Re-designing urban grow room - To Seal or not to seal?

Hey guys
I've done three grows. One DWC in a 4x4 tent, one Coco Coir under Mars Hydro 1200, and most recently two Mars Hydro 1200 over Current Culture 6 bucket, 8gal "XL" RDWC setup in a 7x10 room.

For cooling, I'll be scrapping the single exhaust LG 8000BTU portable AC I've been using for a dual hose, hopefully 14000 BTU portable unit.
Also have one 6" inline fan, 6" carbon scrubber, 6" duct booster fan and 4" duct booster fan.

Unfortunately I'm stuck with the portable AC units as the room has no window, and the nearest is about 12' away. Mini split isn't an option due to building restrictions.

The actual grow room total size is 10x10 with 8ish foot ceilings.


So! Does it make sense to seal the room off and run c02 from 20lb tanks?
I can't get larger tanks as I've got 3 floors of steps to climb, and a burner isn't possible.

I'm thinking to hook up 14k dual inlet AC with the 4" booster feeding the inlet, and 6" booster helping the exhaust out. I will get insulated ducting to cover the 12-15' run to the window from the room.

Thinking to purchase an Ioponic grow controller so I can monitor and control everything while I"m not home/at work from my phone..

With that, I should be able to run 600-1200ppm c02 up to 85 degrees, and have the AC kick in to keep below 85, or when flowering down to 70, correct?

Will I need anything besides Ioponic controller and c02 tank to get Co2 going? Also, can I run the Mars Hydro lights daisy chained right off the controller, or will I need some kind of relay?

Thanks!!
S

The portable ac units generally are quite in efficient, and in my experience usually suck co2 out of the room.... Even building an actually sealed back on a more efficient widow ac and venting that... But really mini split or maybe a water cooled ac would be ideal... My water cooled was more efficient than my split units if I recall correct.

AC/co2 will up a yeil quite a bit under ideal conditions, and my best crops with co2 beat my best. With out by 1/4lbs per bulb.... But if not ideal can actually rob yield through fluxuating conditions. Anyways good luck, n just try to focus on ideal conditions in the room what ever the system, and lots of fail safes in event of failure....

Will restrictions and whatever allow you to cut a hole in the wall? You can use a thru the wall AC which would be far better than a portable. More efficient and placement could be much better. If you're stuck with a portable, I would use the least amount of flex duct possible. Use straight metal duct. You can insulate it yourself. On a long run like that, the resistance will be way less with straight duct pipe. Cheaper too. Good luck. -granger

Thanks for the response guys

Granger- the room is about 15' from an outside wall, and that wall is brick. Can't cut any holes in the brick unfortunately.

I do have mostly straight hard duct thru the 15' which goes back to flex to manage getting out the window. Does make sense to just insulate that. Would I really only need to do the exhaust side and leave the inlet as is?

Attached crude photo for ref

Seems that you shouldn't need to insulate the intake side. Good luck. -granger

Still needs booster tho, right? Does it matter where in the chain it goes?

How do those Mars hydros work for you. I was thinking of of picking up a couple for veg.

I haven't owned any other light to compare, so take everything with a grain of salt.

Pros: My first grow was White Widow in 5 gal DWC buckets in a 4x4 tent. Outside of reading some posts and Jorge C's book, I had no prior experience or even knew anyone personally who grew. The plants were literally put through everything, from the roots growing together/subsequently needed scissors to cut them apart, heat issues, on and on... and I still pulled just short of a full P in 130 days (ending in 25gal DWC) on one light. The bud was very, very nice looking although not crazy potent. Also got beans from an unknown source.

The second run was kinda half-assed through summer with way to small Coco Coir/fabric pots (Blueberry, Snow Bud) and the yeild was much smaller (probably 2oz max) but the quality and potency were significantly nicer, although the bud structure wasn't quite as nice as the original White Widow. a little fluffier) Dinafem/Freebie seeds.

Third grow was 6 plants (Two Power Plant, one Night Queen and one Jack Herrer) in six (8) Gal Current Culture RDWC pots. I expanded the grow size to a 7x9 table and added the second Mars 1200. Admittedly the seedling to veg intro stage was pretty shit. I started in solo cups in the window sill and the seedlings had it rough for 2 weeks or so)
The little single hose 8k BTU portable AC I had could not keep up, and I blew it a little in terms of exhausting too much air continuously thus making it even harder on the AC, so heat was an issue. The Night Queen is one of my favorite smelling strains Ive ever had, and smoked great. The Power Plant herm'd a little and had decent yeild but tasted eh, and the Jack H was somewhere in the middle. I honestly forget where the beans came from, but the Jack H was a freebie.

