1 - Don't grow them in rocks.
2 - If the seedlings have roots coming out of the jiffy pucks plant them into soil right away because once they are planted into soil they will start to grow alot faster once their root system gets big enough.
there all goin into 4 inch rockwool cubes in a week when they come, then going into 1.3 gal pots with hydroton then into the ebb and flow...
put the rocks there to stop the roots drying out, cause they all poping through an not growing an drying.