Mini greenhouse ~ Cut the bottom off a gallon milk jug and when a cold snap is in the forecast, place the jug over your plant, to keep warm in early Spring and Fall. Lots of other 25 No-Cost (or Low-Cost) Garden Tools
A 'green' compost container. komposti
30 Fascinating Low-Budget DIY Garden Pots
The vertical garden is a space saving way to grow up to 72 small plants (such as lettuce, spinach, strawberries and lots of different herbs) all with the plant health benefits of hydroponics.