A great greenhouse you could build from local materials.

[Braken]

This is the way to go, the frame for it found in any neighborhood.

http://www.frugal-living-freedom.com/build-a-greenhouse.html

A Greenhouse with plastic.
B Shop building with tin.
C Chicken wire/chain link fence, house wrap and 2" of mortar/stucco/quickrete could make a decent solid shelter. May have to beef up the supports, at least till the crete cured.

My shop is round topped with 2" conduit for rafters and wall studs, 3' spacing, jumping on top of it does not move it at all.

[Mr.Pliskin]

I dont have as much room as that guy. Mine's just a bunch of 2" PVC bent over into the ground with 6mil clear plastic clamped over the top that was free from a greenhouse. Its about 5" high and 15-20 feet long and I can move it to a new location if I want to "rearange" the back yard.