When to transfer rockwool to hydro system?

[thamnophis]

How big should the plant be before I transfer it to the hydro system? I have some whose roots are just beginning to poke through the outside of the rockwool cube. The plants are just beginning to show their "real" leaves.

Joe

[Makee]

I think you should move them now because there ain't no more space for the roots. I moved my plants to hydro when they were in same condition and they are growing ok