Smallest possible cab...400w lumatek...How stealthy and small can i go?

upinchronic1

Well-Known Member
Ventilation- 4 54cfm computer fans
-240cfm panasonic whisper for cool tube
-comair exaust fan (dimmed to silence, about 70 cfm)

With this info, what is the smallest dimension of a box i could stick my 400w lumatek? :confused:
 

Budsworth

Well-Known Member
I've got a mini cab that measures 2' deep X 3' wide X 48" high and it gets pretty warm. I've got it backed up to an A/C and the temps still reach 85%. The palnts do OK in there. Any more than 4 palnts and it gets crowded. My 400w is cool tube w/ fan intake. I would go any smaller. Hope this helps.
 

smokinjs

Well-Known Member
if you have adequate venting, you can go as small as you want, its ok if the plants rub up on eachother. ive got a mini cab going right now, like 1ft by 1 and a half ft. 4 plants. its working out good
 

upinchronic1

Well-Known Member
Nice, so what all do you have for ventilation, i was thinking of dimensions very close to that but was hoping someone would say i could go smaller.
 

specialkayme

Well-Known Member
Why would you want a 400watt hps in such a small space? Seems like over kill to me. 'The Grow Bible' recomends 50 watts per square foot, and most people on here recomend 10,000 lumens per square foot. If you put a 400 watt in a 1'x1.5' space you would be using 5.3 times the light recomended by the book and about 3 times the light max recomended by most growers. Your plants wouldn't even be able to use that much light. Just seems like a heat nightmare and a drastic overuse of electricity to me.
 

upinchronic1

Well-Known Member
Yeah good point, i dont want to waste to many lumens, put then you got to take into acount what happens to lumens as they travel a foor or two down to the plants then another 3 feet to the bottom buds of a plant, they dont stay constant. so my question remains...
 

upinchronic1

Well-Known Member
if you have adequate venting, you can go as small as you want, its ok if the plants rub up on eachother. ive got a mini cab going right now, like 1ft by 1 and a half ft. 4 plants. its working out good
nice, nice, and let me ask you what you have for ventilation.?
 

specialkayme

Well-Known Member
Yeah good point, i dont want to waste to many lumens, put then you got to take into acount what happens to lumens as they travel a foor or two down to the plants then another 3 feet to the bottom buds of a plant, they dont stay constant. so my question remains...
Wait .... what? Traveling two feet .... then another three to the buds ..... were you planning on making a five + foot grow box? If so, that's not a small grow. Lumens do disipate over distance, that's true. But you can get plants much closer to lower wattage HPS lights because they don't put off that much heat and don't harm the plants. Putting a 150 watt hps a foot away from the plants doesn't disipate that much light. Especially in a small grow. Putting a 400 watt hps a foot away from the plants will give you the same effect on the plants, while using about three times as much energy. If you think you are compensating for disipating lumens on a small cab growth by putting in 4 x as much light as you need you are way over compensating.
 

upinchronic1

Well-Known Member
Wait .... what? Traveling two feet .... then another three to the buds ..... were you planning on making a five + foot grow box? If so, that's not a small grow. Lumens do disipate over distance, that's true. But you can get plants much closer to lower wattage HPS lights because they don't put off that much heat and don't harm the plants. Putting a 150 watt hps a foot away from the plants doesn't disipate that much light. Especially in a small grow. Putting a 400 watt hps a foot away from the plants will give you the same effect on the plants, while using about three times as much energy. If you think you are compensating for disipating lumens on a small cab growth by putting in 4 x as much light as you need you are way over compensating.
Yeah i was just giving an example. Say my box was three feet wide, by 4 feet high by 20 inches deep. that light is traveling about 4 feet to each corner of the box, to the bottom of a 1 foot pot, so without the pot about, well, alittle over a foot. You have to think coverage, not nescesarly hight. Im not sure exactly what happens to lumens as it travels but id say by 4 feet its getting way down there. Plus it has to penitrate the colas on the inerside to get to the ones on the outer perimiter, cause my box, i can garentee will be stuffed, sardined if you will. Question remains...
 

