Leaves browning on one of my plants - help? (pics)

Discussion in 'Sick Plants and Problems' started by TheAzo, Sep 27, 2010.

  1. #1 TheAzo, Sep 27, 2010
    Last edited by a moderator: Sep 27, 2010
    The ends of some of the leaves on one of my plants are browning and have become very brittle.

    The leaves shown are the ones where the effect is most noticable, it is present only to a minor extent elsewhere. That plant is Nirvana's "Full Moon" - Sativa dominant. The other plants, including the other Full Moon I have are perfectly happy. This one was fine on thursday when I went away for the weekend. Soil grow.

    It is at start of week 6 of flowering.

    Have been growing 6 plants (2x each Venus Flytrap, Blue Mystic, Full Moon) in a closet under 400w HPS and 65w CFL (65w/200w equiv). Each plant is now drinking 3/4ths of a gal of water containing 2 tsp/gal of 15:30:15 fertilizer twice a week.

    PH of runoff after watering with plain water was 6.2

    It looks like it could be a phosphorus deficiency, but they should be getting plenty of that, shouldn't they?

    This is my second grow (first one had no issues like this), so i don't have much experience with plant problems. I was wondering if maybe the problem was from not loosening the pipecleaners I was using for LSTing earlier; the branch with the most symptoms had a significant groove where the pipecleaner i used to hold it down for LST was, but i don't know if that could produce this effect.

    Thanks in advance everyone!
     

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  2. "in a closet under 400w HPS and 65w CFL "

    Heat maybe?
     
  3. Hm, does that look like simple heat burn? It did get a little warmer than i'd like it to over the weekend...

    I'd love it if that were the case, because i could just ramp up my cooling and crank up the fans a bit...
     
  4. Maybe...IDK man, I've had heat problems and some of the ends of my leaves are yellow/brown on the ends like that.

    But they didn't/dont have the yellow spots in the middle of the leaves like some of you pics show...
     
  5. So you have about three to four weeks to go. Fan leaves yellowing out and dieing off in late flower is common, particularly with sativa strains.

    That's low. Not outrageously low, but low. The happy zone is 6.5 to 6.8. You are in magnesium lockout territory right now. pH is always the first thing to check, and when it is off, you should fix it.

    I would flush it with pH 7.0 water. Take pH readings of the runoff after the 1st gallon, then again after the second gallon. I bet the second reading is appreciably lower than the first reading. And the third reading (after pouring the third gallon) may be lower than the second. It can take some water running through before the salt deposits start to loosen up. After that you will be checking after each gallon poured, waiting for the runoff reading to turn upward. It will, eventually.

    If you decide to flush, you might as well aim for 6.8. If you aim for 6.5 you may find yourself flushing again in a week.

    Yes. Your bottled nutes should cover your plants nutritional requirements. When they fail to do so, it is usually because of low soil pH or an overabundance of one nute locking out another. For instance, potassium can get locked out by sodium or calcium. But I don't know of anything that specifically locks out phosphorous. It is normal to get some signs of phosphorous deficiency during flower, but it should not be extensive. So say the stickies.
     
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