# rockwool grow blocks hydro question



## 707NewGenGrower (Jul 25, 2011)

im thinking about trying a flood and drain with rockwool grow blocks 4'' by 4'' by 4'', but i was worried about the limited root space in the 4'', i was wondering if when the roots start to come out the bottom of the cube, could i but another fresh cube under it and will the roots grow into? does anyone see problems with stacking cubes? will it even work? thanks


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## Hushpuppy (Jul 25, 2011)

I've never used the cubes myself but I can see a problem with stacking them as that would make them top heavy, and yu would have to support them some way. Plus the roots would be coming out the sides as well as the bottoms. There is a rockwool slab that yu can get to place under it that will allow the roots to grow into a wider bottom and spread out. This will weld the block to the slab and make them much more stable. I've seen a lot of people in the smokers' magazines use them with great results. If I used that medium, that is what I would do. Either that or a specialized container with hydroton surrounding the cube but with enough holes in the bottom for the flood to get into it...It depends on if yu are wanting to grow large plants or smaller plants. All of the RWcubes in F&D that I have seen in the mags, the people were growing relatively small plants that were harvested in a shorter flower phase. I think that is because the roots don't grow as prolific as in the containerized mediums and therefore the plants don't grow as big, but finish sooner than the more "naturally" grown plants. Everyone that I have seen growing larger plants grow in some level of container that allows the root system to get much larger which allows the plant canopy to get larger. I hope this helps. green grow mojo


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## pcduck (Jul 25, 2011)

I have stacked mine with no problems. Set my clones right on top of the big cube, the roots grow into the big cube with no problems. The 3 x 3 x 2.5 on top of the 6 x 6 x 6


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## stemjosh (Jul 25, 2011)

they actually sell the hugo cubes for that purpose but i use 4 in blocks in my ebb and flow setup and fill the remainder space with hydroton it anhcors them down pretty good and its reusable rock wool gets expensive


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## 707NewGenGrower (Jul 25, 2011)

thanks pc thats exactly what i wanted to hear, thank you everyone for your input
happy growing!


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## Hushpuppy (Jul 25, 2011)

pcduck said:
			
		

> I have stacked mine with no problems. Set my clones right on top of the big cube, the roots grow into the big cube with no problems. The 3 x 3 x 2.5 on top of the 6 x 6 x 6


As I said initially, I have never used those. Do yu have any trouble with roots coming out the sides and drying out from being in the air? How big do yer plants get in those cubes? do yu have to tie them to keep them stable or do they stand ok on their own? I can't see how a good size plant can stand on its own and be stable in just a 3x3 on top of a 6x6 block


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## pcduck (Jul 26, 2011)

Hushpuppy said:
			
		

> As I said initially, I have never used those. Do yu have any trouble with roots coming out the sides and drying out from being in the air? How big do yer plants get in those cubes? do yu have to tie them to keep them stable or do they stand ok on their own? I can't see how a good size plant can stand on its own and be stable in just a 3x3 on top of a 6x6 block



I keep the plastic on so that the roots do not grow out the side.
They get just as big with just as much to tie as my DWC or my organic smart pots grows.


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## Hushpuppy (Jul 31, 2011)

I will have to remember that for future grows


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