Buy seed potatoes of early varieties for planting as soon as soil can be worked in the spring.
In the North, plant seed potatoes of later varieties from mid-May to early mid-June, 4 to 5 weeks after planting early varieties. In the South, plant seed potatoes of late varieties 1 to 2 weeks after early varieties.
Cut seed potatoes into small pieces with two to three eyes per piece a few days before planting.
Dig trenches 6 inches wide, 8 inches deep, and 30 to 36 inches apart. Spread 5-10-10 at a rate of 1 pound per 25 feet or its equivalent along the bottom of the trench and cover with 2 inches of soil.
Plant small whole seed potatoes or cut seed pieces 10 to 15 inches apart in the trench and cover with about 4 inches of soil.
Protect emerging plants with soil or other cover in case of a hard late spring frost.
Hill the soil up against the plants about a week after leaves emerge from soil. Repeat 2 to 3 weeks later.
Side-dress when you hill for the second time with compost, seaweed, or fish emulsion, or about 1 pound of 5-10-10 per 25-foot row.
Be sure to provide adequate water 6 to 10 weeks after planting, when the potatoes start to form.
See our article Summer's Bad Guys by Charlie Nardozzi for controls of common potato pests such as Colorado potato beetle, European corn borer, and leafhoppers.
Harvest small, new potatoes about 10 weeks after planting.
Harvest storage potatoes after the vines have died and tubers have developed tough outer skins. In the North, harvest before fall frosts arrive.