In S. Cal, I have a grower that has been using liquid gypsum and liquid bonemeal in a rockwool grow. The results are been pretty amazing to say the least. Provided that those growdan block sit on a larger one, the runoff of the gypsum and bonemeal has been a minimum. And since they drain to waste, the runoff is a non issue.
I had my doubts, but hey, what ever works! There are some samples to try in the next couple of weeks, stay tuned! The grower says it is the best he has ever grown and the buds are like rocks! Sound familiar?
OH IF A MAN TRIED
TO TAKE HIS TIME ON EARTH
AND PROVE WHAT A MAN IS WORTH
I WONDER WHAT WOULD HAPPEN
TO THIS WORLD
-Harry Forster Chapins' Tombstone