What would you use

[Galavant]

I am setting up my first medical cannabis grow. I can do 6 plants in bloom with my limits and other constraints. I want to do a scrog. My screen will be 60"x30" which is 12.5sqft. The grow will be from clones, and the strains I will be using are both 9 week finishers. They are Sleestack, and Buddha's Sister. The grow will be low pressure aeroponic. Each strain will have its' own segregated reservoir. Nutes will be MaxiBloom, with maybe Kool Bloom or another PK booster at the end.

I have a two questions:
1. Would you use one 1000 watt hps, or 2x 600w hps for flowering on a 30"x60" screen? Maybe another setup? What and why?

2. In your opinion, can the clones fill the screen sufficiently (~80%, 1.5-2sqft each plant) with 6 weeks total for root and veg? Veg will be under CFLs at approx. 4500 lumen/sqft.

Any other comments, questions or concerns are welcomed!

 

[JJ Bones]

Re: What would you use....

A 1000w or two 600w would be overkill, unless you dim them down. You'll want around 625 watts in that space.

6 weeks of veg for clones should be more then enough.

 

[Galavant]

Re: What would you use....

A 1000w or two 600w would be overkill, unless you dim them down. You'll want around 625 watts in that space.

6 weeks of veg for clones should be more then enough.

Oh wow, I didn't think I would hear "overkill" and lighting in the same context! 2x400w hps on dimmable ballasts@ 75% would be 600w, or 2x 600w @ 50% would be the same. Would there be any significant benefit to one over the other assuming they would always be run at lower output? I know the 600w are supposed to be the most efficient, but do you loose effiecency running at less that 100% output?

 

[JJ Bones]

Re: What would you use....

Two 400w ballasts run 100% would be great. 50w-65w per sq ft is the general goal.

Yes I would say you lose some efficiency but it's not bad.

 

[Galavant]

Re: What would you use....

Two 400w ballasts run 100% would be great. 50w-65w per sq ft is the general goal.

Yes I would say you lose some efficiency but it's not bad.

Excellent. Thank you for the input. I can get two 400w or 600w HPS setups for nearly the same cost, but I do think being effectively one small 30"x30" screen for each lamp, I will probably want to run the lights very close to keep a compact light foot print. The 400w might be the ticket for that. I have one 8" 200 cfm duct fan, and I imagine keeping 2 400w HPS's cool shouldnt be a problem for it. Is there really much linear benefit to jumping from 50 or 60 watts per sqft to 90-100? I would imagine the is a point of diminishing returns.