To plant potatoes in a garbage can, you get a garbage can and drill several 1/2 drainage holes in the bottom and on the sides close to the bottom. You then fill it with about 6 inches of good potting soil, and if you like, some fertilizer. I personally am going to use the "square foot gardening" mix of 1/3 peat moss, 1/3 compost and 1/3 asbestos-free vermiculite.
You then plant a few seed potatoes in this six inches of soil, leaving at least five inches between each seed. You cover these seed potatoes with soil (about an inch), and water them.
These will sprout. When the vines grow 4" high, you add compost, more soil, or straw to the garbage can, covering all but 1" of the vine. You keep doing this until the garbage can is completely full. You then have the seed potatoes at the bottom and several plants that have grown up to the height of the garbage can. Stake up the vines that grow out of the top. The vines will flower, and then potatoes will grow all up the length of the vine. You can dig right in whenever you want a potato. When you dig in to get one while the vine is alive, this is a "new potato" and is for eating soon. They are extremely tasty fresh from planting. But a "new potato" will not store long. When the vines have died at the end of the summer, the leftover potatoes are storable.
I've never done this before, but I know people who have and have gotten 40 lbs of potatoes or more from a can. I'm doing it this year. Mmmm...
You shouldn't need to stake the vines. Potatoes don't grow more than 12-15" high above the soil. Pay close attention to the water needs - plants in containers dry out much faster than those in the ground.
I've never done this, and I always wonder how the small plant gets enough sunlight to sustain it's growth while deep down in the can. I may have to try this too.
