As soon as the seedling emerges from the medium you need light.
Rockwool isn't the easiest germ medium. Rapidrooters are a good pre-fab 'plug' product that is compatble with soil or hydro, or a fine unferted 'seedling starting mix' soil in dixie cups is another good option.
stinkyattic Reviewed by stinkyattic on . Rockwool and T5 Germination If someone used rockwool to germinate, would they put the rockwool directly under the T5's after putting the seed in? Mandala seeds suggest that you can use rockwool but they don't say if they put it under the lights then or after it sprouts. Any help? Rating: 5