Successful potato cultivation depends on understanding the plant’s specific growth habit. Varieties use one of two primary strategies for developing tubers underground. Knowing the strategy dictates the necessary planting and maintenance techniques. This article clarifies the distinction between the two growth types and classifies the popular Kennebec potato, detailing the implications of its habit for the home gardener.
Defining Determinate and Indeterminate Potato Growth
Potatoes are categorized based on where new tubers form relative to the original seed piece. Determinate varieties produce their crop in a single, concentrated layer just below the soil surface. These varieties mature quickly, often within 70 to 90 days, making them suitable for regions with shorter growing seasons. Tuber production generally ceases soon after the plant flowers, limiting the overall yield potential.
Indeterminate potatoes, by contrast, form tubers along the subterranean portion of the stem, known as the stolons, in multiple vertical layers. As the plant stem grows upward, new layers of tubers develop above the older ones. Indeterminate types require a longer growing period, often 110 to 135 days to reach full maturity, and they continue to produce new tubers as long as the plant is actively growing.
Classifying Kennebec Potatoes
The Kennebec variety is a main-season potato, prized for its high yields, excellent storage qualities, and versatility. Although some sources group Kennebec with determinate varieties, its performance aligns more closely with the indeterminate growth type. Kennebec plants exhibit the vigorous stem growth and extended production cycle characteristic of indeterminate potatoes.
This variety benefits from gardening practices associated with indeterminate types, which focus on encouraging vertical tuber formation. The high yield of Kennebec is directly tied to the plant’s ability to set tubers along a greater length of its buried stem. Therefore, Kennebec is best treated as an indeterminate potato requiring continuous attention to maximize its potential harvest.
Kennebec’s main-season designation means it needs a longer duration in the soil to fully develop its large, round-to-oblong tubers. This extended growth cycle allows the plant to form multiple layers of potatoes along the stem, a process dependent on the gardener’s intervention. Treating Kennebec as indeterminate ensures the plant is provided the necessary conditions to achieve full yield and maturity.
Practical Hilling and Harvesting Strategies
Because Kennebec is treated as an indeterminate variety, the practice of “hilling” is mandatory and repeated. Hilling involves progressively mounding soil or organic matter, such as straw or compost, around the growing stems. This process serves a dual purpose: it protects developing tubers from sunlight, preventing them from turning green and becoming inedible.
Hilling provides the necessary environment for Kennebec to form additional layers of tubers along the buried stem. Hill the plants whenever the foliage reaches about six to eight inches in height, covering all but the top few inches of leaves. This should be repeated two to three more times as the plant grows, creating a substantial mound that increases the total surface area for tuber development.
The longer growing cycle of indeterminate potatoes dictates a different harvesting schedule than earlier varieties. Kennebec should remain in the ground until the foliage has completely died back and yellowed. This waiting period allows the tubers to fully mature and their skins to thicken, maximizing their storage life. Once the foliage has died, waiting an additional one to two weeks before digging allows the skin to fully set, reducing the chance of damage during harvest.