Help with burnt spots and leaf droop

Hey all, I'm having issues with a plant I'm currently growing. I'd appreciate any input.









The strain is unknown (thread on its life so far can be found here - https://www.icmag.com/ic/showthread.php?t=361949 ) although I'm pretty certain it's Afghan hash plant X world of seeds ak as the ahp suffered the same yellowing despite being in a decent soil that my other plants are loving.
Soil composition is Coco coir, compost and ewc. It's been fed once with 0.5ml each of bionova veganics grow and bloom with a pinch of epsom salts in a litre of water. It's currently on the last days of its first week in flower.

I'm wondering if the cupping is due to temps as I currently can't get the flower space under 30c even with the extraction on full. But the drooping leaves and spotting I'm lost on. Anyone got any ideas?

The parched spots on the leaves indicate that the soil is hot or the EC is way too high. Or the soil is too dry.

The pale lower leaves look like nitrogen lockout. Nitrogen is a mobile nutrient and affects the lower leaves first and moves up the plant. Same for phosphorus, potassium and magnesium. However the pattern of damage of the leaf suggests nitrogen lockout. Potassium and magnesium deficiency affect the edges of the leaf first, and potassium's leaf damage usually curls upward.

It's hard to tell from the photos, however the high temperatures may also dry the plant and soil out faster than usual.

I would give them 0.4 EC of bloom food (low nitrogen, higher phosphurus and potassium), check the EC of the run-off, and from then bottom water every day with plain tapwater. Water and nutrients should also be acclimated by putting it in the grow room for at least an our, a day is better. This prevents a temperature shock, and allows at least chloride to evaporate.

Bottom watering keeps the nutrients in the soil, while slowly reducing the nutrient concentration as the plant takes up more nutrients. And doesn't let the drying soil increase the nutrient concentration to toxic levels. It also allows the plant to be watered by evaporation, which is important with higher temperatures.

Must declare I 'm not a coco grower but ... I would say the spotting is the result of spillage of something (nutes?) on the leaves. Calcium def might do this but those marks are irregular, unlike Ca def.


Cannabis won't mind 30C at all! But I think your plant needs a drink. It looks like it's been over fed ... but I think if you give it more water the overfed look will go away ... and your plant will grow some more.


(Tanzanian Magic posted at same time as I was writing! I see underfed on bottom leaves but that's not where the action currently is. Those leaves will drop soon and that's ok. The upper part of your plant shows overfed or underwatered. I think T A is saying sit a saucer of water under your pot. just a saucer, no deeper!)

JockBudman said:

Hey all, I'm having issues with a plant I'm currently growing. I'd appreciate any input.

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The strain is unknown (thread on its life so far can be found here - https://www.icmag.com/ic/showthread.php?t=361949 ) although I'm pretty certain it's Afghan hash plant X world of seeds ak as the ahp suffered the same yellowing despite being in a decent soil that my other plants are loving.
Soil composition is Coco coir, compost and ewc. It's been fed once with 0.5ml each of bionova veganics grow and bloom with a pinch of epsom salts in a litre of water. It's currently on the last days of its first week in flower.

I'm wondering if the cupping is due to temps as I currently can't get the flower space under 30c even with the extraction on full. But the drooping leaves and spotting I'm lost on. Anyone got any ideas?

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It’s hungry. You fed one time at 0.5ml but the use rate for that product is 12ml veg and 5ml bloom.

You’re making it worse by supplying Epsom. Magnesium promotes nitrogen use. You added Epsom but no nitrogen to compensate (or any other nutes if you’re only using 0.5ml) It’s pulling nitrogen from lower leaves to make use of the magnesium you gave it. My opinion.

Thanks all for the advice, I've been lurking the last few days and not posting but I have taken action on this.

Seeing as the consensus was for nitrogen issues and bearing in mind the mother of this cross was very very hungry, I have fed with 1ml of bloom solution after a good watering to prevent nutrient shock. 1ml brought my ec up to just under 0.4 as TanzanianMagic prescribed.
I will also be reconfiguring my space as soon as I have time, to get saucers under all the plants and start bottom watering and feeding.

Regarding my soil, it isn't pure coco, it's a peat free mix I make myself and so far it has served all my other plants very well. So well in fact that I have a very hungry clone in it that has always yellowed early in flower still dark green three weeks into flower. Very very light colour change to lower leaves but believe me when I say this thing drank nutes down constantly the first few runs and it was hard not to lose all the leaves.

The philosophy I've adopted for feeding is the one taken from Mandala Mike on here - use a good organic soil and feed as little as possible. I've had nutrient lockout issues in the past caused by overfeeding (hence why I was and still am feeding so low a dose.) It is working for all the others I've got on the go but this Afghan clearly needs a lot more. I'll bear it in mind when I go for a full seed run of the line.

Again, thanks all for the advice. I'll try to update once I've seen what she thinks of this feeding and hopefully we can get her to harvest without further issues.