400w cab design and development~help!

[smotpoker]

hey i;m in the beginning stages of a design for 400w hps flowering cab.

My first question is knowing that 50w per sq foot is ideal, would i be better going with a rectangle~2x4, or more of a square~2.5x3? this question is about light distribution, whats the most effective route?

my second question, what is an appropriate distance to keep my light from the plant tops? Is it different for an air-cooled vs. none air cooled?

my thrid question, i want to be able to get 4-8 ounces out of the box pre round, is this reasonable? will a 400w hook up this kind of intensity? (keep in mind i have no idea how long i will be vegging, or what strain they will be. it will most likely be a constant experiment.)

keeping in mind my 4-8 ounce target, would i be more succesful with a sog or fewer, and larger plants jogged down?

thanks for any help i can get.

peace,
smotpoker

heres a pic of a JOGGed plant grown by puthekniveson @growkind.com

 

[mpd]

The short answer is you can yield up to around 400 grams on a 400 watt system, but that would be a tree style grow. For a cabinet application, I assume you will be running a SOG or SCROG type set-up. Expectations for finished bud production should be in the 175 grams to 250 grams per square foot of growing area in the cabinet.

If you wish to optimize your lighting, may I suggest you give consideration to running a GE ceramic metal halide on your 400 watt hps ballast? These lights seem to create compact plants with very dense foliage and dense foliage provides the fuel for massive bud development later in life. Having said that, a lot of people swear by the Eye Hortilux bulb's performance. Eye Hortilux, Agrosun Gold Deluxe, ceramic metal halide - pick your poison. I have run the Agrosun and it is a great bulb, and will be doing a full-scale comparison of the cmh against the Eye Hortilux shortly and will have a complete report on these issues in the fall.

In terms of a reflector, the reflector you bend should basically match the cabinet dimensions. You CAN bend your own custom air-cooled reflector for about $50 in materials. I kid you not. I have no metal working skills whatsoever and I was able to bend a quality hood from a sheet of 26 ga. stainless steel. I would think an air-cooled hood would be mandatory for a cabinet, but then again, I don't grow in a cabinet, I grow indoors tree style with approximately 100 watts/sf. My first run produced around two (2) pounds of cured quality bud.

If you want to fix the exact height of your reflector get a light meter and set the light so it is putting out approximately 4,000 fc at the canopy level. To do it without a light meter, set the light so that you can maintain your hand at canopy level without your hand getting overly warm and you will be just fine.

My understanding of SOG operations is that they rely upon a higher density of plants per square foot (4 to 6 plants per sf has been repeatedly mentioned), with each plant being pruned so as to create a sea of single cola plants. There are some real SOG/SCROG junkies on these boards, so don't be afraid to ask people for their assistance.

 

[smotpoker]

thanks mpd.

do you know if a hortilux or agrosun bulb will work in any 400w ballast, or do the lights come with specific ballasts?

and this cmh light you speak of will run off an hps ballast?

thanks again

 

[ken]

a square area would probably be easier to light with 1 lamp, but it depends on the reflector.

mounting height will vary depening on ventilation, temperatures, etc, as mpd said use the back of your hand as a rough guide, it shouldnt feel hot where the plants are. its a good idea to have an adjustable mounting height, so you can raise the light as the plant grows (just dont forget )

8 oz shouldnt be unrealistic for a 400w, you could get that or even more with good clones.

as for growing style, its up to you, when done well, if you fill your space with buds, you should get a similar yeild no matter how you did it. although veg times vary.

there are advantages & disadvantages to any style of grow.

if you can get enough clones easily, and dont mind the high plant count, go sog.

if you can veg quickly in a nice hydro setup, one plant could do just as well, with only a few weeks veg.

a squarer grow area would be better if you plan on 1 plant, rectangle for 2, doesnt really matter for sog.

i'd rather buy a good hydro store reflector than make one, i've seen better results with those than homemade efforts. it will cost 2 or 3 times as much as one you could make, but its worth it for a tried & tested properly designed reflector. bad reflectors can create hotspots that burn your plants & provide uneven light distribution.

btw: i like to take 50w per square foot as a minimum, for small cabinet grows, as your aim should be yeild per square foot, rather than yeild per watt, when space is limited. you could probably get better results with a 600w lamp, and they normally only cost a little more than 400w.

 

[smotpoker]

thanks ken, what sort of ventilation would be best? i am looking at a squirrl cage fan. 265 cfm? would a couple computer fans be suffiecent? thanks again...

 

[smotpoker]

hey ya'll would i be better off going with a reflector like this one :

it would have to be air cooled and it would be connected to my main exhaust, having only the one exhaust to vent the light and the cab.

or would this work sufficently? i would put the exhaust next to the light and no air cooled goodness. but 40$ cheaper

also, will the eye hortilux make a noticable difference from the standard 400w hps light?

 

[smotpoker]

cfm rating?

cfm rating?

i have another question....

So far my box is looking to be between 6 and 8 sq ft. I bought a pyrex bake-a-around tube(4") to make an aircooled light with. No reflector going to be used, just mylar on the walls.

I am going to buy an inline fan. What cfm would be most effecient in my space? i have as options, 392, 257, 243, and 289.



the first two look like this, and are made with galvanized steel.
145$ for the 257 and 190$ for the 392.

the second two are made with thermoplastic shells.
139$ for the 243, and 169$ for the 289.

any opinions? would the steel or thermoplastic construction make a difference?

ordering from this site.

peace

 

[Einsteinguy]

Hey smotpoker

Looking good. Just got a Sunsystem 400 HPS
wow this thing is bright. Using inline fan like in pic. Hope it keeps it cool enough.

Einstein

 

[smotpoker]

right on einstein!


i cant wait until my 400 is up n' running. It will be better than my 150 for sure.

what cfm rated fan did you get?