Light Green Leaves & Yellowing Edges? Help!

Discussion in 'Marijuana Plant Problems' started by faded4life, Feb 6, 2011.

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    faded4life

    faded4life Member

    Noticed my plants leaves turning light green and then yellow....some pics I've seen on the internet indicates possible zinc def.....others tell me it may be a magnesium def.... any thoughts on what it may be? using black gold, 200w pro flourescent, 18/6 & watering at 6.5

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    Mother's Finest

    Mother's Finest Well-Known Member

    You may indeed have a bit of a Zinc deficiency, a fairly rare problem. There are actually a couple of pics circulating online of Zinc def labeled as Magnesium Deficiency.
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    faded4life

    faded4life Member

    thanks....that's what I was thinking.....just buried some galvanized (zinc) nails into soil.....slow absorbing so we'll see.....
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    robside

    robside Active Member

    if your ph'ing your water at 6.5 and have been since the start, thats way to low and your soil looks like it could use some perlite for air in the the soil. Ive read about "ph" on here and have had ph problems myself. . Ive heard 6.5, 6.8, 7 (which 7 in neutral) and it says 7 in the "Grow Bible" I even had the guy at the Hydro store tell me it should be 5.9 and "yes" he did know i was in soil NOT hydro, and he insisted it should be in the high 5's low 6's If your soil is ph balanced when you buy it, (I use FFOF) and you add water ph'ed at 7, or 6.9 it balances the soil to 6.5 or so which the plant likes. If you ph your water and or water nute mix at 6.5 ever time your going to over time bring that ph level 0.5 Down. Phing at 7, IS NOT TO HIGH nomatter what anyone tells you. You can always bring it down slowly, bringing it up I think is harder and more stressfull on the plant. My last grow i started phing my water at 6.5 to 6.6 and had problems from the start, looking back at my notes the ploblems started 9 days into vegging and continued throwout until i fixed the ph problem (bring it back up to 6.9, 7.0) harvest was still good and plentyfull but i hadthose same problem as your leaves (My pic looked exactly the same) It may NOW be a cal/mag def. BUT thats because of the ph being OFF BALANCED. FLUSH, FLUSH thats the first thing you should do, then try phing your water/nutes mix at 6.9. it cant' hurt!! remember that 7 is neutral and thats what the "Grow Bible" says. Also check your "run-off. Im on a new grow now, im in quart cups phing my water at 6.9 to 7.0 (out of the tap siding for 24 hours) and MY run-off is 6.2 to 6.3. Now if i was phing it like you have, at 6.5, id be in the low 5's which is NOT good for a soil grow. Well thats my two sence. If anyone can add to what i said PLEASE DO.
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    robside

    robside Active Member

    PS. if you are indeed having a ph problem no amout of "nails" or cal/mag will work, if anything it will make maters worse you most fix the ph problem first.. FLUSH then start back SLOWLY fixing the problem. Weed is very forgiving and will in most cases bounce back, thats why its called WEED, a weed will grow just about anywhere , in anything!!
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    faded4life

    faded4life Member

    thanks....makes sense....i'll check my runoff and go from there..... would imagine this applies to bloom stage as well?

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