I set up my Rion 8x12 "Hobby Greenhouse", the green one, over six years ago (photo below). No structural or deterioration problems, and no panel failures of any sort. The green finish has dulled, much like you get on a fiberglass boat. (The GH was new when the photo was taken.) Living in lower Alabama (sub-tropical), I ordered a custom kit with double doors in both ends, four vents and a shade cloth. This provides great ventilaiton - the secret to keeping it below the melting point. No yellowing of poly panels except in the south-facing doors, which stand open all summer with the unprotected side to the sun. (should have turned the panels around years ago, but too lazy.) Located in lower Alabama, it sees mild winters, hot humid summers, occasional strong thunderstorms, but no hurricanes yet. As noted by others, air sealing is something the factory leaves largely up to you, and it takes considerable observation and ingenuity to plug all the air inlets, somewhat akin to the structural enhancements the Harbor Freighters have to contend with. Also, as noted by others, water sealing is an ongoing process. In my case, I had water leaks under all four vents. I finally cured the leaks by taping all the seams around the vents with Nashua Waterproofing Tape (photo below). The tape has lasted several years now and still looks new, again in a sub-tropical climate. The Rion Hobby Greenhouse looks like a big kid's toy. But it's not. It's made very precisely, and you have to assemble it exactly as the manufacturer intends (but sometimes does not explain very well), perfectly square and level. That pesky stripping that secures the poly panels and the torsion wires across the top look easy, but are particularly tough to get right. Structurally, the greenhouse sort of hangs by it's thumbs, i.e. everything about it contributes to its structural integrity. It helps enormously if you have built many things before taking on a Rion. I would posit that a much of the trouble people have with the Rion derives from their inexperience in building things, or just plain old carelessness and inattention to detail. With all due respect, if you lack building experience, or otherwise have trouble figuring complex things out, you might need to get experienced help in setting up a Rion. Rion Greenhouse: Nashua Tape:

Thanks for the feedback, cuestaroble. I had wondered about the single wall, I think they have some sort of corrugated shaped foam to seal the end pieces, but I do think a twin-wall product would be better than trying to create some kind of "air pocket" after the fact with bubble wrap, plastic, etc. It sounds like the more vents the better, here in Zone 7. I'd originally wanted to custom-build a greenhouse out of mostly sliding patio doors so that I could really VENT it (even my tiny 6x8 HFGH was an oven on sunny days, and that was missing half its panels). When I saw this, I thought a similar pricepoint but without me doing all the work sounded great. But might be too good to be true. The fabricator is supposed to call me when he next brings a shipment to our area so I can go look at in person. We shall see and I will update then. Any other feedback or comments in the interim are welcome!

You may have better luck in the greenhouse forum. Here we plant seeds in winter without a greenhouse. Here is a link that might be useful: Greenhouse forum

With help & experience of my fellow GW friends, I have ruled out 2 of my three choices above. I am now thinking about either getting the SpringHouse model or one of the small PlantHouse, StarterHouse, SeedHouse or Plant Tower models on This Page. I would so so much rather have the SpringHouse & it appears to have great reviews compared to what were my other two choices above. No one on here, so far, has said anything bad about their experiences with it. It appears to be better constructed than the "First Choice" & "Yet Another Choice" linked ones above in my original post. So, please let me know your final opinions on my newest choices. =) Keeping in mind, I not only want it for the early season seed starting (which is about all i'd be able to do in the smaller ones), but also for Winter tropicals storage, non-hardy plant storage & kind of a workshop of sorts for propagation, etc.. Thanks! - Steve