I’ve had several people ask what the process of building a Greenhouse in the Snow (geothermal) has been like. In this thread I’ll detail what we have accomplished thus far in case it might help someone else.
June 2025- the first real step (after ordering the kit and deciding on location, which happened in 2024) was hiring a local excavator to dig and lay the loop system at 8 feet and 6 feet, then backfill to 4 feet (the floor of the greenhouse). Although an open pipe system was an option, due to our high water table and past flooding, our excavator recommended this closed loop system.
The next step, building a retaining wall for the raised beds, we decided to do ourselves to save money. We purchased several pallets of cement blocks, dug a small trench for them, and started stacking blocks. This process took the entire summer and led to several arguments. I highly recommend hiring someone to do this part too, haha.
We know others who have used thick plastic panels with a wooden frame, but some of theirs are starting to bow or sag, and my hubby suggested that cement should last forever. Have I mentioned I now hate cement blocks?
What is the little pipe that’s laid in loops? Is that the buried lines for geothermal? Does it carry water? I would have expected big pipe, 4-8 inches, to circulate air.
Following this, the geothermal angle is interesting. The retaining wall lesson is universal though, my rule now is anything involving cement blocks and a spouse goes straight to hired help. Looking forward to seeing how the thermal mass performs once it’s all closed in.
That’s greenhouse in the snow’s closed loop liquid-to-air system. Eventually we will fill it with propylene glycol. Most people do the open pipe air system and bury pipes around instead of under the greenhouse, but our excavator worried that ours would flood and cause problems due to a nearby river flooding 2 years ago (and delaying our dig for a full year). The pipes are at 8 feet and 6 feet (with dirt in between).
Our block laying was delayed a bit (July 2025) by a lovely derecho that swept through the town and downed several large trees, blocking our entrance (but fortunately missing any buildings other than my kid’s playhouse).
The pipes are between the walls and 2 to 4 feet under them as well. The structure is even farther out to the side (I’ll try to get pictures of that up soon.)
Finally done with the block wall, including adding rebar and cement in every other hole, and bonding coat to the inner wall (October 2025). I will be happy to never carry a cement block again, so this wall better last as long as I do. Too late in the season to start the frame, so that started in spring 2026.
Our first attempt at digging holes for the structure posts (Nov 2025), as no snow had fallen yet. There was much disagreement about placement. Every time we looked at the instructions, we had different ideas as to where things went. By Christmas we decided that we should hire a contractor to build the structure in the spring. (We love our Ego auger, which we used to dig the holes).
This is so impressive. I love that you tried to do it together. Construction and marriage just never go well together…congratulations on the decision to hire someone. My husband and I ended up having to GC the build of our house. We were a team through the hell managing awful sub after awful sub. It’s easy to be united against someone else screwing everyrhing up…once the other people are gone, different story!
June 2026, our contractor started installing the posts and the metal greenhouse structure. Hiring him was absolutely the right choice, because hubby and I clearly had no idea what we were doing. Our flock of ducks hung around, silently judging.
June 2026. Metal support structure complete, now showing installation of the siding on the north wall. I picked out red siding out of several potential colors and I am quite happy with this choice. This is when it started to look like a greenhouse (still a long ways to go though!)
