For those of you who looked into this thread because you thought, "What the heck is a Walpini?!?!" It is an underground greenhouse for year around gardening. Now you can continue your browsing and have learnt your something new everyday. ANYWAY I found out about walpinis (spelling? Walapini maybe?) and am enthralled. I want to build one this summer!!! I've got a few questions. What type of plastic are we talking about for the roof? Like, sheet plastic or more down the plexi-glass plastic road? Do you need a specific type of plastic? Will this work in Northern Iowa? How deep? Is 6' deep enough? I am thinking about a 10'x10'...is that big enough to be warm enough? Am I crazy to think about maybe hand digging it?!?! I do have access to a backhoe-ing neighbor. That would be easier and saner, huh? Do you have problems with deer walking on it? Any tips for keeping it warm? How do you access it? Besides a slide. That'd be awesome. What can you grow in one of these babies? I HOPE someone has heard of a Walpini! Even if you can't answer my specific questions, or just have an answer to even 1, PLEASE PLEASE PLEASE PLEEEEASE post anything you know, or a picture of your Walpini! THANK YOU!!!!!!!