I start seeds in a wet paper towel until I get a 1" -1 1/2" tap root.. I put the seed (pointy side down) or sprounted seedling (tap root down) into a rockwool cube I've pH'd in 5.0 water for 24-48 hrs. I dont put the baby far down in the cube, just a 1/4 " or less. I put the cube in WELL RINSED hydroton and make sure the top of the cube is even, or a little below, the top of the grow cup.