A few grows back I started soaking them in water until I see them pop a little at least a little. I started using the CANNA Rhizotonic this grow and it seems to speed things up a bit, I will add some cal/mag tomorrow and put some in a foliar spray with the  Rhizotonic and then they are going straight into the RDWC, I usually let them grow a couple of nodes before I do that but these will have roots long enough to reach the water in about 2 more days. Or I will do something stupid and kill them all.