Heat Stress/Light Burn

Discussion in 'First Time Marijuana Growers' started by Shang99, Jan 13, 2010.

  1. #1 Shang99, Jan 13, 2010
    Last edited by a moderator: Jan 13, 2010
    Hey guys/gals I don't have a digital camera atm, or I would post a couple pictures. I have 3 Blue Mystic plants growing under a 400w HPS setup in an extra closet that I have. I just noticed tonight on the largest one that the edges of a couple of leaves are curling up a little. Would this be caused heat etc etc? Can anyone show me or confirm/deny this? I have the light about 15 inch from the top of the largest plant. Any thoughts would be highly appreciated. Thanks in advance.

    This is my first grow They are in FFOF with no nutes yet. Just watered them yesterday. They are also on a 24h light as of right now. 400w HPS like i said. Oh, also they are in three gallon buckets right now too.

    I also have a question about Topping. When should I actually start it? after how many nodes? Should the one i am actually cutting be a certain size before i cut it? What i mean is should i remove it as soon as i see it or should i wait for it to grow some then cut it? Hope that makes sense.
  2. Shang99,
    It sounds like heat stress if the topmost leaves on the tallest plants are curling up. How old are your plants? Have they always been under the 400 or is this a recent development? You say you haven't fed them any nutes yet so I'm gonna assume they're fairly young. The younger the plant, the less tolerant they are of excess heat and intense light.

    There are a number of rules of thumb about light distance, such as XX inches for a YY watt light, or placing the back of your hand at plant level for a minute and if your hand gets uncomfortably hot then your light is too close. These are good guidelines for older plants.

    Ultimately though, your plants will let you know if the light is too close. Try raising the light a few inches and see if the curling goes away. Good luck!
  3. Yeah, I had them under a couple of cfl's to start off with, but changed to the hps soon after. They are about 2 weeks old give or take a day. Also this is recent. I went to bed and it wasn't happening. When I checked them the next day it was happening. I guess like the edge/rim of the leaves started to curl up some. (not all the leaves just a couple)

    I did move the light up several inches when I first seen this. I just wanted to get some sort of hint that I was right or wrong in my assumption.

    Thanks for the help. It is much appreciated.
  4. if you gave me pictures id tell you if it was light burn or nute burn. Without it, it might as well be a friggen zinc deficiency, or a calcium deficiency. Or a magnesium deficiency. I guess you get to go search google since we got no pictures.

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