Energy Efficient

The university of Missouri-Colombia in the US has put out an excellent design for an energy efficient greenhouse. It involves using raised beds to maximise heat received by plants and black drums filled with water that soak up the heat in the day and release it at night.

Foldable Plastic

Dutch designer Daniel Schipper has created a greenhouse design that could possibly be made out of recycled plastics and is also completely foldable.

Plastic Bottles

REAP, a sustainability group in the north of Scotland came up a design based on plastic fizzy drink bottles. They cut the bases out of each bottle and fitted them inside each other along a garden stake. These are then assembled onto a frame. They have put an instruction guide together, and you can get it here. There is also a good photo of it here.