Potatoes are a cool-weather crop, and successful cultivation in Virginia depends entirely on proper timing. They thrive when planted early enough to develop tubers during the mild spring and early summer, before the intense heat inhibits growth. Knowing precisely when to plant the seed potatoes is the most important factor for maximizing the harvest. This timing is dictated by both the soil temperature and the specific microclimate of your region.
Determining the Optimal Planting Schedule for Virginia
The ideal time to plant potatoes is when the soil temperature consistently reaches at least 45°F, usually two to four weeks before the average last frost date. Planting in warm soil prevents the seed pieces from rotting in cold, wet conditions and encourages rapid sprouting. Although 45°F is the minimum, the goal is to plant early enough so the plants are established by the time the soil warms to an optimal 55°F.
Virginia’s diverse geography requires a regional approach to planting. In the Coastal Plain and Tidewater regions, planting can begin as early as mid-March, extending through the first week of April. Gardeners in the Piedmont region should wait until late March or early April to avoid a late cold snap. Planting in the cooler Mountain and Valley regions should be delayed until mid-to-late April, since the last expected frost date is later there.
Preparing the Soil and Seed Potatoes
Successful potato cultivation requires a growing medium that is loose, well-draining, and rich in organic matter. Potatoes perform best in slightly acidic soil, ideally with a pH between 5.5 and 6.0, which helps suppress the common potato disease known as scab. Amending the area with well-aged compost improves structure and fertility. Avoid fresh manure, as its high nitrogen content promotes excessive leafy growth instead of tuber development.
Before planting, seed potatoes should be pre-sprouted, a process called “chitting,” to give them a head start. To chit, place them in a single layer, with the end containing the most “eyes” facing up, in a cool, bright location for four to six weeks. This encourages short, sturdy sprouts, which are more robust than those that form in the dark. Larger seed potatoes should be cut into blocky pieces, weighing 1.5 to 2.5 ounces, ensuring each piece has at least one or two eyes. Allow the cut pieces to dry for a day or two to form a protective, cork-like layer, which prevents rot once planted.
Planting Techniques and Early Season Care
Plant seed potato pieces in a trench or furrow four to six inches deep, with the sprouts facing upward. Space the pieces 10 to 12 inches apart within the row, leaving 30 to 36 inches between rows for hilling. Consistent soil moisture is important once the plants emerge. Aim to provide roughly one inch of water per week, adjusting for natural rainfall.
Hilling is the most distinctive technique for potato care, involving mounding soil up around the base of the plant. Begin hilling once the plant reaches six to eight inches in height, and repeat the process every time the plant grows another six inches. Hilling primarily shields developing tubers from sunlight, which is necessary because light exposure causes them to turn green and produce solanine, a mildly toxic compound. Continuously burying the stem encourages the plant to produce more tubers along the buried portion, increasing the potential yield.
Knowing When and How to Harvest
The harvest timeline depends on whether you seek new potatoes or mature potatoes for storage. New potatoes are small, thin-skinned, and best for immediate consumption. They can be gently dug seven to eight weeks after planting, often coinciding with the plant’s flowering stage. At this early stage, you can carefully feel around the plant’s base to harvest a few small tubers without sacrificing the plant’s ability to produce a later, main crop.
For mature potatoes intended for long-term storage, wait until the plant foliage naturally begins to yellow and die back, a process called senescence, which usually takes 100 or more days. Once the tops have completely withered, wait an additional two to three weeks before digging to allow the skins to fully thicken, or “set.” When harvesting, use a garden fork inserted a full foot away from the main stem, gently lifting the entire mound to avoid spearing the tubers. Mature potatoes should then be cured for 10 to 14 days in a dark, humid environment (50°F to 60°F) to heal any minor skin damage before placing them into cool, dark storage.