Grow Room too strong ventilation system?
- Thread starter Sami
- Start date
I'm very interested to know the same! Hope some experts gonna chime in on this one!
For lack of any expert help.......
Basically if the air outside your tent is the proper temp & humidity then let it flow (of course not tropical storm wind conditions).
If you have to create the proper conditions inside your tent (temp & humidity) a heavy air flow would push all that proper environment right out of your tent only to have to try to condition the fresh air coming in which of course it can't because it's being sucked right out again.
Basically if the air outside your tent is the proper temp & humidity then let it flow (of course not tropical storm wind conditions).
If you have to create the proper conditions inside your tent (temp & humidity) a heavy air flow would push all that proper environment right out of your tent only to have to try to condition the fresh air coming in which of course it can't because it's being sucked right out again.
- Joined
- Jun 3, 2017
- Messages
- 5,343
- Reputation
- 415
- Reaction score
- 14,151
- Points
- 0
- Currently Smoking
- personal F1
Too strong? We are talking extraction here, correct? If so, I expect there is a point of diminishing return, but I don't know about detrimental. Once under negative pressure, the limiting factor becomes the size of your intake. And there's no reason to go above what's needed to keep the air fresh.
Now if talking about air movement around inside the area, then yes. Visible movement throughout canopy is plenty. Gail force turbo fans not recommended.
I guess at some point, too large a fan, run too high would start to strain the tent stitching over time, but that'd be way overdoing it.
Now if talking about air movement around inside the area, then yes. Visible movement throughout canopy is plenty. Gail force turbo fans not recommended.
I guess at some point, too large a fan, run too high would start to strain the tent stitching over time, but that'd be way overdoing it.
You want your extraction strong enough to suck the sides of your tent in. You also want your fan motor to be sized correctly, meaning that it can run at say 30% power continuously. That would be your low idle on your fan speed. If your fan is too strong you won't be able to run at 30% and keep the temperature inside your tent proper. So yes, when you get too strong of a fan it will cause of environmental problems.
You need to think of extraction in the terms of moderating air temperature and humidity in your tent.
You need to think of extraction in the terms of moderating air temperature and humidity in your tent.
- Joined
- Oct 19, 2019
- Messages
- 7,437
- Reputation
- 7,491
- Reaction score
- 37,448
- Points
- 0
- Currently Smoking
- Various strains, via various intake tools, but no combustion.
Bottom line is that you are trying to maintain the correct combination of temperature and humidity inside your tent, ideally to within the range suggested by VPD charts (for example, have a look at https://www.alchimiaweb.com/blogen/vapor-pressure-deficit-cannabis-cultivation/) .
Whether you need more air exchange (i.e. higher fan speed and/or less restricted air intake opening) or less will depend on the temperature and humidity in the room in which the tent is sitting, how much heat your grow lights generate, and the growth stage of your plants. The more air exchange, the more similar the air in the tent will be to the air outside it. The less air exchange, the hotter the air inside the tent will be because of the heat from the grow lights. The response of relative humidity is more complicated. On one hand, less air exchange tends to raise temperature which, without other changes, would reduce relative humidity. However, less air exchange also means that the moisture released by the plants is removed less effectively, pushing relative humidity in the opposite direction. The larger the plants, the more the moisture released can dominate.
What I try to do is minimize the air exchange (the plants do not need a complete turnover every few minutes, just a steady small input of fresh air), while keeping the temperature and humidity within limits suggested by the VPD charts. In my setup, I could not do this without both a fan control and a humidity/temperature gauge inside the tent.
As others mentioned, a fan to move air around in the tent is a good idea. Not a blast directly on the plants, but enough indirect air movement to gently agitate the leaves.
Good luck with your grow.
Whether you need more air exchange (i.e. higher fan speed and/or less restricted air intake opening) or less will depend on the temperature and humidity in the room in which the tent is sitting, how much heat your grow lights generate, and the growth stage of your plants. The more air exchange, the more similar the air in the tent will be to the air outside it. The less air exchange, the hotter the air inside the tent will be because of the heat from the grow lights. The response of relative humidity is more complicated. On one hand, less air exchange tends to raise temperature which, without other changes, would reduce relative humidity. However, less air exchange also means that the moisture released by the plants is removed less effectively, pushing relative humidity in the opposite direction. The larger the plants, the more the moisture released can dominate.
What I try to do is minimize the air exchange (the plants do not need a complete turnover every few minutes, just a steady small input of fresh air), while keeping the temperature and humidity within limits suggested by the VPD charts. In my setup, I could not do this without both a fan control and a humidity/temperature gauge inside the tent.
As others mentioned, a fan to move air around in the tent is a good idea. Not a blast directly on the plants, but enough indirect air movement to gently agitate the leaves.
Good luck with your grow.
Last edited:
Yes agreed, unless the air you are pulling into the tent is the same or higher temperature than air in tent.
Similar threads
