Triad -- This may not be the most aesthetically pleasing garden project, but it gets the job done. If you plant one pound of potatoes, you can get ten pounds in return. Have you ever gained so much from a black trash bag?
According to the DIY Network website, it's pretty easy and the benefits are huge. You can check out their website for specific details.
First, you need seed potatoes. You can't just use the ones from the grocery store. If a potato has any disease, it doesn't necessarily show up in the first generation but becomes more prevalent with every generation after that. Seed potatoes have been certified by a government agency to be disease free.
Then get a black trash bag and fill it with potting soil. A 30 gallon bag is about the right size. It needs to be black to absorb the heat. You'll want to roll down the sides of the bag to keep the sides from falling open and spilling the soil. Set it up in a sunny spot where it will stay. I learned the hard way, this project isn't portable.
When the potatoes are all done, just cut the bag open and there's your harvest!
DIY Network website