Advanced Phosphorous Deficiency

Discussion in 'Growing Marijuana Indoors' started by PhenoMorph, Jul 12, 2019.

  1. #1 PhenoMorph, Jul 12, 2019
    Last edited: Jul 12, 2019
    So I wanted to show people what an advanced Phosphorous deficiency looks like, and remind people "don't get wasted when mixing your amendments"!

    I really shorted my plants this round, and killed my overall yield. I relied on bone meal, and not nearly enough of it because I brain farted, rather than a bat guano or mineralized phosphate source. I do have earthworm castings, compost and manure, but I also added extra N with blood and feather meal. With the high N, I had great growth until week 3 of flower, then they shit the bed when the demand for P rose and it was at a low ratio to the N and K.

    At first I chalked the red leaf stems and slight streaking to genetics, but with 4 different strains all behaving the exact same, and no cold temps, it lead me to conclude it was a deficiency.
    You can see the half dark green, half yellow lower leaves on some plants. Combined with red leaf stems and red streaking on the stalks.
    You can see the change in the look of the plants as it progresses.


    It started off with the plants going a deep (almost blue) green. Then red leaf stems and red streaking on the stalks.



    Shorlty after, the lower older leaves started showing a loss of green where the light hit them the strongest, and then dying off, then finally followed by a general pale yellow to the entire plant, which people often confuse with N deficiency.

    When you see that general pale yellowing/dull green, and all the other things I mentioned are apparent, your P deficiency has advanced severely and older fan leaves will start falling off quickly, eventually progressing to the bud leaves, then the tight-in sugar leaves if you can't slow it down, potentially opening up the door to bud mold.

    I managed to maintain mostly until the end with mild bottled organic nutes, only lost a very few buds to mold, but I had a significant loss of yield, and the bigger plants were affected the most. Less affected, smaller plants had much better aromas as P is important for terpenes and essential oils as well as weight and flower structure.

    My next mix has plenty of Gaia Bloom fertilizer and extra mineralized phosphate so I hope to not see this again.

    Good luck out there. I hope this helps someone spot a P deficiency early on.
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  2. Nice looking, you spent a lot of time in there.
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  3. Thanks man. Yeah she was a bit of work lol!
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  4. How can you tell if the red/purple stems are from deficiency or genetics

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  5. I was running 4 different strains, and they all showed signs at roughly the same time. And it went beyond the stems,there was red streaking on the stalks as well.
    It wasn't temperature either.

    I do realize it can be genetic. But once I saw signs like the blue/greening of the leaves it pretty much sealed the deal on my diagnosis.
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  6. Ok ,
    I'm running 6 different strains 3 have reddish stems on the fan leaves
    No signs of other issues so I'm just assuming that its genetics .

    Thanks .

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  7. No worries. Yeah I wouldn't fret too much almost all have some red in the stalks to a degree.

    Unless they go obviously deep red, or you notice them change, or suddenly deep green fan leaves, then keep an eye out, but a little red is pretty normal. This is a super healthy Afghani#1.

    Streaking on my Zombie Virus. Not so good

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