Digging down below a greenhouse kit for thermal mass?

Hello, we recently acquired a very nice glass greenhouse kit very cheaply, and we’re making plans to build it before the fall. Has anyone ever dug down a couple of feet or so to make your greenhouse partially sunken, but also used a kit with a set height? I’m curious about the net impact on temperatures of having the resulting high ceilings.

I did this with a kitset glasshouse. Dug down 70 cm (with the help of an energetic 16-year-old nephew) and then poured a perimeter wall foundation with anchor bolts sticking out the top. I used the bolts to attach timber sill plates, which were easy to get level and straight enough to bolt the aluminium frame directly on top.

It's been nice having the extra head space and some thermal flywheel effect from the ground. When it's really sunny the hottest air is above where most of the plants are. The floor is a bit of a cold sink and I would like to remedy that at some point, maybe with a fan that runs when the RMH is going.

Sarah, you don't mention the size of the footprint, or the ecosystem you're working with, but most of the smaller greenhouses I've met could really use both the height and the thermal mass effectively.

You always have the option of using some sort of sheeting to lower the ceiling when the weather needs that. For example put some plastic tenting over trays of seedlings in the spring if the night temperature drops too much.  There are some heat loving beans and plenty of tomato varieties which will grow very tall if you allow them to and have a plan for picking the fruit easily.

Go down this road a bit and you may find some useful info.

https://www.google.com/search?q=walipini+greenhouse&oq=wallapini&gs_lcrp=EgZjaHJvbWUqCQgBEAAYChiABDIGCAAQRRg5MgkIARAAGAoYgAQyCQgCEAAYChiABDIJCAMQABgKGIAEMgkIBBAAGAoYgAQyCQgFEAAYChiABDIJCAYQABgKGIAEMgkIBxAAGAoYgAQyCQgIEAAYChiABDIJCAkQABgKGIAE0gEIODc1MWowajeoAgCwAgA&sourceid=chrome&ie=UTF-8