a cry for help ...

grow bros !!, a bit behind here in southern hemisphere outdoor grow and now i have some baby problems... all in the same mix 1/3 perlite, 1/3 coco-coir, 1/3 my own compost grown many times successfully and not all the plants are showing the symptoms but they are all in the same soil mix. All my ATA TUNDRA are showing this more severely than other varities (sleestack x skunk and Hawaiian x skunk) less so .... i cant find any trace of bugs or anything .. totally stumped ... ??

used neem oil and potassium soap once for thrips
plants are totally outdoors temps between 10 and 30 c or 50 - 85 f
any feedback would be great, i was thinking something to do with the neem or maybe boron deficiency ? but in such young plants ? .. 3 weeks from seed .. looks burnt or eaten or something ....? anyway cheers peoples

cheers vostok .. and yes i was thinking the coir too so nice to hear that repeated ...

could it be related to salt in the coir ? i read that some cheap coir products have high salt content, i flushed the coir several times but maybe not good enough - i will flush like a madman

Not eaten, you can see that the leaf tips are still there so defiantly not chewed off. Looks like advanced mag def, but like you said, not at 3 weeks. I do know one thing, 50F is too low, especially for such young plants. 60-65F at the least. Temps play a major part in P uptake. Not saying it a P def. I've never had to deal with a problem like this just throwing a couple of things out there. Good luck I hope you get it straight.

hey thanks polo yeah we have had some extra cool nights here kinda out of the norm down to 50f the other week, they are in a poly tunnel to keep warm at night, but maybe still too cool. this is the first year i have done the whole thing outdoors, usually i start under cfl, harden off outdoors for a few weeks then into the bush plot. thanks for the input, appreciate it all. cheers.