Can CFL's Burn Plants?

i recently started my first grow starting wit 6 35 watt 6500k daylights everything was going brilliant til i was watching you tube and it seemed like everyone was telling everyone else to move the lights closer to the plants until they are almost touching "as the give off very little heat" so i did then goes out this morn and one of my plants is completely brown n crispy K.I.A and d rest wit some badly burned leaves by d way my plants are about 2 weeks old. why do alot of ppl say 2 do this when iv obviously found out d hard way dat it is clearly not true and they were 6500k i really wudn like to see wot damage the 2700k wud do at that range.

CFLs have very little penetration, and need to be within a few inches (or closer) of the plants to be effective. However, they will burn the plant if they actually touch the bulbs.

proper ventilation is key. You should be able to put them an inch or two below the light. But you should have a fan on them to push the heat away too

I use CFLs and I keep them about 4-6 inches above my plants, and they work wonderfully. I have not begun to flower yet but for veg they have grown into little bushes (10-15 inches high with multiple tops I have been pinching the branches and they are looking lush!) in about a week and a half to two weeks. From 4 inch clones! My grow box also has a wall of full spectrum FL bulbs (35 watts x 6 bulbs) so maybe that has something to do with it as well.

If you have no ventilation then yes they can burn your plant if they touch the bulb... with a small fan blowing on the bulb you can easily get the plant inside the 1 inch mark of the plant itself with no issues.

"Almost touching" is not exactly how I would advise someone, it's not very specific. CFL's can easily burn leaves, and the bigger ones can get hot as fuck. As mentioned already, a fan blowing on the lights will cool them off quite a bit, making it possible to get real close.

Inside of 2", preferably closer to 1" -- that's where you need to be.

Sorry u burned ur plants. They should still grow, right?

cfls can burn if too close to young plants and deff if they touch. a fan blowing on the lights will cool them. even if theyr not hot enough to burn you prolonged exposure to plants will end in what you just experienced. sorry for stating the obvious or what has been said already but im speaking from exp. good luck with the rest of your plants

thanks 4 the advice it makes alot of sense i am running a couple of 100mm pc fans though i obviously made the box b4 i started d grow so there up above d lights and plants like bro montana in the couple of weeks they have grown like almost 100 percent foliage and 0 percent stem its pretty cool very interested 2 see how they do in the coming months. thanks again 4 d tips on the way out now to make some sort of platform so everythings level wit d fans

I got a plant that's 12 days old...I just put a dome light and 2 23w 6500k bulbs on her...one bulb was prolly an inch away...she seemed to jump right up and like the light...I left it overnight and i have a little brown at the end of the leaves....I am thinking b/c I pretty much completely covered her with the dome light, and it might not have had enough air flow, and got too hot inside

Sorry for your loss. I just recently had 6 seedlings starting under 2 42w cfls, with fans, and it got pretty ugly. In denial I tried to continue growing, saying to myself i over watered and shit. No lights were too close and too hot. One made it though. It was only bagseed thank God but, u kinda have to find your own way. I personally think anything above 23w-26w range should be paid carefull attention to. And start off with say 3 inches, move close if your comfortable with it, and check it from time to time (1/2hr-1hr).

the best growth ive seen with cfls, was when i had 5 23w cfls in a star (bulbs out) 6 inches above the plants.

all the lights intersecting and boosting eachother nicely. (get too close with the lights and they arent boosting eachother up, though with a single light it doesnt matter)

reflector of course above the "star"

could do the same with 3 bulbs too, or more than 5.

Yeah I think 4-6 inches is more like it in my exp. The thing is if you are using a fan like most of us it will help keep them cooler but it also makes the plants move around, and at 1-2 inch away you are gonna get caught up in the cfl at one point or another. Another thing to maybe keep in mind is alot of cfl users just have the lights hanging by the electrical cord (if not anchored), thus also making them move around. I check my plants a lot, but with close range its still to difficult to keep plants from getting burned at that range. If you are fine with adjusting the lights once or twice a day then go for as close as you can. But remember that these plants can sometimes hit a growth spurt when you least expect it and jump a couple inches almost in a day. I think anything under 3 inches is more trouble and risk than what its worth.

I used to put mine within 2 inches but the plants grow so fast that I decided to put mine at 4 inches. Basically, if you have them at 2 inches you need to make sure you're checking them 1-2 times a day. At 4 inches you can simply check them once a day without having to worry about cooking any leaves.

Yea they can def burn if touching....

delighed to report the 3 guys that didn burn as badly as d fourth one are recovering well and doing just as if not better wit d lights at bout 4 inches away i also took d advice about havin my fan blowing directly onto the bulbs which id say is a big help. i know it was a simple logical solution which i really shud of realised myself but i just paniced that morning and logged straight on here. thanks 4 d feedback everyone. its my first grow and wud be lost without a site like this. Big thanks 2 whoever keeps the site running as good as it does. thanks

easyrider23 said:

I used to put mine within 2 inches but the plants grow so fast that I decided to put mine at 4 inches.

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Exactly when did "grow so fast" become so undesirable?