I like to keep my mothers short and squat, Train out four main branches that I trim the plant back to and let it regrow from there. I knew a guy who would keep his bonsai mothers in 4" pots. Things worked really well, root pruning them every six months he was able to keep mothers for a very long time.
Smart pots and peat-lite for me. They buffer well and hold a decent amount of moisture etc. The plants really love it and I've only had one problem. I've been constantly feeding at 50 PPM N since I put them in the soil. I even up the same res to 100-150 PPM N and my mothers just love it. This is with peters 16 - 4 - 17 Hydro FEed
My soil EC hangs around 1.5 with this, with a pH of 6.5. Works reallly well.
Well, FWIW, now that I've confirmed my clones have rooted.....
I've transplanted my 4 mothers into FFOF in which I mixed some of Caps Nute & Root, some biochar and some MET52 Granular. I know that its kinda redundant to use the MET with CAPS, but I got a huge sample for free (actually the biochar was a free sample too) so why not?
I also root pruned each of the mothers. Might kill them, or they might be killer! We'll see....how can we learn if we don't try?
For those of you using RO, do you use any Cal / Mag when you water in soil? I'm thinking my OG's are going to need it.