Container gardening offers a simple, space-saving solution for growing potatoes, even for those with limited yard space. This method is particularly useful when utilizing potatoes that have already begun to sprout, often called “chitting,” which gives the plant a head start. Growing potatoes in containers allows for precise control over soil quality and drainage, factors that influence the yield and health of the tubers.
Preparing the Seed Potatoes and Growing Environment
The success of container potatoes begins with selecting the correct growing vessel. An ideal container should be opaque and offer a capacity of at least 10 to 15 gallons per plant cluster, ensuring enough vertical space for tuber development. Containers should be 18 to 36 inches deep and must have drainage holes to prevent waterlogging and rot.
The growing medium must be light, well-draining, and rich in organic matter; standard garden soil is unsuitable because it compacts easily. A mixture of 50 percent soilless potting mix and 50 percent quality compost provides the necessary structure and nutrients. This blend maintains proper aeration and moisture while creating the slightly acidic environment (pH 5.2 to 6.5) that potatoes prefer.
Before planting, large sprouted potatoes should be divided into sections one to two inches in diameter. Each piece must contain at least one or two sprouts, or “eyes.” Allow the pieces to air-dry for one to two days until a protective, cork-like layer (a callous) forms over the cut surface. This callousing minimizes the chance of the seed piece rotting in moist soil.
Step-by-Step Planting and Initial Hilling
Begin by filling the container base with a four to six-inch layer of the prepared potting and compost mix. This initial layer establishes the foundation for the root system. Position the prepared seed pieces onto this soil bed with the sprouts facing upward, spacing them five to twelve inches apart to allow for tuber expansion.
Cover the seed pieces with an additional three to six inches of the growing medium. This provides the first depth of soil where tubers will form. Immediately after covering, thoroughly water the container until excess moisture drains freely from the bottom holes.
Container potato cultivation involves “hilling” or “earthing up.” This process is crucial because potatoes form their tubers along the buried portion of the main stalk. Initial hilling occurs when the emerging plant reaches six to eight inches above the soil surface. Gently add soil around the stem, covering it until only the top few leaves remain exposed. This stimulates the buried stem to produce more tubers, and this addition of soil is repeated throughout the growing season.
Watering, Fertilization, and Ongoing Care
Maintaining consistent soil moisture is important for container potato production, as the limited volume causes the soil to dry out faster than garden beds. The soil should be kept uniformly moist but never waterlogged, as excess moisture can lead to fungal diseases and tuber rot. Water deeply whenever the top one to two inches of the growing medium feels dry, ensuring water flows out of the drainage holes.
Potatoes are heavy feeders, requiring specific nutrients to support foliage growth and tuber bulking. A fertilizer with a low-nitrogen, high-phosphorus, and high-potassium ratio (e.g., 5-10-10 or 5-8-4) is recommended to encourage tuber development over excessive leafy growth. Begin feeding the plant when the shoots first emerge and continue with a liquid fertilizer application every two to four weeks.
Place the container in a location that receives a minimum of six to eight hours of direct sunlight daily to support tuber growth. Continue the hilling process every time the plant grows another six to eight inches, adding soil until the container is nearly full. Stop applying nitrogen-heavy fertilizer once the plant begins to flower, as the plant’s energy should shift entirely to tuber enlargement.
Recognizing Maturity and Harvesting Techniques
The signal that container potatoes are nearing maturity is a natural change in the above-ground foliage, or vines. The leaves will begin to yellow, wither, and eventually die back completely, indicating the plant has finished its growth cycle. For the best yield and storage quality, wait two to three weeks after the foliage has fully died down before harvesting.
If smaller, tender “new potatoes” are desired, they can be harvested earlier, typically seven to eight weeks after planting, once the plant has flowered and the tubers have reached a usable size. Harvesting container potatoes is easier than digging in the ground; simply tip the container onto a tarp or wheelbarrow. This exposes the entire crop without the risk of damaging the tubers.
Immediately after harvest, the potatoes should not be washed but gently brushed clean of excess soil. They must then undergo a “curing” process, which is necessary for long-term storage.
Curing for Storage
Curing involves placing the harvested tubers in a dark, well-ventilated area with high humidity (85 to 95 percent) and a moderate temperature (45 to 60 degrees Fahrenheit) for one to two weeks. This period allows the skins to thicken and minor wounds to heal, which helps prevent spoilage in storage.