Potassium deficiency or something else?

I have some Afghan Kush growing in 50% soil 50% coco which have started to show the following symptoms

The plant has been grown under a 400w hps with a 12/12 light schedule from seed going on the fourth week now.
I've been feeding the plants a basic npk nutrient and even some bloom nutes, but since i think i mightve miscalculated how much these plants need in the coco soil, as ive only grown in prenuted soil before. What does it look like?

I might add that it only just started showing these symptoms, so it seems quite rapid.

Looks like a potassiu deficiency or pH issue (could be both, related).

Like infdjedi said it could on both or one or the other. I had a potassium problem and used fox farm beastie bloomz and it fixed it.

Thanks for the replies!

I would think more likely PH related........
I don't know for sure, but it sounds like you may be fighting yourself, as coco likes hydro PH, and you have it mixed with soil.
I'm not sure what that is going to do.

Alright, the boys at my headshop recommended it, so im going to have to experiment a little and if all fails its back to soil

It's a ph lockout. If you haven't been phing your water before feeding your done. Especially in coco. Potas locks out below 6. With 50/50 cut the coco is absorbing and holding the ca, and potas.

Weebay said:

12/12 light schedule from seed

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How come everyone missed this part ?


Poor plant doesn't know what it supposed to do...no wonder you have nute problems.

I'm surprised it's not flowering or herming.

this guy gets killer results with 12/12 from seed. https://www.rollitup.org/indoor-growing/416589-12-12-seed-thread.html

its actually not that uncommon. i think you might be a little more confused than his plant.

ogreb said:

How come everyone missed this part ?


Poor plant doesn't know what it supposed to do...no wonder you have nute problems.

I'm surprised it's not flowering or herming.

Click to expand...

What does 12/12 from seed have to do with P and PH?
Lots of people grow 12/12 from seed.

MikeHancho85 said:

this guy gets killer results with 12/12 from seed. https://www.rollitup.org/indoor-growing/416589-12-12-seed-thread.html

its actually not that uncommon. i think you might be a little more confused than his plant.

Click to expand...

Wow! I've never heard of that! Gonna have to check that out. Thanks for the link hancho.