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Thread: Could this possibly be Calcium deficiency???

  1. #1

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    Default Could this possibly be Calcium deficiency???

    Been growing a Greenhouse Seeds Big Bang Auto under a ViparSpectra V600 (400w) for 5 weeks to test it's performance, it's been lst'd and defoliated twice, and I flipped the Bloom switched on, on Sunday evening to begin the flowering cycle as it is now at the stage where I want it to be for flowering. However, within that first 18 hour cycle it suddenly developed brown spotting on all the fingers of one leaf, within the second 18 hour period it had spread to the leaf directly opposite it, but it has not worsened any, nor has it spread to any of the other leaves yet (fingers crossed it doesn't either) there is no yellowing at all either...

    I am doing an Hempy Bucket grow using Reverse Osmosis Water 0.00 p.p.m. - pH 6.6, I am using GHE 3 part series (Grow, Micro, Bloom), which I've used for over a decade and have done literally hundreds of Hempy's and never had any issues at all before.

    Apart from these two leaves the plant is lovely and green and very healthy with no other visible signs of the usual sorts of deficiencies associated with hydro grows. On weeks 3 & 4 it was fed on a solution of 1.7/1.8 ec at the end of week 4 I let it drain the reservoir to virtually empty approx 300ml left, as I normally do, to then reload it with the Flowering mix to an ec 1.4. This is the first time I have ever had this come up as an issue with this style of grow and the only variable that is different with this grow is the LED light, I have done them using both CFL's and HPS.
    I have grown Big Bang Autos many times so I know exactly how far I can go with the feed, because the parent Big Bangs are quite greedy feeders too...

    Is it possible that it could be some sort of heat problem?
    I have absolutely zero experience with LED's so have no idea what has caused this, because everything was fine until I flipped on the Bloom switch...

    Temps are steady at 27°c in the lower half of the grow tent (2'x2') and 28°c in the upper, I have a 14" oscillating fan and a 4" inline fan circulating air round so good air movement/ventilation and a powerful 5" inline fan extracting the heat from the upper area of the tent. The light is approx 53cm above the top of the plant as recommended not to shock the plant etc.
    No liquid has been spilt on these leaves, as feeding is done underneath and I have a specially adapted bottle with a funnel on so I can just pour it straight under the plants through the perlite, and the reservoir holds 2.7L of solution.

    Below are a few photo's of the two leaves that are affected by whatever it is???
    Any help/advice would be very much appreciated as I have never had anything like this before and certainly not with this method.









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  3. #2

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    It is a calcium deficiency, but I believe the increased intensity of your light is what caused the change. So it's kind of 50/50 whether you add calcium or raise your light up a bit.

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    Cheers Jingo, the simple answer is, I am at the upper reaches of my height limit for this test grow as the tent I'm using is only 1.6m, and my other grow room has photo periods in so I'm stuck at the moment, at a push I could maybe squeeze about another 4" but it would be very tight as I have two inline fans in the tent, I wonder if that would be enough though?

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    Quote Originally Posted by Steptoe View Post
    Cheers Jingo, the simple answer is, I am at the upper reaches of my height limit for this test grow as the tent I'm using is only 1.6m, and my other grow room has photo periods in so I'm stuck at the moment, at a push I could maybe squeeze about another 4" but it would be very tight as I have two inline fans in the tent, I wonder if that would be enough though?
    Well since you're in a hempy bucket with RO water and you just flipped the bloom switch you better give it some calmag. You'll probably be adding it in to every watering from here on out until you flush if you do that.


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  9. #5

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    Yea, looks like that's what I'll have to do, luckily it was only a test grow plant to see how the light performed to iron out any issues like this has I know nowt about LED's, and I'd rather have one little auto to take care of than a number of issues on larger plants, so it's probably a blessing in disguise really. The tent is what I usually veg in so it's not usually an issue, but it's a good learning curve for this new light, on veg mode these lights are superb!
    Thanks for the help mate it's very much appreciated!

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