rockwool slabs

when placing the big rockwoll cubes onto a slab, do you just set it on top or does it need to go "in" the slab ???? have had a system (top drip) for awhile and finally decided to use it. i have roots coming thru the lg cubes. just wondering since the 1'" cubes actually fit into the 8" (?) cube. Also is one slab enough or will the roots go thru. I'm startin to like dirt more and more.....

i grow dirt and love it but i hear hydro is so much beter..any ways are you using the 4" cubes or what type of slab is it cocunut ? cus if its just a slab then it can sit right on it and the roots will grow in to it...

thanks kahtn......yeah its just another rockwool slab. so as you said i just set them on top. thats what i was hoping for. I also have used dirt/saphgum exclusively but have also heard the wonders of a hydro system .got a 21 plant top drip sysyem set up so i'll let you know if its worth the trouble. just seems dirts soooooo easy. feed and forget....lotsa stuff to stress with hydro...either that or i'm stressin stuff i shouldn't. we'll see....keep you posted