GMSgrowsanswered grow question 4 years ago I always started my seeds right in the rockwool cubes pointy end up and place right into the netpots as they germinate. Start your system up about 4 days after the girls appear with 250 ppm. My system was rdwc and the water line to the buckets entered at the top beside the net pots so my clay was alway getting pretty heavy flow of water from the time the roots broke through the rockwool.