The lights def put off some heat, but the bottom of them isnt TOO hot to touch (certainly not COOL to the touch, but ive brushed my elbow over it and only felt mildly uncomfortable - ha) My original 1200 doesn't have it, but the new edition has the FLower/Veg switches which came in handy when heat became a real issue. I saved a couple degrees by shutting the veg lights off when it started warming up in the building as a whole)

The lights seem to really be pretty great for Veg, lots of nodes formed on all strains/all grows and I never semed to really stunt the growth from regular pruning (which could be a nod to the RDWC) As far as flower, if this new setup allows, I'll add a 600w Gavita to the center to try and put some weight on the buds, but the 1200s seem pretty legit for flower as well)

The one bummer is inability to ramp up/down the intensity. I'd really like to have a 15 or 20min "warm up period" for the plants, which I will probably do with a 200w CFL on a timer to come on 20min earlier if I can't get a Gavita in there.

I think with a chiller/better control over the temps and some kind of c02 setup I could come close to a g/watt with these lights though.

hope that helps!

stupid question - is it cold where you live? why not punt the CO2 and just vent outside. I was able to run 1000w in tents in a bedroom here through June with the windows open. Did not even use active ventilation, just left the windows and door open. I shut down for the 3 hottest months and start up again in Sept. But I live pretty far north.

Will the benefits of C02 in a 2-lamp grow be worth the A/C cost to seal it?

thats a good point. When it comes to cost, anything I do in this room is basically an early investment to a larger setup I'll get going once I've got bigger space to work with. Hoping this is the last winter I've got to grow in this one.

It'll get cold in the winter outside, but we're on the top floor and dont have control over building heat. We'll keep a window open to prevent it from getting crazy hot in here, but with the grow room being sort of poorly insulated it ends up heating up the rest of the apartment too. It might be 15 degrees out at night, but we're sweating our dingus's off in here. it's a tough spot.

With that said, I really should consider improving the vented setup too. good looks

My advice

My advice

You can't go wrong with a mini split and co2. A cheap pioneer unit will get you a few years of service even with a self install, you will need a vacuum pump. If you live in a place where you can get one installed for a reasonable rate with a warranty, go that route. First I would spend the money on replacing the lights. I have had 5 Mars lights, a 1600, 1200 and 3 400. The buds will look good but production will be less, they veg well but not as good as a t5 or especially the cmh. Cob LEDs, air cooled double ended or even cmh 315s for flower are your best bets. Use the Mars for veg and try others to compare so you can see for yourself. I am not trying to dictate anything but I have been where you are. If you are putting in the time reach the maximum potential. The goal is 2 lbs per 5x5 and with the right plant, co2 and ideal temp, humidity and nutes you can double that.

Can't run a mini split

I missed that

I missed that

The dual hose will still exhaust your co2. If there is no way to use a mini split I would skip co2 and vent the area the biggest quiestest way you can. Get a different light, a 315cmh, a 3590 cob, or any hps and do a side by side just to see for yourself. Best of luck.

ah really? great info. thank you for that -


Is there a way to calculate the CFM I need to vent for the room? 7x10room, with the Mars Hydro LED's drawing roughly 1100watts from the wall, plus about 300 watts for air pumps/water pumps and humidity control..

Would a 720CFM 8" inline fan be sufficient?

also, if an 8" fan was sufficient, I'd need a 16" hole in the wall for intake? Trying to read up on this more, but for the sake of multiple opinions, i'm also curious to ask here.

The ambient temp of our place is usually between 70 and 78 in the winter... building controls the heat, so we have to keep a window cracked to keep it from getting any hotter then that

Read the Ventilation 101 Sticky. Good luck. -granger

Dual hose portable ac units won't exhaust your co2. But they are very inneficient so keep that in mind

Have you had good luck using a dual hose?

Have you had good luck using a dual hose?

I could watch my co2 meter drop when the dual hose kicked on and have friends with similar experiences and have read countless others, but maybe there are some brands that work.
Doing two 8" holes or 1 16" for passive intake would work well with a 8" exhaust fan on a speed controller or a thermostat. Exhaust high intakes low. It's a little expensive$110 but the autopilot co2 logging meter is nice to have a record of things like temp, humidity, and co2 if a problem arises.

Sorry,i didn't read all that above, all good info but... its not easy to 'seal' a tent. think zippers and sewing holes.. but you might get close to sealed, kinda like almost pregnant.. EDIT: I still have all the shit on the shelf..