For those who grow their own (or shop the farmer’s market), there can be spuds in a range of colors from blue to white to red and yellow. They come small as your thumb (fingerlings such as ‘Austrian Crescent’ are great for potato salad, or for roasting). Others are as large as a pound-and-a-half meal (‘Nooksack’, a whopping russet-skinned type that could support a whole container of sour cream). Best: You can harvest baby potatoes and eat them minutes later, which is one of vegetable gardening’s greatest rewards, right up there with the first ripe tomato.
Choose not just for size and color but also for texture, since potatoes may be mealy or smooth. It likewise makes sense to stagger the harvest by selecting some early varieties (65-plus days to harvest), midseason (85-plus days), and late (90-plus). Potatoes go into the ground early, but according to conservatives that means a week or two before the final frost, like late May for me. In cooperative years, when the soil is workable and no longer sodden and cold, I jump the gun and get them in at the end of April. They won’t start growing until the soil reaches 45 degrees; they will rot if it’s cold and wet. Under ideal conditions, potatoes will yield about 14 pounds per pound of seed potatoes planted; I haven’t achieved those results, but I keep trying.
They do best in a light, loose and slightly acid soil that is kept weed-free while they grow. Plant in 6-inch-wide, 6-inch-deep trenches, leaving about a foot to a foot and a half in the row between each seed potato (a smallish potato, or a wedge of a larger potato that was cut to include some eyes, then allowed to cure a few days in the air before planting). As the foliage emerges and gets near a foot tall, I hill the plants up with extra soil.
Here’s where the work comes in. Where does the needed soil come from? Since my soil is not rocky or too heavy, I sometimes dig a deeper trench to start with, leaving the loose excavated soil along each side of the trench. At hilling time, I just move it back onto the row of plants, never covering the foliage completely, but simply most of the way. When the plants grow up a bit again, I mulch them with a thick layer of oat straw.
An even easier method is to merely lay the seed potatoes on top of soil in a row, a foot apart, then heap 6 to 8 inches of straw or hay mulch on top of them. Each time the shoots of the potato plants emerge, top-dress with more mulch; water regularly. Back-saving gardeners who use this method rave about the simplicity, and also about the clean potatoes they harvest, which were never underground. Potatoes are so eager to grow (as anyone who has kept a bag of them too long in the kitchen will confirm) that they can even be grown in a compost heap or a bin (as long as it has slits or holes for water and air).
Order from a specialist like Ronniger’s or Fedco Moose Tubers, who have extensive collections and lots more tips to help you succeed. Whichever method you choose, do not give them lots of nitrogen (you’ll get leaves, not tubers) or any lime, and be generous with the watering and sunshine. Best not to plant potatoes in the same place within three years of the last potato crop or another Solanum relative; they must be rotated.
New potatoes (dig just what you’ll use each day) can be harvested carefully starting about two to three weeks after flowering of the plants stop. Or let them keep growing.
I leave my potatoes in the ground and use them from there as needed well into the fall, then dig the rest carefully, working slowly so as not to pierce the tubers, and let them cure a bit in the last sunny days on the picnic table before putting them in bushel baskets in a spot where it is cool and dark, but not near freezing. (The details on potato harvest and storage.)
A sampling of the best potatoes of each variety (no, not the runts, or any at all if you experienced any diseases in your crop) can be carried over for next year’s starts, so long as they are still firm and vital when the time comes to plant again. The safest way is to order a fresh supply each year of “seed potatoes,” as the starts are called.