rockwool cube size for vegging?

I am going to start from seeds and then transfer to rockwool cubes in an ebb and flo system until preflowers appear. I realize that it is somewhat strain dependent, but can anyone give me an idea of what size cubes to use that will allow the plants to reach preflowering stage? How big can I expect them to be at this stage?

I will then move the best plants to bigger containers under HPS lighting.

thanks much

1 inch to 1 and 1/2 inch cubes will be perfect. As far as how big will they get will depend on what strain you are growing. Go with the mentioned sizes and you will be fine.

Thanks,


I realize the 1 to 1.5 cubes will be ok for the seedlings, but I mean from there until pre-flowers appear at about 6 - 8 weeks of vegging. Right before I switch to 12/12 under HPS lighting.

Thanks Again

It depends on how large you want to make them, the hydro system I just constructed for myself (ebb and flow) uses 6" rockwool cubes, but you could easily use 4" (which are easier to flood anyway). Either will take most plants all the way through to harvest.

yah u could easily plant your seeds in a plug in a 4" rockwool cube and never have to transplant them throughout the entire harvest which is a good choice since transplating is messy and strains the plant

It was my intention to then use a 4" cube for the vegging and then place that cube on top of a 5" pot with hydroton rock (sort of like placing a cube on a slab) or a mix thereof and use a top feed system on the "stack" through harvest.

Has anyone done this or it is overkill? Am I'm worrying too much about root space when it comes to hydro? After all aero or NFT uses no medium at all.

Thanks as always for your inputs.

using the pots with the hydroton MAY be a overkill but honestly couldn't hurt and would promote good drainage.