I have a louvered vent window close to the ground in one wall of my small greenhouse. It's become an entrance point for mice and shrews during the winter and for chipmunks once the weather turns warmer. I can set traps for the mice and shrews but the chipmunks - not so much. I had to remove plants under lights on a lower shelf because the chipmunks were coming in to sample the "salad buffet". Any ideas/plans for constructing a screen to place on the outside of the GH wall?

How about extending the shade cloth to the base of the greenhouse, Cindy? I guess critters could eat right through that cloth so in that case you could surround the base, perhaps a foot up depending on the size of the vent-window, with thick, small mesh chicken wire or similar wire mesh.

Thanks for the suggestions! I don't use shade cloth in the GH until late spring/early summer as I'm trying to get as much light in there after a dreary, cloudy winter. I did have a chipmunk earlier this spring dig from the outside, under a 6x6 composite timber and up through the gravel in the GH. First time ever. I was thinking of constructing some type of frame to cover with 1/4" hardware cloth that would fit tight over the window on the outside and just leave it up year-round.

You could put down either #2 or #3 mesh hardware cloth on the subfloor (ground?) so that nothing could tunnel in from the outside. And the same could be used over any vents that the critters are getting through.

I can definitely lay down some mesh under the gravel on the inside (once the GH is empty for the summer) but constructing a frame for the louver has me stumped.

You could build a frame out of 1/2x1" or 1x1" wood or some type of plastic molding, all of which should be found at a Lowe's or Home Depot.

Thanks for the material suggestions!

If you are still looking for possible solutions to stop critters from getting in through the louvers you might consider expanded metal. Lowes & Home Depot have it, usually with glass & plexiglas - near where they sell doors. It has a diamond pattern made by a machine that makes slits in sheet aluminum then "stretching" the plate to open the slits into a diamond shape. This stuff is often used to protect screen in screen doors from being pushed out of the frame. (Heavier gauge steel is sometimes used in BBQ grilles to hold the charcoal).
Anyway, making a wooden frame to go around the louver then mounting this to the opening should deter the critters (be sure the frame stands out far enough so the louvers open). If screening is used to keep bugs out I would suggest it go on the inside the of the expanded metal for protection.



I have used this material on other projects to deter squirrels and it works very well. Once I build my GH in a couple months I hope to do the same thing, except perhaps using aluminum angle rather than wood. I am considering doing the same thing for the roof vent.

We put hardware cloth under the floor of our greenhouse, and also screened all the vents with it. We had mice coming in constantly and it has solved the problem. Haven't found any more, or had any more produce eaten.

Excellent Karen!
Squirrels are my main concern. I know possums come around occasionally but haven't ever had problems with them messing anything up (well there was that one night one startled me on the back deck; only thing almost messed up was my pants - that's when I learned they have no problem living in the middle of town). I'm going to protect the opening because of possible snakes (see parenthesis above except remove the word "almost"); they are non poisonous but I hate surprises.

I'm looking at Palram; their louver is only near ground level - wish it could mount higher but for ventilation I suppose the ground is the better place.

I used to have ground squirrels coming in my lower vents. I do have a louvered vent up midway with a solar fan mounted in it. It works well. It came from Growing Spaces.

Our solution - DH made a box frame out of 6" aluminum fascia and we covered with 1/4" hardware cloth. Bent a flange on the box frame and screwed it to the louvered window frame. Enough clearance around the window louvers so that they are operational. I remove the pneumatic operator in the winter and removed the glass louvers. I stuffed the box frame with insulation for the winter. Works perfectly.