Rockwool size? Best Size

Gotsmoked

Member
What size rockwool cubes are best to grow?
I had a grow (started with seedling in it) with 8 inch cubes(could have been 6 inch, been a while forgot) and my babies grew fast and strong(600w HPS). The roots were coming out of the cube by the 4th week and growing into the hydroton. Plant grew healthy and did not have any issues for the first month of growing. The cubes were a little expensive but I thought it was worth it because I wanted big healthy plants.
Then had a grow in 4 inch cubes (started the seedling in a 2 inch first then transplanted to 4inch) and my babies grew fast (then stopped after the 19 or so day and grew slowly) and they were strong. The roots were all blobbed up on the bottom of the rockwool. A couple of the plants got burnt from the light(which is weird because i used 400w HPS this time). So I guess I had the 400w HPS light too close but I am almost sure I had it the same distance I had on my other grow with the 600w HPS light. So its the 24 day and they look about the same size as they did on the 19.

So i was thinking that because the roots had nowhere to go, the plant grew slower than usual. Kind of like a plant can only grow as big as the pot lets it(transplanting). I thought you want the roots to stretch and search for that water. The heart of the plant is its root system; so I thought roots are what you work on first. Does anyone have any input on what size rockwool to use?
 

raw225

Active Member
are you using rockwool just buy its self as the grow medium?? if so then you need to buy bigger cubes! OR, do have them in a hydroponic system with the rockwool cubes surrounded by the hydroton rocks(like a hydro system works??
 
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