hmm i was at a grow shop today and they were also saying good tings about that coco shit. She said thats all they use in europe and down under. but she wasn't pushy at all. but what she did say is that the biggest difference between it and soil is that you NEED to use 1 more fert. a Mg and calcium fert. i'm not saying tahts what you got but maybe read about it.

as i read your post i was thinking heat stress and i would say you have too much of a change. 20 is too low and 30 is a little too high. I keep mine at 79 F which is 26. Maybe try to smooth that out.

is your light to hot for them. What kind is it
also, the shit she had was a compressed brick (like a big peat pellet) and it was 100% coco so i dont know what you got. she said it didn't need perlite (which is bad for the environment) she was pushing (not really, just always telling me about) the green options, which I liked
harris7 Reviewed by harris7 on . Question With Coco Coir....... This is the second time I have tried to grow in Coco. the first time I didn't have great results so I scraped that and went with Promix I had good results. Now I tried Coco again grotek Coco mixed. The grow shop keeps pushing this stuff on me instead of ProMix. I used it again and I have added dolomite Lime as a buffer tested the coco it was at 7ph I put my seeds in and after 1 to 2 weeks from sprout. The first set of leaves has already gone yellow and they look stunted as shit. ill Rating: 5