More to explore:
Amish cold frame
Constructing a cold frame from old windows
My window well DIY cold frame!
How to Build a Removable Cold Frame on top of your raised veg beds...
Greenhouse in the backyard :)
Make Your Own Greenhouse.
Build Your Own Add-On Greenhouse DIY Project... It's a snap to design and build your own attractive conservatory from low-cost new and salvaged materials.
Make Your Own Greenhouse