Rockwool slabs

I have never used slabs before do i cut out the bottom so the water can drain through to my tray. I am using a drip system by the way 3 inch thick slabs with the white plastic covering it. ''Grodan'' is the brand of the slab.

I think the slabs are most commonly used to go under a set of grow blocks... i have not seen them being used as the sole medium.


*one post from #420 got to make it a good one...*

thats what i have now is grow cubes but my roots are all ready growing through after 2 weeks i have the 6x6x4 inch cubes i just bought the 3x8x48inch slabs to put under it thats what one of my fellow grower told me to do.