Inspired by the Topsy Turvy, these great upside down tomato planters can be created from little more than a 2 liter bottle or a milk jug. These would work great for a place where floor space is limited or for an inexpensive vertical garden.
The folks over at Cheap Vegetable Gardener have been experimenting with a few different types of upside down gardens using little more than recycled beverage containers. The first, from a 2 liter soda bottle, was simply covered with duct tape and a hole for drainage (pictured above). That's evolved and improved however into the spray painted, slow-drip water reservoir equipped version pictured below.
The third was constructed by a 1 gallon milk jug which contained more soil and has extra water capacity, but is hard to balance. See complete instructions and photos for how these were all made over at the Cheap Vegetable Gardener.