rockwool grodan
 

how long do you have to soak rockwool before you can use it,should it get soft or femain firm?got some but never used it before and theres no instructions with it. thanks in advance

It will soak up water just like a sponge (right away), so no need to soak it. It's already sterile also, so no need to do anything special to it. You don't want it sitting in water because it will remain to saturated, so just dunk it in water then lightly shake off the excess water, then place seed (or sprouts) in it. I have a water spray bottle with just water in it, that I mist the rockwool once in a while when it looks like its drying out. Once they have sprouted you will want to use a diluted (like 1/2 to 1/3 or even possibly 1/4) strength nutrient solution in place of water. Although I would not spray it on with the spray bottle, it might burn the delicate early foliage.