Greenhouse humidity

Hi all

I currently have a couple of autos in a greenhouse at around 10 days or so. All is well but have a quick question about the humidity.
Humidity can range from 55% to 70% and I have recently installed a small oscillating fan and when this is on, humidity rises around the 80%+ mark. I was under the impression humidity would be lowered when the fan is on or is this because I’m growing in a greenhouse with no vents except the door? This is not causing any problems as of yet but I think I might have issues towards the business end of the grow.
Thanks

A circulation fan will not remove humid air, it will simply move it around

An exhaust fan would be a better option to introduce fresh air

Thanks for the reply. That makes sense but would it also raise humidity as every time I check before and after the fan is on it always drops temps and raises humidity. I’m using a polythene greenhouse so was thinking to make my own vent top and bottom to air can escape.
thanks

Greenhouse Autos said:

Thanks for the reply. That makes sense but would it also raise humidity as every time I check before and after the fan is on it always drops temps and raises humidity. I’m using a polythene greenhouse so was thinking to make my own vent top and bottom to air can escape.
thanks

Click to expand...

Roll the sides up or open the ends if you can.

Was thinking maybe leave one zip on the door half open and lift plastic up towards the bottom and see how that’s goes

Billy the Mountain said:

A circulation fan will not remove humid air, it will simply move it around

An exhaust fan would be a better option to introduce fresh air

Click to expand...

To add on to this, an exhaust fan will introduce outdoor air into your space which is nice however the humidity will be whatever the humidity of the outdoor air is that you're introducing - so it's great if your outdoor air humidity is lower than the your space humidity and you're trying to dehumidify, but if it's raining out (100% rh), introducing that outdoor air into your greenhouse isn't going to do anything for humidity and will probably increase it if anything.