12x12x8 Bedroom grow 9 600w hps 4 400w mh 25 plants

So the past 3 years or so I have been trolling the internet between here, icmag, and a few other forums researching, sifting, and taking in as much of the vast knowledge that is already available out there. I feel the time has come for me to join in on the conversation as I am hoping to get some feedback and become active in the forum as I make a larger commitment to my growing. During those 3 years I have grown a few successful crops but this time things are going on a completely different scale. I am hoping to convert one of the bedrooms in my home into a 12x12x8 flowering room. I have another room of equal size which will be modified into a veg room. I am modifying my flowering room after a template I was referred to and can be found below:
He is running 9 600w in soil 25plants in ~9x9 area
https://www.icmag.com/ic/showthread.php?t=200490

Heres there basic rundown on MY setup:
12x12x8ft. area
1 ft walk space around each wall, giving an interior grow space of 10x10ft.
9 600w HPS lights arranged in rows of three. Rows are spaced 2.5ft apart in grow space with each light in each row being spaced 2.5ft. from another. These will be hung ~12-15" from canopy as each HPS bulb will be in an air cooled hood
4 400W MH on 4' light movers. These will be placed in between the rows of 3 600W HPS bulbs and hung ~9" from the canopy.
1 A/C unit which will be connected to ducting running through each of the 9 air cooled hoods and exhausting into a bigass carbon filter then out and into the attic.
4 16" oscillating fans positioned in the middle of each wall
1 850cfm exhaust fan
1 10" intake fan next to an intake vent in the opposite corner of the room from exhaust fan.

Now on to what I am growing.
I plan growing 25 plants in the 10x10. Vegging for 4-5 weeks depending on how everything goes once the ball is rolling. If they become too big and space is limited veg time will be cut if necessary. The plants will be topped and LST during veg and I am contemplating whether or not to use a scrog net at the turn for flower. I am not set on genetics but do know they will be clone only and nothing from seed.
I will be growing in soil and using, biobuzz with fix mix and cannaflora nutrients.
The ladies will be in 10gal smartpots and hand watered, an irrigation system will be used later on possibly, but as this will be the first run in this a room I like to have as much control of it as I can until everything is dialed in.


My concerns and questions for the room are this:

What would a sufficient BTU rating be for an a/c unit to effectively cool the 9 HPS bulbs and keep the temps down in the grow room?
Will 4 16" oscillating fans circulate enough air for all 25 plants? My concern here is the interior plants i know during flowering things are going to get hectic and I hope they are not blocked off from air flow by the plants on the outer limits.
Condensation issues with cool air over the lights? what should I look out for here?
Will space be that big of an issue? I know things will be tight, but as noted in the link above and many other threads I have seen, 25 plants should be manageable in a 10x10 area.


I am completely open to any and all input and would like to hear what you have to say. if you can answer my questions even better. I will try to get a drawing posted soon to clear up any confusion on the room design. If anyone has run a similar setup I'd love to hear about it. Thanks in advance for the feedback.

Id say that its a better idea to have ac hooked up to cool your room instead of your lights. A couple high cfm extraction fans should move air over your bulbs enough to get decent cooling. Especially if intake for them is from outside or somewhere cool. AC should be about 20,000 btu roughly 2.5 times what the space would need without a grow...the bigger the AC the less it needs to run.

It woulr be a good idea to have a few fans underneath the canopy moving air down below and also getting air moving for those interior plants. Lollipopping is a great idea when using 600s on big plants. Gets you better light to a higher percentage of the bud mass and also really helps stop shit like powdery mildew.

If you want to try something a little bit different I would highly suggest a Hempy bucket type reservoir in your pots and you can still use dirt up above. It increases growth by the nature of what kind of rootmass is built and keeps water/nutes supply constant. It can be as easy as a half inch hole about 3 inches up on each bucket and 3 inches of perlite or hydroton in the bottom of your buckets. It also makes it a lot harder to over water.


love your idea of throwing some mh bulbs in there for spectrum...ive found a mixture of hps and mh out performs only one spectrum.

Oh and id really suggest hanging your mh 400s vertically either in cooltubes or bare bulb. You get a much nicer spread that way and it really helps the buds that arent on the very top.

im jealous its been years since I ran a big show.

sounds like you got the setup part figured out . i would just get a mini split ac system.. assuming you have alot of room on you panel ? because thats going to be alot of watts ..6700 in lights alone? would love to see pics and progress you make on this project

Hi. I'm watching this thread. I am working with similar wattages. I run a mini split for cooling.

Shivaskunk said:

Id say that its a better idea to have ac hooked up to cool your room instead of your lights. A couple high cfm extraction fans should move air over your bulbs enough to get decent cooling. Especially if intake for them is from outside or somewhere cool. AC should be about 20,000 btu roughly 2.5 times what the space would need without a grow...the bigger the AC the less it needs to run.

It woulr be a good idea to have a few fans underneath the canopy moving air down below and also getting air moving for those interior plants. Lollipopping is a great idea when using 600s on big plants. Gets you better light to a higher percentage of the bud mass and also really helps stop shit like powdery mildew.

If you want to try something a little bit different I would highly suggest a Hempy bucket type reservoir in your pots and you can still use dirt up above. It increases growth by the nature of what kind of rootmass is built and keeps water/nutes supply constant. It can be as easy as a half inch hole about 3 inches up on each bucket and 3 inches of perlite or hydroton in the bottom of your buckets. It also makes it a lot harder to over water.


love your idea of throwing some mh bulbs in there for spectrum...ive found a mixture of hps and mh out performs only one spectrum.

Click to expand...

Thanks for the feedback! I really like both your ideas concerning fans underneath the plants, as well as the hemp style buckets. Do you have any links that i could do some more research on those type of buckets or grows where they have been used. I think I will use 2 or maybe even 3 of the smaller 6" oscillating computer fans for underneath the plants after your suggestion.

I see what you are saying about the A/C running to the room being more favorable than cooling your lights. So as it seems, I will have my A/c cooling my room and just have extract fans pulling air through the ducting over the lights to cool them. I read somewhere, not entirely sure where exactly at this point as there is just so much I've looked at, that it isn't smart to cool more than 4 lights per ducting. Has anyone else heard of anything as such? Or have any comments regarding the topic? I plan on running one central duct through all 9 air cooled hoods with an intake fan on one side of the room and an extract on the opposite and air cooled hoods in between. Is this plausible? The article I read I believe made note to concern that the issue with cooling more than 4 lamps is that the hot air pulled off lights 1,2,3 doesn't necessarily cool light #4 as it passes over. I am kind of hung up about this issue. Would it be better to run a separate cooling duct for each row of 3 lights? Or is one for all 9 acceptable? When choosing an intake and exhaust fan for the air cooled hoods ~ how much cfm am I looking for in each. Can I simply calculate the area of the cylinder and base it off that?

I'd love to check out some of your bigger grows shiva if you have any journals or logs I'd really appreciate the links =)
also any good links on light cooling would probably be beneficial at this point too.

Also as for the MH I will be of using vertical bare bulbs. I should have stated this in the OP, my apologies. With 400W bare bulbs on light movers do you think 9" of separation between light and canopy is efficient? Can it be moved closer without risking burning the plants? I want to make sure I am getting as many lumens to reach the plant as possible with minimal waste and minimal light burn.

I have heard about a mini split system from a few people now but don't have the budget to go out and get one this go around. Possibly next round if the numbers work out. I'd love to hear the pros and cons of a mini split, especially if you have used a different system before switching to that. Comparisons are always nice.



As always any feedback is more than appreciated