Ventilation help

[420Yooper73]

Hi guys. I’m going to add a ventilation system to my grow room for my winter grow. I’m having trouble figuring out what size fans I need and how often to run them. My grow room is 15x14x8. Some things I read say they need to ventilate every 3 minutes! How the heck can you maintain temperature and CO2 levels..I’m going to be using a CO2 generator as well. Any info would be great. Thank you

 

[bobrown14]

So bedroom size grow - how many plants you growing?

Some folks will use 2 or 3 tall filter cans with 6 or 8" blower. Really depends on plant count when you get that large of a space.

 

[420Yooper73]

So bedroom size grow - how many plants you growing?

Some folks will use 2 or 3 tall filter cans with 6 or 8" blower. Really depends on plant count when you get that large of a space.

I just finished a grow of 12 plants in there..I got away with just regular fans and a window and door open because of the summer weather but winters get cold up here so I’m going to have to add active ventilation

 

[bobrown14]

12 plants - 6" blower with a filter is enough. Can just leave the filter in the room too so you keep things warm just monitor rH. Winter time I don't ventilate outside I just clean the air so my house doesn't reek like weed.

 

[420Yooper73]

12 plants - 6" blower with a filter is enough. Can just leave the filter in the room too so you keep things warm just monitor rH. Winter time I don't ventilate outside I just clean the air so my house doesn't reek like weed.

Awesome. Thank you. That sounds like a great idea. How often do you run your fan?

 

[bobrown14]

I have several fans going. Big ones blowing on the plants 24/7 and smaller clip fans blowing on the lights above canopy at lights on.

 

[420Yooper73]

I have several fans going. Big ones blowing on the plants 24/7 and smaller clip fans blowing on the lights above canopy at lights on.

I mean, does your blower run all the time or does it cycle on and off?

 

[Elvin]

I just finished a grow of 12 plants in there..I got away with just regular fans and a window and door open because of the summer weather but winters get cold up here so I’m going to have to add active ventilation

I grow in a finished attic which is not heated other than through convection (heat rises from the first floor) so what I do is use my flexible ductwork to draw warm air. I will either drop it down to the bottom of the stairs (mostly) or when it's extremely cold I have a hole in the floor that was used to allow the living rooms heat to rise into the attic. I just drop the hose through that.
A whole room has two options to get heat into it; heater or moving it from another location. An oil-filled electric heater will work well and you won't have to give it much space compared to one with a fan.
You could do as I do, run the intake duct of your ventilation fan to a warm area to suck up warm air and run it 24/7.

 

[labexperiment]

If you are running CO2 you should be recirculating the air rather then replacing it. You would typically replace the air if not running CO2, because the plants breathe CO2. With CO2 you also have to run your heater, AC, humidifier and de-humidifier in the room to maintain proper RH and temperature.

 

[420Yooper73]

If you are running CO2 you should be recirculating the air rather then replacing it. You would typically replace the air if not running CO2, because the plants breathe CO2. With CO2 you also have to run your heater, AC, humidifier and de-humidifier in the room to maintain proper RH and temperature.

Thank you. Your info really helped a lot.

 

[TurboBucket]

If your running co2 keep that baby sealed up, run your blower 24/7. Circulate the air from end to end with the blower and filter. Air movement is a huge component of fighting off mold/bud rot. Use multiple oscillating fans to keep the air well mixed and prevent moisture from accumulating on the leaf surfaces.
You'll definitely want a dehumidifier in there to extract all the water your plants breathe out.

You may or may not have a problem with high temps depending on how well sealed/insulated the space is. But with Co2 they can get quite hot with no problems.
A make up air setup for the intake would be ideal. Tap into the return portion of your duct between the filter and blower with a smaller run that goes outside. This will pull cold outside air in and mix it with the warm air already being circulated before it contacts the plants. You can use a 24v controlled damper with a thermostat so it only opens when needed. Much cheaper than AC.

 

[420Yooper73]

If your running co2 keep that baby sealed up, run your blower 24/7. Circulate the air from end to end with the blower and filter. Air movement is a huge component of fighting off mold/bud rot. Use multiple oscillating fans to keep the air well mixed and prevent moisture from accumulating on the leaf surfaces.
You'll definitely want a dehumidifier in there to extract all the water your plants breathe out.

You may or may not have a problem with high temps depending on how well sealed/insulated the space is. But with Co2 they can get quite hot with no problems.
A make up air setup for the intake would be ideal. Tap into the return portion of your duct between the filter and blower with a smaller run that goes outside. This will pull cold outside air in and mix it with the warm air already being circulated before it contacts the plants. You can use a 24v controlled damper with a thermostat so it only opens when needed. Much cheaper than AC.

That is awesome information. Thank you for the tips. I currently run a dehumidifier and three oscillating fans. I use LED lighting, so a lot of excess heat hasn’t been an issue so far. I especially like the idea of taping into the return line to help warm the cold winter air we get up here in the Upper Peninsula of Michigan. Thanks again, I really appreciate your advice. Happy Growing

 

[TurboBucket]

Feel free to stop by the Michigan growers roll call thread in my signature

 

[420Yooper73]

Feel free to stop by the Michigan growers roll call thread in my signature

Awesome, thank you