Ventilation Question

Hello,

This is my first time growing and I bought a grow tent that I have indoors in an outside shed. I tried growing a couple plants and they seemed to be struggling due to not having enough fresh air. I have a box A/C unit in the shed since I live in a typically hot climate (though we do have some cold winter temps), but it didn't seem to provide enough oxygen on its own. I had all my passive intakes closed which may have been the problem, but I'd like to introduce an active system before I give it another go.

So first I'd like to know if I need to drill a hole in the shed wall to add my ducting for the intake fan, or if it's recommended to just have the intake fan pull from inside the grow room. I figure it would be best to pull from outside to get as much oxygen as possible & since I don't want to constantly be opening the doors and windows on the shed to keep it as stealth as possible.

Second question is about my exhaust fan. I have my exhaust fan connected to a carbon filter which I have just laying next to my tent inside & now that I think about it, it's probably working against my A/C unit. So, should I add another hole in the wall of the shed leading outside to vent the hot air out as well?

Are you going to have the ventilation & AC hooked up to thermostats to flip between them running (i.e. fans off/AC on & vice verse) or were you planning to run them all the time? That'd be expensive as all the cold air will be sucked out.

If I was in your place I'd probably run an air cooled hood to vent the heat from the bulb outside (ideally keep the ballast outside as well), then the AC won't be working as hard & add some CO2 (either a proper system or home brew) to keep them happy. Is it humid as well or just hot?

Somatek said:

Are you going to have the ventilation & AC hooked up to thermostats to flip between them running (i.e. fans off/AC on & vice verse) or were you planning to run them all the time? That'd be expensive as all the cold air will be sucked out.

If I was in your place I'd probably run an air cooled hood to vent the heat from the bulb outside (ideally keep the ballast outside as well), then the AC won't be working as hard & add some CO2 (either a proper system or home brew) to keep them happy. Is it humid as well or just hot?

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I actually am using LED's that don't produce a lot of heat so I don't think we will need the air cooled hood venting. And yes it is humid as hell, but I have a dehumidifier that I think will keep it in line. The heat is controllable in the shed and the A/C is on a thermostat. So should I be bringing the fresh air in from the air conditioned shed or from an exterior hole in the wall bringing fresh air from outside?

If you're running ac & a dehumidifier adding CO2 and running a sealed room is more effective then vent air. I'd look at adding a CO2 system, it'll cut down on the cooling/dehumidifying.

Somatek said:

If you're running ac & a dehumidifier adding CO2 and running a sealed room is more effective then vent air. I'd look at adding a CO2 system, it'll cut down on the cooling/dehumidifying.

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Being his first go around his focus on failing everything in. Before adding co2.

Have your extraction and filter in tent venting to outside with ducting, make sure your intake is less powerful, I e 5 inch extraction- 4 inch intake etc. Oscillating fan will help move air about. Yes, put intake from the outside pulling directly into your tent to the bottom, have your tent holes open a bit to relieve any pressure and create some more air movement/ circulation. I wouldn't bother with co2 like above poster said, besides imo it doesn't make such a huge difference, especially running high wattage hps. Maybe in led , but it's not that great tbh, tried it a few times and apart from the ability to handle slightly higher temps it was more work and effort/ money etc than the benefits.

Lordhooha said:

Being his first go around his focus on failing everything in. Before adding co2.

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Did you mean "dialing" rather than "failing" ?

tiltswitch said:

Have your extraction and filter in tent venting to outside with ducting, make sure your intake is less powerful, I e 5 inch extraction- 4 inch intake etc. Oscillating fan will help move air about. Yes, put intake from the outside pulling directly into your tent to the bottom, have your tent holes open a bit to relieve any pressure and create some more air movement/ circulation. I wouldn't bother with co2 like above poster said, besides imo it doesn't make such a huge difference, especially running high wattage hps. Maybe in led , but it's not that great tbh, tried it a few times and apart from the ability to handle slightly higher temps it was more work and effort/ money etc than the benefits.

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Okay this sounds like what I will do. But I have a pretty small grow tent so space is pretty crucial; so is there any spot other than inside the tent to position the carbon filter?

Now, I was a bit confused where the actual fan for the intake is supposed to be positioned. I was thinking on the top left side of the tent (as the extraction fan is inside the top right side) but I couldn't figure out how to duct that to the bottom.

shroomysam said:

Did you mean "dialing" rather than "failing" ?

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Yes damn autocorrect.

shroomysam said:

Okay this sounds like what I will do. But I have a pretty small grow tent so space is pretty crucial; so is there any spot other than inside the tent to position the carbon filter?

