I heard about 4X4 area or 12 girls fo 1k. I've done 37 girls in soil but it was a bit much & yeild was low. But I'm still learning & made some mistakes. Also my recent batch was in a 4x4 tray Hydro with 20 girls. 15 would be a better number for that size. I'm not into cloning yet but what my boy tells me, he buys a mom plant & makes clones that way. One less headache for now until I get the growing down.