I’m almost all set up to start growing but I would like to during the day when it’s hotter outside have fresh air come into the tent from within the house and at night have fresh air come into the tent from outside. Is this a good ideal? if so should I use a filter? what filter would you recommend that’s cheap? Thanks
I think what you’re describing is a good idea. While I don’t grow in a tent, I do have an intake port outside my closet that runs inside and allows air to be pulled in from the outside via the outtake fan and a small fan. Regarding a filter, I use a section of window screen attached to the outside opening of the PVC pipe that is just outside the closet. It’s not a very sophisticated filter, but it does trap dust, hair, and other debris. I clean it regularly. By the way, you don’t want a filter that’s going to be too restrictive of the fan(s) pulling air in. This could cause your intake fan to run hot and potentially shorten the life of the motor.
I assume this means first grow? If not I apologize. I think you may be thinking too much into it. If the tent is inside, and you don’t die from the air quality, the plants should be fine 
I would spend more time worrying about where the heat/smell will be vented to. IMHO.
edited: also, introducing outside air also introduces many bad options you would have to filter for, which would raise the cost and hassle.
Personally, and to make things simpler, I would bring all the air from a clean area from inside the house. This will help reduce pests and other nasties that’ll hurt your girls. As for filters, I’ve just used regular air filters you can get at home depot or lowes that fit into ductwork, even had a buddy use a washable car intake filter (the kind you can find at autozone) to filter his air.
But if you want to use a filter for horticulture, I would recommend a Dust Shroom Filter and throw that on your intake.
I have purpose built grow and flower rooms. The air intake system I use is exactly what you are describing @weedify. I mostly leave the outside intake off in the summer because it’s too humid at night where I’m at. I do like the outside air once it cools off though and it’s way cheaper than AC
1 Like
Definitely use a filter when pulling air in from outside
A pleated filter is the best fir a cheap filter
They should run 3-5 $ ea
At hardware store
The blue or white fiberglass filters dont work well and let small dust and pollen etc pass right threw
2 Likes
I agree with @Countryboyjvd1971, anything with a HIPA rating would be good. Look for 'allergy prevention" or something like that.
Imagine finding out that your idiot neighbor ended up with a male, and just set it outside to get some seeds…
1 Like
OK and just cut the filter so it fits?
1 Like
Yeah see if you can find a 12x12 or something thats is close to the size opening if its a pipe sticking out you can bend and tape it over the end just make sure you blocking intake 100% with filter and stay on top of it change when dirty
1 Like