Total light output needed for each plant shelf :T8 set-up
I'm looking for advice. I'm designing and building my own plant rack. I'm growing woody cuttings/seed, vegetable starters vegetatively (also mature leafy veggies:lettuce,kale,micro-greens,herbs) and wheatgrass/sprouts. I want to use T8 48" 32W (2850 lumens each)bulbs in an industrial reflective fixture. My question is this:
I read that 20 watts per square foot is a good average for indoor growing with florescents. I know that a lumen figure needed for an 8 sq. ft. shelf would be a more accurate take on the amount of light needed per shelf. If each shelf is 4'x2'(8 sq. ft)that means i need 160 watts per shelf. One question is what is the total lumens needed per shelf? If i use the watts figure per shelf, then if i went with a 2 fixture (2 bulb) ea setup - that would be 128 total watts (or 11,400 lumens)The cost for both fixtures is around $76.00.
Another option - I can get a 3 bulb fixture from Gardeners Supply that are seconds (cosmetic scratches, dents) for $10.00 each. If i put two of them per shelf (6 bulbs)that would be 192 watts total per shelf (17,100 lumens). Which setup would be best or is there another option that is better to supply the needed light for a 4'x2' shelf of total growing space?
Another question i have is that I was thinking of using a 5000 K bulb in the fixtures. I know cool bulbs are 4100 and that "daylight" bulbs are 6500. They list the 5000 as a full spectrum bulb. I thought the 5000 would be a good all around choice for each bulb for the leafy vegitative plants that I'm growing. Is this right or do you recommend the 4100?