What is the optimal # of 4" rockwool cubes on a rockwool slab?

Hey folks,

For those who may have taken the above approach (4" rockwool cubes on rockwool slabs), how many plants would you recommend be placed in the slab - 3 or 4?

I see most setups use either 3 or 4, and I'd love to know if having up to 4 plants will leave enough space for the roots to raise the girls to be tall enough. What is "enough"? I'm targeting about 4' tall plants for an indica strain that got to be 4' feet tall when grown in 3 gallon pots.

Appreciate your input in advance!

So... nothing?

I used to use the 12x36" slabs & ran 3 plants in 4x4 blocks 6x6 blocks would give you slightly greater root area if you were to run 4 plants to a slab I've never tried it but see no reason why it wouldn't work

horribleherk said:

I used to use the 12x36" slabs & ran 3 plants in 4x4 blocks 6x6 blocks would give you slightly greater root area if you were to run 4 plants to a slab I've never tried it but see no reason why it wouldn't work

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I'm already in 4x4 cubes and trying to avoid using larger cubes. This is why I'm looking at the slabs. I'd really like to understand how much of a difference it would make to have 4 plants instead of 3 plants per slab. If it's marginal, I'd be happy

I do 3 per 6" wide, 4" tall slab. And then I'll do 4-5 slabs per 4x4 of tray. I stagger the slabs to fill out the tray better

Aeroknow said:

I do 3 per 6" wide, 4" tall slab. And then I'll do 4-5 slabs per 4x4 of tray. I stagger the slabs to fill out the tray better

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Is that the 36" long slab?

Ingvar said:

Is that the 36" long slab?

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Yup. If they made 4'ers i would do 4 plants per slab