Square or rectangular growroom area?

[blackone]

I'm wondering what you people think is best for a single 400 or 600 watt hps, square or rectangular? And what would be your dream dimensions? I guess it also depends a lot on the reflector?
I'm thinking of building a 600w box if I get a chance to move into a bigger place.
Obviously stuff like how many pots of certain available sizes will fit is also important;p

 

[Truth]

I'm wondering what you people think is best for a single 400 or 600 watt hps, square or rectangular? And what would be your dream dimensions? I guess it also depends a lot on the reflector?
I'm thinking of building a 600w box if I get a chance to move into a bigger place.
Obviously stuff like how many pots of certain available sizes will fit is also important;p

well square is best since maximum coverage area for 400w is 3x3. You can always go slightly over that to fit a few extra plants or let other plants stretch out..but these areas will not receive optimal lighting.

 

[clowntown]

Why/how is the maximum coverage area 3x3 for a 400w? Are you figuring this by the "minimum desired WPSF" math? Those are just guidelines to go by and certainly not requirements; and it's much easier to quote "3x3" than "2.75x3.25" or something.

blackone, I think you really answered your own question pretty damned well.

With most reflector designs you'd optimally want a rectangular room since the side, curved reflective surfaces will generate a more rectangular pattern than a square pattern. This is especially true for air-cooled reflectors.

Assuming you're using a reflector at all; if using a hanging bulb for vertical/side lighting, I suppose a round room would be optimal. If that's not practical, the next best would be square.

 

[blackone]

Thanks - I've never used an HPS so I haven't been able to see the "light volume". Should the longest dimension be parallel or perpendicular to the reflector? Most rectangular growrooms I've seen have been using a parallel setup but from your description perpendicular might be better?

 

[clowntown]

Yes, it's a bit counter-intuitive. With most reflector designs, perpendicular will get a more even light distribution with less light having to be re-reflected from the walls. This varies depending on the angle (and depth) of the side reflective surfaces, height that the reflector is hung at, etc, so YMMV. But in most cases, perpendicular will result in a more even light output.

A very good example of this is the EconoCool reflector:

Do you see why?

 

[blackone]

Well looking at the picture it seems like quite a lot of light would be bouncing off the long sides as "crossing" rays at shallow angles.
But it's hard to say just looking at it Need more info on depth, angles etc.. I guess it's better just to test it out.

 

[clowntown]

If you get a reflector similar in design to what I'm referring to, you'll see what I mean when you see the light footprint. Sometimes it's not very easy to spot with the naked eye, but most of the time it is.

I used to run an EconoCool in a rectangular closet, before moving into a HydroHut. I initially configured it parallel since the ducting fit better that way, but later realized that perpendicular worked better although it was a bit awkward to place the ducting that way.

 

[blackone]

Thanks. I'm considering either a cheapo BLT reflector (http://hanfburg.de/store/product_info.php?cPath=1_17&products_id=2520), cool tube or cool shade. If anybody has any info on the light distribution patterns of these it would be greatly appreciated.

 

[clowntown]

I like my Cool Tube okay, running in a small closet with a 250w. But I love my Hydrotek Silver Star from some preliminary testing I've done. I haven't had a chance yet to use it in a grow yet, but it appears to shoot out a nice even pattern and is very well built.

So far I've only owned three reflectors, but I've seen plenty more in person and in action... and IMO the Silver Star beats everything else without a doubt. I hear Hydrofarm Daystar's are pretty nice for smaller spaces, though.

 

[Guest]

Clowntown...........You sure shootin out a lotta good info and pics to go with explanations here lately and I just wanted to say keep up the good work helpin folks bro..........For me........I never used a reflector in my life cuz I did vertical bare bulbs growin trees krusty style but had major a/c and heat extraction up high goin out of the room thru a scrubber and a thermostat......The most lumens generated are of course without a reflector,but everyone`s gone to air-cooled and I guess the best ones are as you say .......the ones that give the most dispertion throught the glass lens and even reflection downward, and yes I never understood how a lightbulb covers a square area but the reflectors are all rectangular........Kinda like 10 hotdogs in a package but the buns always have 8 in a pack...... ........ Good info dewd and PEACE...............DHF........

 

[blackone]

If you just hang the bulbs vertically won't half of the light just be directed upwards, making the ceiling act as a reflector? How would a purpose-build relector be worse than that?

 

[mrgrowmez]

hey blackone,
if you think about a bulb hanging horizontally half the light isnt shooting out its ass towards the socket its coming mostly from the sides because it has the biggest surface area..so hanging it vertically you woul assume that almost all the light is shooting out sideways and a bit downwards not so much upwards from the base of the bulb....at least thats how it seems in my head hehehe i havent had any experience with hanging bulbs maybe there is someone who can back this up??
cheers
MR.G

 

[blackone]

Well light shooting directly sideways would be even worse if the light is placed above the plants? It would have to bounce off the walls many times before reaching the plants.

 

[mrgrowmez]

im guessin if hes hanging vertically then hes growing trees up around his bulbs...at least i hope so otherwise of course your right thats alot of wasted light. not sure what krusty style is tho....

 

[Guest]

Sorry I did`nt clarify ..........Blackone........When you grow trees(like 4 huge plants in a 10x10 room with mega watt lights,plants that go to the ceiling which is Krusty style(you have to be an old head to remember a few to several yrs. back to the Krusty wars..lol.........)Anyways dewd,lights WITHOUT reflectors vertically suspended DOWN amongst the plants not above them gives off the most lumen output for your bulb as there is no UP on the lights only sideways..understand now?...I`ll be using cooltubes suspended horizontally about 10" above ebb and flow buckets next run.......My point was that lumen loss occurs with ANY reflector bar none and I`m sure there are countless folks here that will attest to that....Take care and ....PEACE.........DHF...........

 

[clowntown]

That is correct. Light intensity is lost at the reflective material (usually the aluminum insert; see how reflector manufacturers claim "95% reflectivity" and such), through the extra distance traveled due to reflection (artificial light loses intensity exponentially over short distances), and through any medium it travels through (i.e., glass lens). Krusty style with bare bulbs gets you the maximum bulb efficiency since you are outputting only "pure", direct light: non-reflected, no unnecessary extra distance, and no extra medium to absorb.

 

[blackone]

Definitely makes sense
For intensity loss: Intensity is inversely proportional to the square of the distance from the source (Doesn't matter if it's artificial or not, but to double your distance from the sun would not be practical) so it's not exponential.