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Thread: Magnesium deficiency?

  1. #1

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    Default Magnesium deficiency?

    Hello friends,

    The lower fan leaves on my 32-day old Stress Killer are starting to show brown/copper spots. So far I see those only on the 1st and 2nd node fan leaves. My other plants are fine, but they're also different strains.

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    Reading the stickies, I would guess it might be a Mg deficiency. I'm not using Cal-Mag and am using rain water to water my plants, so that would make sense I guess. The plant is in a 4gal grow bag filled with Biobizz light-mix; am feeding it with Fish-Mix, Bio-Bloom and Top-Max, all at 1/2 strength (which I hear is sufficient for autos).

    Does that seem about right? Thanks!

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  3. #2

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    Default

    I think I vote more for calcium than magnesium, magnesium generally causes a yellowing out of the leaves starting between the veins, whereas calcium gives you kind of rust spots in general. It would be okay to introduce some quality calcium magnesium supplement into your feeding, but most of them I've seen have nitrogen and you're already about as green as you want to be so you want to reduce your nitrogen source if you're going to go add calcium and magnesium.



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  5. #3

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    Great, thanks a lot for the advice! I'll get myself some Cal-Mag ASAP.

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  7. #4

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    Rain water has no cal or mg in it like tap water does, unfortunately tap water has chlorine and chloramine chlorine will evaporate out but an excess of chloramine does not and will build up in the plant causing lockout.
    So much to learn, so little time to learn it

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