I hope you don't think that I'm trying to be negative, but also consider that you stressed your plants from the very beginning. (Not sure if Weedhound knows the history.) Often when plants get stressed they slow down or even appear to come to a stop for a few days. Another thing to consider is that this sometimes happens with seeds. I wouldn't expect such a high percentage to be slow growing, but it is possible with seeds. If those were from scarified clones, they would be a foot tall and a foot wide or more by now. Notice how in one of your photos you see only one root? Perhaps being stressed during initial root production hindered the ability to make a huge healthy root mass, and the plant could only concentrate on the important tap root. If you scarify a clone you get dozens of roots instead of one. And to make matters worse, once a plant starts growing with poor root structure it will never have a chance to come close to growing properly.

The good news is that they are still alive and kicken. Just try to do everything correctly from now on and they will probably start taking off (perhaps slowly) sometime soon. I believe that a bunch of the problem was from the RW being too wet in the beginning, but now you know not to do that. And whatever changes yo make at this point, try to do it gradually or in stages. By all means see if you can get a mother or two going, so you don't have to go through this again. And listen to Weedhound, except for her biased views on SuperThrive due to a bad experience, she knows her shit. Good luck.
Opie Yutts Reviewed by Opie Yutts on . Can't figure out what's wrong... 3 weeks from bagseed, 1" rockwool cubes (pH buffered) and hydroton, 8" net pots in five gallon buckets with bottoms cut out. Flood & Drain / Ebb & Flow, 40 gallon reservoir. (res temp 71 F) RH = 40% Growroom temp = 75-78 F 250watt HPS light, with two 48" Floro tubes as side lighting, and a CFL for good measure. Rating: 5