Well, in the interest of complete disclosure, here's a link to an older thread that has a photo (over half way down) of orchids hanging from the frame of a Harbor Freight greenhouse:
Two HFGH 10x12 Greenhouses Joined Together

She used the clips on this page (normally used to secure bubblewrap.)
www.littlegreenhouse.com

However, I have also been way too chicken to hang weight from my own HFGH frame. I just don't want to take the chance of adding more stress to the structure. I am not brave. But I have to admit, when I look at Funnylady's wonderful photos, it makes me jealous.

I finally talked myself out of hanging plants, but I always intended to build a wooden upright frame to hang them from. We built wooden benches that are anchored into the ground, so my plan was to add uprights and a sturdy horizontal beam. (Think goalpost shape.) This way the weight would be handled by my benches, and the GH structure would remain untouched. Just a thought.

We added a fan to our greenhouse, from ACF Greenhouses, and this part of my blog shows how we did that. It also includes links to the sites where we bought the fan, and thermostats to run the fan (and our heaters, in winter.)
Part Seven, Greenhouse Enhancements

I never used auto vent openers, but you can use the search archive here to turn up more recommendations. From my reading, the vent openers sold by Harbor Freight don't get many good reviews. Some folks say they don't last long and are not a good investment. Brands like Bayliss and Univent seem to get better reviews. Hope this helps a bit.

Use shepherd hooks

Sorry Mudhouse that I didn't response sooner but I want to thank you for your blog. As my husband was building it I would read it to him (not saying he did what I told him). LOL
I still have a leak in one of the corners but started putting plants in it anyway. I did get him to put a wooden frame inside so I can hang my plants. This picture was in Sept as he was building it. I did get him to put more boards across the top so I could do all my hanging plants. I hope the picture shows up this is the first time I'm trying to post one. Loquinn I have to many plants for shepherd hooks and they don't seem to work for me.

clp1899, that looks like a great solution! Thanks so much for posting the photo. I recall having some very small leaks in my corners too, at the top of the corner posts.

As best I can remember, I used silicone caulk to fill the gaps. I wasn't worried about a few dribbles of rain, but I was worried about largish gaps that could leak out warmed air during the winter months.

I hope you enjoy your greenhouse.