Kitchen garden inspiration - build an Amish cold frame. I love this clever design. No plans available (our Amish friends didn't even use plans to build our sheep barn), but there are 10 photos in this post showing construction details.
21 DIY Greenhouses with Great Tutorials: Ultimate collection of THE BEST tutorials on how to build amazing DIY greenhouses, hoop tunnels and cold frames! Lots of inspirations to get you started! - A Piece of Rainbow
The Garden Cold Frame As An Alternative To Useful Greenhouse. You might not know it from grandma times yes. They are a great way for your plants during the winter to help and extend the possible time for beaching of fruits and vegetables.
(((Winter Gardening)) A cold frame with a glass top can give you a growing season, even in Maine, and it's the easiest and most economical way to extend your harvest. Build the one described here, and you're on your way to fresh veggies year round.
Inexpensive Mini Greenhouses - These worked PHENOMENALLY for seed starting this year. It was nice to be able to easily carry them all in when there was a frost warning. I kept the lids on during the day to keep heat/moisture in. Love this idea!