Russet potatoes are valued for their high starch content, making them ideal for baking, mashing, and long-term storage. A successful harvest that maximizes yield and storage life depends on precise timing and careful technique. Harvesting too early results in thin-skinned tubers that spoil quickly, while waiting too long risks damage from pests or weather. Understanding the plant’s life cycle and recognizing maturity signs are necessary for gathering a quality crop.
The Russet Potato Growing Timeline
Russet potatoes are categorized as late-season or maincrop varieties, requiring a longer period in the ground to fully develop their size and characteristics. Most Russet varieties reach full maturity between 90 to 120 days after planting, though some cultivars may require up to 135 days depending on the climate and growing conditions. This range provides a calendar-based guide, but it is not the sole determinant for harvest readiness.
Smaller, thin-skinned “new potatoes” can be harvested approximately 7 to 8 weeks after planting while the foliage is still green. This is distinct from a main harvest, as these young tubers are intended for immediate consumption and will not store well. For the long-term storage Russets are known for, the full growing period is required to ensure the tubers bulk up and their skins achieve the necessary thickness.
Visual Indicators of Harvest Readiness
The most reliable sign that Russet potatoes are ready for a main harvest is the natural dieback of the plant’s foliage, known as the vines or tops. The leaves and stems will yellow, wilt, and eventually turn brown and die back completely. This process indicates the plant has finished growing and is diverting energy into thickening the skin of the underground tubers.
It is important to wait until the tops have been completely dead for at least two to three weeks before digging. This waiting period allows the potato’s skin, or periderm, to “set,” meaning it toughens and adheres firmly to the tuber flesh. Harvesting before this skin-setting period results in “feathering,” where the thin, immature skin easily rubs off.
The maturity of the skin can be physically tested by gently digging up a single test potato and rubbing the skin with a thumb. If the skin easily peels or rubs away, the tubers are not yet ready for long-term storage and require more time in the soil. The tough, set skin is crucial because it acts as a protective barrier against moisture loss and pathogens during storage.
Essential Harvesting Techniques
Harvesting must be performed with great care to avoid bruising, cutting, or skinning the tubers, which compromises their storage potential. Reducing watering for one to two weeks before the planned harvest date helps toughen the skin and makes the tubers less susceptible to shatter bruise. The best time to harvest is on a warm, dry day when the soil is slightly dry, which prevents the soil from sticking excessively to the potatoes and makes lifting easier.
Begin digging well outside the estimated perimeter of the plant, typically 12 to 18 inches away from the main stem. This distance ensures the digging tool, usually a garden fork, does not slice into the tubers, which grow outward. Gently push the fork into the soil and use the handle to lift the soil and the potatoes, rather than trying to pierce the hill directly.
Once the soil is loosened, carefully lift the tubers and separate them from the soil by hand. Minimize handling and avoid dropping the potatoes, as impact damage can cause blackspot or shatter bruising later in storage. Any potatoes that are cut, bruised, or skinned should be sorted out and used immediately, as they will not last in long-term storage and can introduce rot to the rest of the crop.
Curing and Preparing Russets for Storage
Immediately following harvest, Russet potatoes intended for long-term keeping must undergo curing. Curing is a period of specialized warm and humid storage that allows the tubers to heal minor scrapes and fully thicken their skins. This healing process creates a durable protective layer against pathogens and moisture loss.
The ideal environment for curing involves placing the potatoes in a dark, well-ventilated space with a temperature range of 55°F to 60°F and high relative humidity, ideally between 85% and 95%. The curing process typically takes 10 to 14 days. During this time, the potatoes should not be washed; only gently brush off large clumps of soil, as washing can decrease storage life.
After curing, the potatoes are ready for long-term storage, which requires different environmental conditions. The temperature should be gradually lowered to a cooler range of 40°F to 45°F, while maintaining high humidity around 90%. Storing the potatoes in a dark location prevents greening, which is caused by light exposure and indicates the presence of the toxic compound solanine.