The setup I referenced above uses 4 COBs to produce 110 PAR W for 6 sq. ft. If I were flowering in a 4x8 space, I would need 6 of the above fixtures, for a total of 24 COBs.
If I am looking for 50-70 PAR W for veg, wouldn't that mean that I would need to halve the setup above, for a total of...