Ventilation

Green house ventilation ...
I bought a second hand EDEN 8’ x 12’ ... just assembled it on weekend.
Couple of questions on ventilation ....
It has 2 x 24” square window vents, and that was all the previous owner had in place.
I also have the Louvre vent, which has never been fitted .... (but no glass)

Is it worth fitting a Louvre vent ? .... I guess if I do, it would not make any difference whether fitted on rear or side ?

Secondly is it worth buying the automatic window openers ? .... and if so, anybody got a view on which ones ....
Greenhouse Spares Autovents at Gardencraft, Porthmadog, Gwynedd, North Wales

They range from £18 to £40 ... all fit same size windows ... so are the more expensive spring ones better ?

Do I need to fit one on each window ? (not intending to fit to Louvre)

 

I think the Louvre is useful. I would put it on the back wall, unless that faces the prevailing wind, in which case I would put it at the back, but on the side most away from the prevailing wind.

Greenhouse cooling works best by convection, rather than "draught". The Louvre will make that work well, next up when the greenhouse gets too hot is to open the door, but I think that stresses the plants more because of the volume of air that moves past them ... that in turn means they transpire more water.

If you will always be around to open & close the vents (and not forget!) or you have a neighbour who would be reliable, then manually opening them may be better - when its not particularly hot I open the ones away from the wind).

I also like to leave some of my vents open a crack during summer nights - automatic vents will shut right down (although you could probably put a small piece of wood as a jamb to stop them shutting completely

But for unattended ventilation they are pretty much a "must"

Yes you will need openers for each window - to cool your greenhouse they are going to have to be fully open on hot days - and the door open too.