The space required for a potato plant is a dynamic combination of horizontal separation and vertical depth, both adjusted as the plant grows. Providing the correct amount of room maximizes the plant’s yield and ensures good air circulation, which helps prevent common diseases.
Standard In-Ground Spacing
When planting potatoes in traditional rows, the horizontal space is divided into the distance between individual plants within a row and the distance separating the rows themselves. The spacing you choose directly influences the size of the resulting tubers. For most varieties, placing the seed potatoes approximately 10 to 15 inches apart within the row is the standard practice.
Closer spacing, such as 7 to 9 inches, tends to produce a higher total number of potatoes, but the individual tubers will be smaller and are often marketed as new potatoes. Conversely, if the goal is to harvest large, mature potatoes for storage, widening the in-row distance to 15 to 20 inches allows each plant to develop its maximum potential. Between rows, a space of 2.5 to 3 feet (30 to 36 inches) is necessary to provide enough room for the foliage to spread and to allow access for cultivation.
This wider separation between rows promotes sunlight penetration and maintains adequate air circulation, both of which reduce the risk of fungal diseases. The initial planting depth for the seed potato should be about 4 to 6 inches deep in the soil. This depth is a starting point, as the plant’s subsequent growth requires additional vertical space to be added over time.
Vertical Space and Hilling Needs
Potatoes are tubers that develop along the underground stem, or stolons, above the original planted seed piece, which means they require increasing vertical space as they grow. This is why the process called “hilling” is a fundamental part of cultivating potatoes. Hilling involves progressively pulling soil up around the stem of the plant as it grows.
The purpose of hilling is twofold: it encourages the buried stem to produce more stolons, thus potentially increasing the number of tubers, and it shields the developing potatoes from light exposure. Tubers exposed to sunlight turn green due to the buildup of solanine, rendering them inedible. The first hilling should occur when the plant’s shoots reach a height of approximately 6 to 8 inches above the soil surface.
During this process, the soil is gently mounded around the base of the plant until only the top third of the foliage is visible. This action is repeated two or three more times as the plant continues to grow, typically every two to three weeks. The final result is a deep mound that provides the necessary vertical depth to protect the growing crop.
Container and Raised Bed Requirements
For alternative planting methods, such as containers or raised beds, the space requirement shifts from linear rows to a necessary volume of growing medium. When using containers, a single potato plant requires a minimum of 5 to 10 gallons of soil volume to develop a healthy yield. A 10-gallon container is generally considered a good size for a single plant, while a 15-gallon container can often accommodate two to three plants, depending on the variety.
Suitable containers include specialized fabric grow bags, large barrels, or plastic storage tubs, all of which must have adequate drainage holes. The hilling process is adapted in these setups by simply adding more growing medium, such as compost or straw, in layers as the plant grows, effectively filling the container. This layering provides the vertical space needed for tuber formation.
Raised beds offer a middle ground, providing better soil drainage and aeration than in-ground planting, which allows for slightly denser spacing. In a raised bed, seed potatoes are often spaced around 12 inches apart in all directions, or even as close as 10 inches for early-season varieties.
The initial planting depth is similar to traditional planting, about 4 to 6 inches, but the surrounding walls of the raised bed make hilling easier. Instead of forming a ridge, the soil or organic material is simply pulled from the surrounding bed up against the stems until the bed is full, ensuring the developing tubers are always covered and reinforcing that the correct space depends entirely on the chosen method.