Quote Originally Posted by CesaroSumm
I'm doing a 4x4 tray ebb and flow 600 w hps.

My question is I currently have the plants 4inch rockwool that's it. Is this okay? Once the plants get bigger I will use a trellis to support them. My main concern is the root system, will I need to put something underneath the rockwool, or can I keep as it is? I've researched it quite a bit and I've noticed tons of different answers. I'm trying to build a consensus. Thanks!
Hello CesaroSumm and welcome to the boards.

Probably alot of different answers because there are alot of different growing styles. If you are going to grow SOG style (plants no bigger then 18" or so) you can place the RW blocks directly into the tray. But if you intend to veg for awhile and grow 3'-4'+ plants then you want to place a RW slabs in the tray and place your blocks on top of it, spaced to accomedate the size of the final plants.

While you didn't ask, I think a 4'x4' tray would do better with 1 kw HPS light.

Hope this helps.