specialkayme

Well-Known Member
Your still concerned with square footage, not volume. Your concern is to get 10,000 lumens per square foot, not 10,000 lumens per cube foot. The four foot high part is irregardless. Plus, your thinking is somewhat crooked. If your height is four feet, your pot will take up eight inches or so, posibly a foot. You don't need to light your pot, doing so is irresponsible. so a four foot grow becomes a three foot grow, one foot of which will take up your lighting. You don't need to illuminate your bulb, for obvious reasons, so a four foot grow then becomes a two foot grow. Your plants need light in the canopy, not the underside, so your plants really only need lighting on a one foot hight. So it doesn't matter how packed you are going to make that cab, it's still only a three foot wide, 20 inch deep, and (at maximum) one foot tall space that you need to illuminate with that hid. 400 w still is way to much of an overcompensation. you won't ever need that much light in that small of a space. At max I would say a 250, but that's just me.
 

upinchronic1

Well-Known Member
My thinkings crooked? how so? have you ever heard of the pathagorean theorom? that would be it works like this a squared plus b squared = c squared, a being two feet from edge to light in the middle, b being three feet down the wall to the pots and c being the unknown distence from light to pot edge. thats 2 squared plus 3 squared = c squared, or 4 plus 9, which is 13 = c squared wich is rufly 4. i want all buds to be getting optimal light, inturn optimal weight. And yes light needs to reach those pots as i will be using ALL the space to my advantage and lsting like a motherfucker.
 

specialkayme

Well-Known Member
First of all, relax there hot shot. You asked for help, people are giving it. If you don't like it, don't take it, no need to get defensive and rude.

Second, no, lights don't need to reach the pots, light needs to reach the PLANTS. The pots arn't growing, the plants are. You can lst all you want, but if the pot is six inches high, why do you need to light up the bottom of the pot? The top is understandable, but not the bottom of it. And your pathagorean theorm can be used on large grows, like room sized, but it really doesn't matter on small grows. When your grow space is 10 feet wide and you are putting the light five feet away from your plants, yes that is a big difference of over 2 feet of light travel from the edge of your grow to the distance traveled right under the light (light placed in center of room means light travels five feet to closest wall ... 5^2 + 5^2 = 50 .... sqrt(50)=7 ... 7 - original 5 = 2 more feet of travel). Big difference and something you need to compensate for. On small grows, like the one you asked about in this thread ("Smallest possible cab...400w lumatek...How stealthy and small can i go?") it really doesn't matter. When you are growing in a 16 inch by 18 inch square area and you are keeping your lights 8 inches away from the light, it doesn't make that much of a difference. The light is placed in the middle, so in the center it has to travel 8 inches. The distance from the closest wall is 9 inches. Your wonderful theorm then tells you to hit the furthest wall it has 12 inches to travel. You are talking about 4 inches. The lumens arn't going to disipate that much that quickly. If normal people are going to use a 150 watt and you think that isn't enough, fine, use a 200, or a 250. But a 400 just uses way mroe energy than you need and creates much more problems in small spaces.

But again, if you don't like my opinion don't take it. I don't really give a shit. You just asked for help and I'm giving my two cents.
 

upinchronic1

Well-Known Member
just trying to explain really, your the one caling my thinking crooked, and being a smartass calling the theorum mine and all. Idk anyone want to differ? 250w vs 400w for a 4foot high 3 foot wide 20inches deep area, with ventilation covered.
 

upinchronic1

Well-Known Member
oh and i dont want to go tiny, like 1 by 2 by 2.5 or anything like that, i just want to know how small i can go with out heat being an issue, if i have a couple extra lumens then who cares? i will have an optimal enviroment for optimal penetration, thc development and bud density. again im not tryig to be a smart ass, but get an answer to what im trying to get at.
 

specialkayme

Well-Known Member
I hear you. Sorry if I came off strong, your post earlier seemed to be a little bit of an attack. I got a little tweaked by it, no biggie though. I wasn't calling your thinking wacked or anything, just a little crooked, as in not 100% in line with what alot of other people say and think on here. It wasn't an insult.

I think I know what you are looking for a little better. I thought you were looking to put a 400 watter in a super small grow. But now I understand that isn't the case. Personally, I have experience with small grows, not micro though. I've never used anything over a 250 though, and have never grew more than four plants at a time. but then again I don't sell or smoke that much, so I don't think I can really help you.
 

upinchronic1

Well-Known Member
Hey man, its all gravy. Yeah ok, i also thought you were attacking my thinking so i was like whoa dude chill, but i can also see that wasnt the case. But yeah, well what was your 250 cab like, dimensions, ventilation? It would be good to base off.
 

specialkayme

Well-Known Member
I don't use it anymore, but I had a 5' tall, 2' wide and 2' deep cab. Vents were done with a passive intake and an 8 inch vortex fan for exhaust. It did the trick, but was a little more bulky than I would have liked.
 
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