Grow Box Dimensions to Maximize Efficiency Question

[TheMajestic]

Hello to all MP members. First off let me say what an interesting and knowledgeable board you guys have here. I have been reading a little here and a little there for the past couple of months so I know the basics of growing weed. I have a couple of quetions, however, concerning how to design my grow box to maximize efficiency and output in my grow. I suppose these kind of questions should be directed at Mutt, as I hear he is the design guru of grow cabinets, but I will consider everyones responses. Since I am new to this I want to start with a 400 watt HPS light and a cabinet that is 9-10 sq. ft. (give or take a couple sq. ft.) I am a carpenter by hobby so I will be building my own cabinet. I read that a 3x3x6 grow box is most commonly used for a 400 watt light, do any of you guys agree with this statement? Is there a better, more efficient set of dimensions that will maximize yield with a 400 watt HPS while staying around 10 sq. ft.(say 5x2 or 4x2.5) Second, and perhaps my main question is how many plants could one comfortably fit in a space this size? I don't want my precious plants to be cramped, but naturally I want to fit as many as I can. I heard one time the 1 plant per sq. ft. is the general rule, but I am skeptical of that number. Sorry about the length of this post for such ridiculously simple questions, but I wanted to make myself clear. Any comments are greatly appreciated, and I will definitely make my future posts smaller in length.

 

[cyberquest]

main thing you need to take in to consideration is lumens per square foot and temp.
they say that 3000-4000 lumens per sq foot of canopy for veg and 5000-6000 for flowering.
so to optimize your grow area you would want 4000 lumens per square foot for veg and 6000 lumens per square foot, to get optimal grow.

so as far as cabinets go, if you have a 4x2 then your square foot is 6. a 400w HPS puts out 50,000 lumens ( mine is high output and rated at 53,000).

so 50,000 divided by 6 = 8333 lumens per square foot, more then enough. so a 10 square foot cabinet would give you 5000 lumens per square foot, also plenty of light for good growth. that means you could go as big as 15 sq ft and still have the required 3000 lumens per square foot, but 5000 lumens per square foot would produce maximum lighting to them.

they say that Metal Halide lamps are better for the veg stage, they produce a more blue spectrum of light, and the HPS is best for flowering, BUT a HPS will give you good all around grow.

hope this helps you, good luck with the grow and i look foward to seeing some pics of your cabinets.

 

[TheMajestic]

Okay, I understand what you are saying. The particular Light I am planning on buying from my local hydroponics store is an HPS/MH system with a digital ballast that comes with a MH bulb that produces 35,000 lumens (35,000/4,000=8.75 sq. ft.) and an HPS bulb that produces 55,000 lumens (55,000/6,000=9.2sq. ft.) So according to these figures 9 sq. ft. of grow space for the light I plan on buying should be sufficient. I plan on using the MH for veg and HPS for flower. So now I wonder, what about the different dimensions so that I can get the maximum amount of plants in the cabinet (without hurting my yield). Should I run a 3x3, 4.5x2, or some other combination? Just curious as to what you guys reccomend. How many plants would you guys reccomend putting in 9 sq. ft. of grow space or does that depend on what type of system I am using (i.e. sea of green etc.) Thanks again for any help.

 

[cyberquest]

well i guess you need to sit down and figure also what type of containers you will be using for your grow. you need 1 gallon of soil for every foot of plant height if i am not misktaken.

will this be a soil grow, or a hydro grow?

the sea of green method is used to grow smaller plants in a shorter amount of time that would produce as much yeild as larger longer grown plants. so you could grow 6 plants half the size, and produce just as much as one large plant.

the light sounds great for your grow, and if you are only planning on using one cabinet for growing then sea of green might be your best route. idealy you would be smart to add a small veg section to the cabinet for seed sprouting and seedling growth until they are ready to go under the powerful HID lights.

i think you should look at some of THE BROTHERS GRUNT collection of grow cabinets, they are very crafty at small grow enclosers, they even have a speaker box used for veg, very creative!

 

[TheMajestic]

It is going to be a soil grow. It seems 3x3 is a relatively common size grow cabinet so I am going to go with that for my first run. Still unsure on my height, probably 7 feet. I think I will veg 9-10 plants and hope to get 6 females into flowering (might not happen that way). I would like to use 5 gallon buckets for my plants in hopes that they will grow 4-5 feet tall (I may go smaller if I use the SOG setup). I think I will build a removeable vegitation chamber at the top of the cabinet. For my first grow however I would like my flower and vegitation chamber to be one and the same. Any thoughts on this? I have been looking at TBG's cabinets and they are very imressive. I hope mine can come out to be half of what theirs are. Thanks for the help cyberquest, if anyone else has anything to add please do. I look forward to learning more from you guys and starting to build my cabinet.

 

[cyberquest]

just remember that your first few attempts at growing are going to be more trial and error then anything. there will be many a seedling die for the cause, i had three that didnt make it this week, but that just freed up space for others.

nothing wrong with them being in the same cabinet, just make sure that there is NO light that can pass between the two chambers. veg will be on a 18/6 light cycle and flower will be 12/12. you dont want ANY light to disturbe the 12/12 flowering light cause it can kick it out of its flowering stages.

since you have your ideal number of plants in mind make sure you measure your buckets so that they will all fit in the cabinet.

i start my seeds (after germinated) in small 2in x 2in peet moss cups, then after they pop thru the soil they get transfered into 2 1/2 quart containers, then to the large pots. BUT i am still new to all this too, i sit up everynight readin and readin and readin trying to learn everything i can.

its good to go thru peoples grow journels cause you can see some of their trials and errors and maybe avoid it with your grow.

what type of soil do you have in mind? i use MG which most growers stay away from cause its so high in N (nitrogen) and tends to burn the plants if introduced to any other nutes so i just give them plan water.

like i say i am still very new to all this too so i am still learning right along with you. i am flowering my first one now and she has only been in there for two days but we should be able to verify shortly she is in fact a female. we got pre flowers but still not quit big enough yet to determine.


and yeah some of you more experienced growers can chime in at any time now and make sure i am giving good advice here.....

 

[ch3117ho]

need help to start growing my own weed

 

[ch3117ho]

I all so am new to this and need help to get stared.It sounds like you know what you are doing.Just seeing if I could give me some help

 

[cyberquest]

this forum is full of information. i dont know that much really, what i do know is just from reading other members posts here on this site.

sitting down and pulling one all nighter would leave you with more knowledge then i could ever give to you my friend

 

[ZMAN]

6, 3 gallon pots would fit nice

 

[llamaman]

Cyberquest- Your information has been really informative and helpful. But, I have one question on your figures. You have said a couple times that a 4x2 grow cab = 6 square feet. Well my friend, sorry, but 2x4=8 sq. ft. doesn't it? Will this effect your figures?

I too have a 400 w MH/HPS light set up, but am seriously considering changing to a CFL set up for at least the first few weeks due to heat and cost factors. I'd rather have compact plants than long stretched out ones.

Thanks everyone for their input

The Llama

 

[cyberquest]

you are correct , that was my mistake. i have two rooms, one is six sq ft the other is 8, my HPS room is 8 sq ft, i think my fingers just get ahead of my mind sometimes. :rofl:

so correction to my math would be: 50,000 divided by 8 sq ft = 6250 lumens per sq ft. still more then enough for flowering.