Dear Waterstar, Yes, I agree it is confusing! It took me many readings of Sunny John's site to understand how it works. I am not sure about the foundation. I think it is possible to excavate, install the tubing and then backfill the ground flat enough to put the greenhouse on brick but you probably need to mechanically compact the soil. You should insulate the heat sink around the perimeter to protect your heat from being siphoned away by the frost layer. About clay soils Sunny John says, "Our experience shows that heavier subsoils continue to act as good heat sinks if the tubing has 6" of subsoil above it (8" OC from the surface) You should go deeper if your soil mass is lower." Whether on not it makes sense for your greenhouse, I don't know. It seems to me that your greenhouse is a little small for this system but I have heard of people using SHCS in a small greenhouse and being happy with it. Sunny John did say that having the tubes at least 30 feet in length is optimal. For the greenhouse I am building it will only be 20 feet and I am using stone for the storage medium. I would not worry too much about soil/clay getting into the tubes unless you are in an area with a high water table. If you are, I would use stone because then the water can come in and out without bringing in any mud. Contact David Roper. He is wonderfully helpful!

katrina_gardener - a few of us went through nightmares assembling the 10x12, but as time passed and I tracked the posts here, it appeared that they really improved the instructions, etc. You will likely be very happy with the greenhouse. I made a few of the upgrades that gardenerwantabe described in his posts, including the cross-bracing at the top of the walls with rigid conduit, and aluminum angle-iron across the door. You asked about placing your unit on the ground. I did not choose to do that, as many did not. Personally, I built mine on 2x12 pressure treated lumber. If I were to do it again, since I am growing veggies, I'd use cedar. I learned of its availability several months later. Then I used lag screws to secure the greenhouse to the 2x12 footing. (I used some regular non-treated wood as a divider between the PT and the metal base because the chemicals in pressure treated lumber react badly to metals.) Others have used 4x6 timbers, for example. I used the 2x12 because I am in snow country and wanted a bit of height. The 4x6 results in a shorter step in and out of the greenhouse. When you receive it, read all of the directions start to end. That way you will have a sense of the assembly process. I discovered that knowing some steps that were coming ahead allowed me to better understand the prior steps and short-cut some of the assembly. Just make sure you get everything very square so that when you start installing the operable panels in the roof they will fit properly and open/close with ease. Post your questions and you will find there are many here with experience building the unit. You should be just as happy as many of us are. Here is a link that might be useful: My HFGH 10x12

I looked fot it on craigslist about 15 minutes AFTER you made this original post and couldn't find it. I would have driven to Macon THAT DAY to pick up that thing. I'm still looking for something like that for my backyard. I have the PERFECT spot for that very size (or a big bigger) right in my yard. Dora

About the doors: some people change the sliding doors to hinged doors, especially if they live in a snowy climate where ice can accumulate in the track. My sliding doors are still working fine though, in our warm climate here in southern NM, after over 8 years. The doors have been redesigned (and improved) on the 10x12 kits in recent years; probably they have been improved on the 6x8 kits also. You might try constructing the greenhouse using the sliding doors, see how it works for you, and then possibly change it later...? I do advise paying special attention to the installation of the doors, though, and be sure to read the directions carefully. On the earlier HF kits, it was possible to mis-install the doors by missing a few key details that made a huge difference. Some of the old "HFGH door problem" threads here refer to doors that were never installed quite right in the first place, so just a heads up. In this thread, yorkie89 did some wonderfully helpful posts, and great photos, about how they replaced the door in their HFGH. Ripping Out the Doors...HFGH And here's a link to wonderful blog by web4deb. If you scroll almost to the bottom of the page, you'll see a photo of how they changed out the doors: web4deb blog, Adventures of Bigelow Brooks Farm And, Dewey302 has a written a great Instructables post about his 6x8 Harbor Freight greenhouse, and he changed the sliding door to a hinged door: Dewey302 Building and Improving the Harbor Freight 6x8 Greenhouse I hope this helps a bit. If you haven't yet, I also suggest checking your new kits ASAP against the parts list in the back of the manual. Sometimes, kits are shipped missing a part, and it's so much better to find that out early...instead of when you are halfway through your build!