Leaves yellowing - pics and details inside

Discussion in 'Sick Plants and Problems' started by JesusGreen, Aug 2, 2011.

  1. #1 JesusGreen, Aug 2, 2011
    Last edited by a moderator: Aug 2, 2011
    Basic info about my grow:

    Grow box: PC case with one rear fan (exhaust rather than intake I believe) that is powered by an old phone charger. Other vents at the back are left open, however the power supply is still in the case (I used the connects from the power supply to hold the light up)

    Light: 105W (actual wattage) 2700K CFL

    Light cycle: 24/0

    Age of plant: Around 9 weeks now. Yes it is unbelievably small for this age. That's because it spent it's first 3 weeks on a garage window (behind frosted glass with barely any light at all, didn't even get its 2nd leaves in 3 weeks) then another 4 weeks under 20W, it's been under the new 105W for 2 weeks now and more than doubled in size.

    pH: Unknown, but I haven't encountered the yellowing after watering lately so I don't think this is a pH problem. Also last I checked the water I'm using is pH neutral anyway, so at worst pH is 7.

    Temperatures: Unknown too, but rather high. I didn't have any temperature problems with the fan working, however I repotted this plant into a bigger taller pot the other day, so it is only 2-3 inches from the 105W light, and with high temperatures already in the case I'm thinking this -might- be the problem.

    Other info: Repotted this plant 2 days ago in a larger pot. Closer to the light as I said before, but there could be some transplant stress. It was watered in. I also gave it a small dose of nutrients yesterday after I noticed the yellowing since I suspected N deficiency (as I haven't fed it in around a week and a half) - however yellowing got worse overnight so the nutrients didn't help, and possibly made it worse?

    Pictures:

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    This is how the plant looked last Thursday, there's a little old nute burn visible, and some heat stress, but both those problems were eliminated, and up until Monday (yesterday) no yellowing appeared except for the previous nute burn that.



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    These are from yesterday (Monday), you can see the lower leaves have started yellowing at the tips. The fan was off all day on Monday so I suspected either heat or N deficiency. I gave a very small dose of nutes in case it was that, and I fixed the fan.




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    Pictures taken just now. PS I put it on the window just now until further notice in case it's a suspected heat issue and leaving it in the case would make it worse. As you can tell, the yellowing got much worse.

    I'm not sure what the problem is. It could be heat since it's closer to the light now (unfortunately I have no extra room so the only thing I can do is move it to the side of the case by the vents and hope it's better there) - it could be that heat caused the initial yellowing, and my attempt to fix it with nutes resulted in nute burn causing the rest. It could be transplant stress. Possibly (but unlikely) pH.

    I really don't know. What do you guys think? Thanks :)

    Edit: PS I know the pictures are horrible quality. Best I could do with my phone and my camera's broken. Getting a new smartphone in a week or two so I'll take better pictures with that then.. but this is kind of urgent so I need help now :(
     
  2. I have over 200 watts of CFLs with Mylar and they're all 2 to 3 inches away with no fan and there is no heat stress so heat is not your problem it looks like nute burn.
     
  3. Are you sure? My box is pretty small and enclosed, my plant does feel warm to the touch, as does the soil, which would suggest to me the temps are pretty high. I'd guess 25-30C, so 77-86F.. but then again I just googled it and that seems to be the perfect temperature for weed.

    I have definitely seen heat stress with my plants but that was back when the back of the case was covered to avoid light escaping, so there was nearly 0 airflow and the temps were probably > 95F.

    Actually.. thinking about it I think you're right. Well okay then, do you think I should flush even though the soil is already still wet from when I fed yesterday and watered it in the day before?

    How much water should I use? I'm not sure what size the pot is since I knew nothing whatsoever about gardening or gardening tools before this grow, but Google suggests it's a 3 litre pot.

    Thanks :)
     
  4. It might be burned from the lights. Happened to me . I heard for best result is 1 feet away and put your hand over your plant. If you feel heat it's a little to close. btw no fan !?

    If this is inside .. a fan is a must! to prevent mold and so it's cool down there :cool:.
     
  5. I'm new to growing but I know for a fact 1 foot with CFLs is a really long way away to put your lights. Maybe with HID where the lights are a lot hotter and produce more footcandles so can be moved further away with less loss of light - but with CFLs, that's definitely a bit far - PC case grows would be impossible if that was the appropriate distance for CFLs, as a mid tower PC case is 22 inches tall, a 105W light is around 4 inches in height, then a foot is another 12. You'd be left with 6 inches.. including the plant pot..

    I have a fan, not sure why the above poster didn't use one, I agree that it's pretty important.

    I honestly, having checked a few times, think at most it's like 30*C, which is 86F, which is in Cannabis' ideal temperature range.

    So I'm thinking he was right about nute burn, my only question is how to go about flushing it - or if I even should when the medium is still moist.
     
  6. My temps haunt even touched 85 and I bought a small fan cuz I just induced 12/12
     
  7. Anyone have any answers yet on what I should actually do to treat this?
     

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