how do u prevent heat stress with cfl close to the plant?

Discussion in 'First Time Marijuana Growers' started by dude1, May 12, 2010.

  1. i know with cfls, you're suppose to have your cfls as close as possible to the foilage, so i do that. but my leaves where the lights are at are curling upwards,i think its called cupping. theyre still green, small parts of the tips are burnt from nutes but the texture of the curled part feels try, which i think its from heat stress. so just i put cfls farther away? a little farther?

    - from the picture, does the leafs look normal? cus the tips are burnt on one of them and theyre curling upwards a little.

    Attached Files:

  2. the top of the plant , the highest point of the cola is about 87-90 degrees. the sides are about 85 degrees and the lowest part of the plant where u cant see is about 75 degrees. i have this laser thing where u can check the temp by pointing at it
  3. Not an expert, but I did just torch a bunch of plants because of heat/ I can tell you what NOT to do.

    Big problem for me was lack of air circulation. At least for my plants there seems to be a difference between 85 degrees with solid air flow, and stagnant hot air. Id try getting an exhaust fan in there to move air in and out of the grow environment...if you don't already.

    P.S....nice lookin plant, looks like your doin a pretty good job...
  4. hey dude what ventilation have you got set-up? get it replacing/bringing in more(cooler) air is a good start, also with cfl's its true to get em close as poss, but close as poss with out burning ur plants, so if needs be move em back a bit, but they dont really produce much heat to effect the plant so id say it could be your ventilation isnt good enough, in that its not replacing that hot air quick enough

    ps sorting your ventilation will bring those temps down also(which is much needed lol)
  5. nah i dont think mine setup brings in much NEW air. well heres how my setup is: the box setup is tall 4ft, and teh door, i cut it into 2 pieces, having the cut the be horizontal, so i only have the top part of the door open. i have 1 fan inside the box just circulating air, not sure if it bring in new air, but im sure it does a little. no exhaust cus i just leave the top part of the door open. but i do have a pc fan exhuast of at the top of the box but i dont turn it on since its so far away from the lights i dont think its strong enough to suck out air because the opening of the half door is big. but the lights are at about the 3ft mark and plant is 2 feet tall
  6. "As close as possible" means not too close. 90F is too hot.

    And you need actual air ventilation, meaning drawing fresh air in and exhausting stale air out, you can't just blow the same air around in an enclosed space.
  7. Setting up a small fan to blow across the top of the plant as well as the bottom, or plant facing, side of the bulb will reduce temps. It will also increase the brightness of your bulbs since CFL lumen output drops dramatically over 85 degrees. A CFL, or any other fluorescent for that matter, that is properly cooled should be between warm and hot to the touch but not burning.
  8. fan + trim the leafs

Share This Page