I am writing a book on year-round solar greenhouses and I would love some contributions from those who have had underground greenhouses (or the variation of a walipini). Looking for those who have built or been growing in one. Specifically, I would love to incorporate high-res photos (the original file, not uploads) in the book. They will be attributed to you. Any other reviews of an underground greenhouse / walipini that you have built I would love to know as well. If you have photos you can purple moose (PM) me... a phrase I never expected to say... and we can get in touch by email perhaps. Or, post experiences below.
I hope to make it a comprehensive resource; your help is appreciated.