What length do the roots have to be coming out my 3inch rockwool cube before i can pop them in my nft tank 2 think i started on nft moved to soil,DWC but now i have enough room for all my equipment Gr8t so i,ll have staggerd crops in different systems pots etc but the question is as long as their roots through do i put em on top of spreader mat or w8 until they are a certain length as i,ve forgot all or any help well appreciated thanxs 420