I don't have optimal soil or sun conditions, and a really full garden, so my space for a veggie bed is limited. A few years ago, I started growing vegetables in containers, sneaking them into sunny spots between perennials and shrubs, here and there throughout the garden. I've discovered many vegetables grow well in containers--tomatoes, peppers, zucchini, eggplant, carrots, beets, turnips, squash, and even potatoes. Actually, especially potatoes! Here's how to do it.
Last year I grew 'Bintje' (above). This year I'm growing 'German Butterball,' 'Purple Peruvian,' and 'Red Norland,' all purchased as seed potatoes (the first three from Landreth, the latter from locally-owned Downtown Home and Garden).
Seed potatoes are not actual seeds; they're mature potatoes that we cut up and plant. If you get your seed potatoes a month or so before planting, store them in a cool, dry, dark place at about 50 degrees. (If you're storing potatoes throughout the winter, requirements are different. I'll write about that in fall.)
You can use any large container, provided you drill drainage holes into the bottom. I use plastic storage bins because they're lightweight and inexpensive. They're on sale now for back to school and will be again after the holidays. I got the one shown here at a big box for $4 after Christmas.
My bin is 18" deep, 18" wide, and 25" long, and I wouldn't go any smaller than that, especially not in depth. I drilled holes (7/32" bit) along the bottom edges and in parallel rows, lengthwise. You do not need the lid. I move mine around the garden as a weed suppressant.:)
For filler, I like a 70/30 combo of compost and a good soil mix. The City of Ann Arbor gives out free compost in spring, so I load up there. You can adjust the ratio for your own needs. Potatoes don't need rich soil, but I think they grow much better in a container with it.
Fill your container about a third with your soil/compost mix. Plant each potato piece so it's sitting about an inch from the bottom of the tub and is covered in the rest of the soil. Plant so a cut edge is facing down and the eyes are facing up. I want to tell you I planted the pieces 6 inches apart, but it was likely more like 3 inches. I varied the planting depth a little, to create more space.
Potatoes like full sun, so if you have it, great! If you don't, don't worry. Potatoes are forgiving. Once my trees leaf out, my bin only gets four to six hours of a sun a day and the potatoes did fine.
In-ground potatoes can be planted when soil temperatures reach 45F. I plant mine in the bins at the end of April here is southeastern Michigan, where the last frost date is mid-May.
As the potato stalks grow, keep adding more soil into the bin in stages. This is not an exact science; I add 2 inches each time the foliage gets to be about 8 inches over the soil line. When you've added enough soil to be about 2 inches from the top of the bin, stop filling it. You need at least that amount of clearance so that water has a place to collect without overflowing in heavy rainfalls.
I'm going to do a second planting in the next few days, as soon as I harvest everything currently in the bin. I'm not sure if there's enough time for a second harvest, but I'm going to see what happens. Three months from now will be Halloween. Since potatoes can handle some cold, I'm hoping they will finish by then. I'll let you know.
Another advantage to growing in a bin is you don't have to worry about crop rotation. I dump the compost/soil mix onto my veggie bed at the end of the season, wash the container with a solution of 9 parts water to 1 part bleach, and fill it with fresh soil next year. I can use the same container over and over again, and I save some potatoes to start next year, too.