cannabis.info/UK/library/1258-cfl-light-distance

Now my past grows I've been putting the light 2-3 inches and burning the plant a lot in the process and I've had weak yields like under 20 grams a plant and this was using two 105 watt lights...

So now I'm thinking I should go around 5 inches away.. I'm already getting leaf curl because I had it 2-3 inches away.


What you guys think?

Again read this link, Ed said up to 30cm... which is about 11 inches
http://www.cannabis.info/UK/library/1258-cfl-light-distance
 

chrishydro

Well-Known Member
When they are in veg they reach for the light so keeping it up high is good as the plants are drawn to it. Once they start to flower I put my hand right above the top leaf if it bothers me I move it up until it just feels a little warm
 

HSA

Well-Known Member
Curto: listen to Chrishydro on the back of the hand rule. If it burns your hand it will fry your plants. I have two different brands of T-5 fixtures and they both recommend keeping them 6" to 1' above the tops of my plants but I usually keep them a about two to three inches off the tops with no trouble. Keep checking the heat of the air over your plants and if it feels hot raise them and if that doesn't do it you might look for another light source. I hope that helps. HSA
 

Guitar guy

Active Member
^ that information is incorrect.

You want the CFL's as close as you can without burning the plant. Use the technique the above poster stated. Hold your hand at the canopy and it the light is warm move it up.

The shorter a plant is, the more dense the bud will be
 

curto

Active Member
Well thanks, I do think 11 inches away is asking for a low yield.

I am thinking of keeping it about 4inches away... Since I don't have great ventilation either and I know heat can stunt growth...... I think I should be a little kinder to the plant(s) and they will reward me...

I'm trying to lay off nutrients for as long as I can.. Man do I suck with nutrients, well of course I don't have a PPM or PH meter so that's really why I suck. I'm getting a few brown spots on the edge of ONE leaf, I think I will add a dash of epsom salt next time I water... (the one with a few brown spots is about 3 weeks old, I have another one that's younger in the same soil with no spots)
 
Yes with cfls you deffinately want to keep them close but not enough to burn them. My 23 watts sometimes even touch the leaves its no biggie as long as it doesnt burn my buds!
 

yesum

Well-Known Member
I put my 55 watt fluorescent tubes around 1 inch away from the plants. I get a little leaf burn but if the buds are ok, who cares?

If you can get a small fan to blow across the top of canopy, that would really help too. I think with some fan air movement over the canopy, you could put that light within 2 inches of plant.
 

Ringsixty

Well-Known Member
The way I judge the distance is to use the back of my hand. if it is to hot for the back of my hand it's to hot for the plants.
I myself run 3 - 105 watt CFLs through out my whole grow. The light ends up about 5 inches away from the canopy.

Grow on:leaf:
 
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