Home gardeners often purchase certified seed potatoes by weight, typically in pounds. Unlike buying produce, seed potatoes are the starting material for new plants, not the final meal. The number of individual tubers within a single pound is highly variable, depending on the physical characteristics of the potatoes. Determining the approximate count is necessary for calculating planting needs and ensuring the garden space is adequately covered.
Factors Determining Seed Potato Count Per Pound
The count per pound varies primarily due to the size and variety of the seed potato. Different potato types mature into distinct shapes and sizes, directly impacting their weight distribution. For instance, large, blocky varieties like Russets may yield only four to six whole tubers per pound because they are heavy. Conversely, smaller, elongated varieties, such as fingerlings, can result in a much higher count, sometimes containing 8 to 12 individual potatoes per pound due to their lower mass.
Seed potatoes are typically graded to weigh between 1.5 and 3 ounces each. This standardized weight range means a pound usually contains five to ten whole seed potatoes, accommodating most common varieties. When purchasing by weight, a gardener is buying the total mass of plantable material. Size remains the dominant factor in determining the count.
Preparing Seed Pieces for Planting
After acquiring whole seed potatoes, the next step is converting them into plantable units called seed pieces. A seed piece must contain at least one healthy “eye,” the bud from which the new plant sprouts, though two or more eyes are preferred. Small seed potatoes (under 1.5 ounces) are often planted whole, as cutting them creates pieces too small for vigorous growth. For larger tubers, the goal is to cut blocky sections weighing between 1.5 and 2.5 ounces each. This size provides the sprout with enough stored energy to establish a robust root system.
Before planting, seed pieces must undergo curing or callousing. This involves spreading the pieces in a single layer in a cool, dark, and moderately humid area for two to four days. This exposure allows the cut surfaces to dry and form a protective, leathery layer. This layer acts as a barrier against soil-borne pathogens and prevents the seed piece from rotting. Another preparatory technique is “chitting,” where whole tubers are exposed to light and moderate temperature for a few weeks to encourage short sprouts before cutting.
Spacing Requirements and Planting Density
The prepared seed pieces are placed into the garden bed according to specific spacing guidelines. Standard in-row spacing ranges from 10 to 15 inches between each seed piece, allowing room for tuber expansion. Row distance is typically set wider, between 30 and 36 inches, to allow space for hilling.
Hilling involves continuously mounding soil over the stems, which encourages the formation of more potatoes. Gardeners aiming for smaller, “new” potatoes can use closer in-row spacing (8 to 9 inches). Conversely, spacing plants further apart (up to 20 inches) encourages the development of fewer but larger tubers suitable for storage.
Calculating the required pounds of seed potatoes connects the count per pound with the final garden layout. One pound of cut seed potatoes can plant approximately 5 to 8 row-feet, or about one to two pounds are needed for every 100 square feet of garden space. Using these guidelines helps determine the planting density required for the desired harvest size and type.