Do I need exhaust fan? Roof vent entire length of roof.

[tropterrarium]

I have a mini GH 9'Wx4'L. There is a roof vent over the entire 4' length of the roof, with a automatic solar opener. There is plenty of air circulation in the GH and I am putting a swamp cooler in there. There is a bottom side vent as well.

Question: do I need an extractor fan? Given that the roof vent is running the entire length, it is impossible for heat pockets to accumulate under the roof, and the fans provide plenty of circulation so stratification should also be eliminated. Do I miss something?

[dounoharm]

you might need a shade cloth.....otherwise it sounds like a good plan...experiment with a few house plants in there and use a max/min thermometer to tell you the temp range....before you entrust your orchids to it tho....gl

[camille1585]

I think you would only need an exhaust fan if you were having trouble keeping the temperature low enough in the summer. If this is a new GH, I guess you'll only know if the set up is fine once you've experienced summer. And I agree about being careful about what plants go in there until you know everything works fine.

[tropterrarium]

Thanks for the quick replies. The GH is in a shady spot, and I am growing shady species in there lots of pleurothallid alliance, plus some others. So no need for shade cloth. Yesterday we had an unseasonably hot day going into the mid 90's, and the GH had a top temperature of 81, mostly stayed below 80 though. I have analog and digital thermometer and hygrometer in there, so have a pretty good idea of what the conditions are during the day.

I did already move in the orchids. House plant "canaries" possibly would be ideal, but don't want to just have a geranium sitting in the new GH for a year to check the cycle. My patience has its limits. So far so good.

thanks again.