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Thread: Brown spots and curling tips on multiple plants

  1. #11

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    I found this interesting, observe below... either way it appears either to be calcium/manganese/magnesium... which?... since calcium/magnesium can run hand in hand, and manganese def's appear with high PH levels.

    Deficiency Symptoms

    Because Mn is not translocated in the plant, deficiency symptoms appear first on younger leaves. The most common symptoms on most plants are interveinal chlorosis. Sometimes a series of brownish-black specks appear in the affected areas. In small grains, grayish areas appear near the base of younger leaves. Manganese deficiencies occur most often on soils with a high pH and/or naturally low Mn content. Conifers will exhibit a general yellowing of the current season's needles.

    Toxicity

    Manganese toxicity is a relatively common problem compared to other micronutrient toxicity. It normally is associated with soils of pH 5.5 or lower, but can occur whenever the soil pH is below 6.0. Symptoms include chlorosis and necrotic lesions on old leaves, dark-brown or red necrotic spots, accumulation of small particles of MnO2 in epidermal cells of leaves or stems, often referred to as "measles", drying leaf tips, and stunted roots. Sometimes the interveinal tissue will show "puckering" or raised areas in the leaves. Toxic symptoms can sometimes be alleviated by using Iron chelates applied to either the soil or preferably the foliage. Some acid-loving plants such as blueberries, cranberries, Christmas trees, azaleas, etc. may accumulate very high levels of Mn in their tissue due to the required low soil pH. However, these plants normally will tolerate much higher tissue Mn than other species.

    It appears your PH is stable but had to be skewed to be developing the symptoms. Best course of action is to "keep" your PH stable and apply "ALL" nutrients at modest amounts, your plants will then improve.

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  3. #12

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    Thanks for the reply guys.

    I wrote N/A for PH because I hadn't measured it at that time.

    Can I use calcium sulphate instead of dolomite lime to correct the calcium issue?

  4. #13

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    Quote Originally Posted by Woody J View Post
    Could I explain why this is NOT an Mg deficiency.
    Mg is essential to the photosynthesis process, without it, the plant cannot photosynthesise, so when a plant is deficient, the leaves pale due to the lack of photosynthesis, however, the veins stay dark.
    The leaves that are yellowing all have pale veins to go with the leaf matter.
    Where there is some striping, it is accompanied by necrotic patches, not yellowing.

    Therefore this cannot be an Mg def.

    Your ph is good, so the issue is down to environment or feed levels.
    The more I look at this, the more I think you need to increase the level of feed. This doesnt have to be 3 or 4ml per l, just go feed, water, feed, water for a week or 2 and see how they respond.
    A drop of superthrive or big bud or similar with each l of water and removing any leaves more than 50% damaged should see some improvements.
    W


    ^^ Boooooy.. if there was ever a post that hits the nail on the head it's that one.

    Biobizz at 0.5mls? Guaranteed there'll be a P def. Guaranteed. Then K. And mag at some point. Not necessarily in that order, either.

    Biobizz gets a lot of bad press for being low in mag, but these days it's not only is it low on mag, it's also WOEFULLY low on Phosphor. In fact it's low in everything but Nitrogen these days, it seems.

    Lately Biobizz have really cut corners on there nutes and I would no longer even recommend it for growing cannabis in good conscience.

    Trust in thine Tabba and switch to Plant Magic Oldtimer nutes. You'll see and end to both your mag and P defs. Oh, and you'll use WAY less of the nutrient itself avign you tons of cash.

    In other words, what I see in those pics is simply the effects of using Biobizz, and also way too little of it. I struggled like that for so long in my own groom until I stopped using Biobizz. I found that even at more than max doses (in hardwater) it still wasn't anywhere near enough P, K and mag for cannabis. Great for N, shite for much everything else nowadays.

    Oldtimer will take away your pain in 10 days.



    I am the light of this forum and I am its mean twisted soul.

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  6. #14

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    Quote Originally Posted by Tabbatha View Post

    Biobizz at 0.5mls? Guaranteed there'll be a P def. Guaranteed. Then K. And mag at some point. Not necessarily in that order, either...
    Well the plants are still in veg and I gave them 1.5ml / liter grow, and they are in all mix soil so even that was 0.5ml more nutes than recommended. + 0.5ml bloom and 0.5ml top max. I got slight nute burn now so I don't think they are getting to little feed at the moment.

    So I watered them a couple of days ago, and I gave them only 1ml grow because of the nute burn and 0,5ts calcium sulphate per plant and it seems to be helping.

    If you think this is a Phosphor problem, should I try and increase my PH to about 6.7 and give them only bloom nutes next watering?

    I can't afford new nutes right now, really broke at the moment. But I'll remember it when I start my next grow.

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    Quote Originally Posted by Dr666 View Post
    If you think this is a Phosphor problem, should I try and increase my PH to about 6.7 and give them only bloom nutes next watering?
    Actually, if you need to stick with what you have available for now, then that's not a bad idea as it will up the P in the soil for at least a week or so. Certainly won't do any critical harm. If it were me I'd throw in about.. say.. 4mls p/ltr of bloom.

    Good luck man.


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