Now, I was a bit confused where the actual fan for the intake is supposed to be positioned. I was thinking on the top left side of the tent (as the extraction fan is inside the top right side) but I couldn't figure out how to duct that to the bottom.

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Generally you can run the intake passively. Create a negative pressure inside that tent and it’ll draw in plenty of air. The carbon filter needs to be inside of the tent to properly filter the air and create that negative pressure. How many plants do you plan on running?

Lordhooha said:

Generally you can run the intake passively. Create a negative pressure inside that tent and it’ll draw in plenty of air. The carbon filter needs to be inside of the tent to properly filter the air and create that negative pressure. How many plants do you plan on running?

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You think I'll be good if I just use the passive intakes? Cause I feel like bringing air from outside is gonna fuck up the climate in my shed.

I have the carbon filter right outside my tent on the ground, connected to my ducting that runs from my exhaust fan, is that not okay?

Was gonna try to flower about 4 - 6 plants. Wouldn't mind adding Co2 tank to the shed later on down the road if needed, but I'd like to get a grow or two in first to get the hang of things. Maybe I could just crack a window...

shroomysam said:

You think I'll be good if I just use the passive intakes? Cause I feel like bringing air from outside is gonna fuck up the climate in my shed.

I have the carbon filter right outside my tent on the ground, connected to my ducting that runs from my exhaust fan, is that not okay?

Was gonna try to flower about 4 - 6 plants. Wouldn't mind adding Co2 tank to the shed later on down the road if needed, but I'd like to get a grow or two in first to get the hang of things. Maybe I could just crack a window...

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You want to pull air through the filter not push air. The shed isn't sealed I'm sure even with slight cracks there will be air exchanged. So outside air will get in either way. Passive should be good.

Also if you are planning on running co2 you need to ensure its fully sealed. I axed my co2 it wasn't really worth it to me.

Okay ya you're right, even when it's closed its definitely not air tight. Okay we will open the passive filters! Thank you so much man.

What is axed?

shroomysam said:

Okay ya you're right, even when it's closed its definitely not air tight. Okay we will open the passive filters! Thank you so much man.

What is axed?

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Axed as in cancelled, shut down, and all that.

Lordhooha said:

Axed as in cancelled, shut down, and all that.

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Ahh, you think if I introduced more plants (another tent for flower & another for mothers) I would need to add Co2 or is it pretty much useless all-together?

Keep in mind that when you start your 12/12 flowering cycle, those vents at the bottom of the tent are going to let in a lot of light, unless you lightproof your shed. They're great for veg, but when it comes time to flower, depending on the amount of light coming in, it can cause a lot of problems. I added an active intake to deal with this.

Just put short pieces of duct in the holes. Passive will work fine. Rig your filter at the top if you have not alot of space.you won't need c02 Iv got up to 150 plants in one room and still don't need to use it , there's plenty of c02 in the air , you can only push a plant so far anyway.

shroomysam said:

Ahh, you think if I introduced more plants (another tent for flower & another for mothers) I would need to add Co2 or is it pretty much useless all-together?

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Qjs is right too in that shed if there are windows you should really block them off. Also for the co2 I find there's plenty of it in the air. Plus it's a waste of your not full sealed up for the most part anyway. Co2 has its place whether its tanks or burners however it just didn't make sense for me in my rooms. I do fine without it.

gjs4786 said:

Keep in mind that when you start your 12/12 flowering cycle, those vents at the bottom of the tent are going to let in a lot of light, unless you lightproof your shed. They're great for veg, but when it comes time to flower, depending on the amount of light coming in, it can cause a lot of problems. I added an active intake to deal with this.

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tiltswitch said:

Just put short pieces of duct in the holes. Passive will work fine. Rig your filter at the top if you have not alot of space.you won't need c02 Iv got up to 150 plants in one room and still don't need to use it , there's plenty of c02 in the air , you can only push a plant so far anyway.

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Lordhooha said:

Qjs is right too in that shed if there are windows you should really block them off. Also for the co2 I find there's plenty of it in the air. Plus it's a waste of your not full sealed up for the most part anyway. Co2 has its place whether its tanks or burners however it just didn't make sense for me in my rooms. I do fine without it.

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Yeah my shed has a couple windows but I've already blocked em. Couldn't I just make sure during flowering that the timer is just set to turn the lights off at night time so it'll b dark anyways? Only thing I can think of is if I eventually add a separate tent for flower to make it perpetual, I guess I could add an active intake to the flower tent then... hmm