'Commercial' scale indoor setup - ideas?

[littlefrog]

Another thread got me thinking that I should pick your collective brains... Here is the deal. I've grown in a 1500sq foot greenhouse for the last 6 years, with only a few plants under lights inside. Before that, for many many years I grew exclusively under lights.

We are moving (have moved) and due to my township being obstructionist, I've decided to convert my new pole barn into a growing area. Or at least part of the barn. It has its own electrical service (200A), mostly concrete floors (two corners are dirt - used to be horse stalls), and it is insulated with whatever insulation they use on pole barns these days - some sort of thin radiant barrier type, probably not a huge R-value but better than glass for sure. Barn is 48' x 30', I'll probably be lighting about half of that right now. There is a smallish gas fired unit heater in there already (going to try to hook it up next week), and I can build a dividing wall pretty easily so that I don't have to heat what I'm not using. Open ceilings so I can mount lights as high as I want.

So... For growing orchids and bromeliads, which have a moderate light requirement, I'm planning on using a few 1000W MH lights. I already have two 400W MH lights, I'll add those into the mix. Right now I'm trying to figure out what kind of square footage each fixture will illuminate, and at what height.

For growing the foliage plants (ferns, various small tropicals), I was going to go back to light carts and fluorescent fixtures. I have lots of T8 fixtures, but since I'm spending money, I have considered upgrading to T5's, but I'm not sure if it is really worth it.

So, given that background, do you have an opinion about what you would want in that kind of facility? What might you do that I haven't considered? HID growers, how high and how much area can I really light with those fixtures? Basically if you have an idea, I want to hear it before I start building this beast.

THanks

Rob

[Duane McDowell]

Sounds like fun!
I'd put a lot of thought into ventilation and drainage before getting too deep into lighting... Have you considered louvered doubleiwall Lexan panels in the roof for ventilation and supplemental light?
Also, if you can heat under floor or benches, you'll be glad you did!

[johnblagg]

a 400 watt mh lights a 4 x 4 area but actual square footage will be determined by the need of the plants grown ...a 1000 watt 10 x 10 but again determined by need of the plants and how far above them you are hanging the lights ....

I would say 1000 watts would be 5 or 6 feet above plants at least and could actually cover more area than 10x10 because you dont need that intense a level of light best way to tell would be a light meter under the light and mesure footcandels or lumens ....

I used a 400 watt Mh above phals last winter and had fair results but a bit of sunburn so 4 feet would have worked and possibly 5.

2 feet is the closest a 1000 watt mh could be due to heat issues alone and that is for a direct sun loving plant so 5 or 6 foot I would say minimum for orchids that are high light orchids

[RJSquirrel]

I think you should really look into the T5's..energy efficient so they dont cost you a bundle compared with HID or MH..
a 4ft x 2ft 8 lamp T5 Hi Bay fixture set up with 5000k lamps is = to 1 400w MH and cost 85% less to operate..I dont think I would refurb the T8's bec the parts,ballasts alone are almost as much as you can buy the whole T5 light fixture...159.00 to 200.00 bucks for a T5 8 lamp Hi Bay industrial light with 5000k lamps and a 4 x 4 area sounds about right..
another thing about the MH and HID is the heat load from the lights...LOTs of Heat might be good for you since you way up there in the frozen tundra. Now flourescents do have issues with starting up in cold weather so NEW rapid start ballasts HAVE to be used or they have hard time heating the lights up and wont burn the ballasts out....

[Oscarman]

Originally Posted by RJSquirrel

..LOTs of Heat might be good for you since you way up there in the frozen tundra....

Frozen tundra!Too funny.

Good thread Rob. Especially good as I wrestle with lighting choices for my room. Wow a barn, now thats a BIG grow room, almost Texan in size!

[littlefrog]

If it gets too cold for fluorescent ballasts to fire in the plant room, not much point in turning on the lights... *grin*

Would a 8 lamp T5 fixture light as much area as a 400W MH? I was under the impression they were pretty much straight down. And I thought the 4' T5 were ~50W per tube, so that is 400W vs 400W... Don't see how that would be cheaper to operate.

As an update, looks like since I can't seem to sell my old house anyway, I'm going to use the old greenhouse for this winter. But still need to do something for next year, so let's keep this thread alive.

[johnblagg]

actually they are pretty much straight down and still do not penetrate like Mh does and I agree if its 400 watts its 400 watts but when it actually comes to effeciency a 600 watt Mh is the most efficent per watt from what I read ....T5s are only better because they fit in smaller areas easier and dont need big reflectors ect ...actually the 400 watt mh lights up a 4x4x4 area its more cubic feet with them not so much square feet like a t5 seems to me to cover ....I dont think a bank of t5's three feet above your area is not going to be nearly as effective as a mh 3 feet above them would.Sometimes headroom counts.If I was growing on layered shelves then T5's would be a good way to get light on plants 12 inches under the shelves but on a bench I would not be so happy with lights suspended 12 inches or 24 inches above plants blocking acess to water and work .....

As for heat being a liability with mh.... in winter when I use lights instead of being outside the heat the mh puts out is actually helping to offset the heat bill so I am not using as much heat from other sources so that liability is not a factor in a large area where you would have to add heat anyways.