Potatoes are grown through vegetative propagation, using the tuber rather than botanical seeds. The small indentations, known as “eyes,” are buds containing the genetic information to grow a new plant. Each planted piece of the tuber will grow into a clone of the parent, making this a simple method for home gardeners. This approach avoids the genetic variability associated with true potato seeds.
Preparing Potatoes for Planting
Before planting, “chitting” encourages sprout development and gives the plant a head start. Place tubers in a single layer, with the end containing the most eyes facing upward, in a bright, cool, and frost-free location. The ideal temperature is between 45°F and 55°F (7°C and 12°C).
Chitting aims to produce short, stocky, dark green or purple sprouts, which takes approximately four to six weeks. If the potato is larger than a chicken egg, cut it into pieces about 1.5 to 2 ounces, ensuring each section retains at least two healthy eyes. Smaller tubers can be planted whole.
After cutting, the pieces must be cured for one to three days in a dry, airy place away from direct sunlight. This curing allows the cut surface to form a protective, leathery callus. This sealing prevents the exposed flesh from rotting or succumbing to soil-borne diseases.
Selecting the Growing Environment
Potatoes perform best in full sun, requiring at least six to eight hours of direct light daily. The soil should be loose, well-draining, and slightly acidic, ideally with a pH range between 5.3 and 6.0. Dense or waterlogged soil can lead to tuber rot and poor development.
Gardeners can plant in traditional ground rows, raised beds, or containers like grow bags or buckets. Containers must have adequate drainage holes and be at least 18 inches deep to allow space for hilling. Use a specialized soil mix in containers, typically a 50/50 blend of soilless potting mix and quality compost.
This lightweight, non-compacting mixture provides the loose structure and consistent moisture retention necessary for proper tuber expansion. High-quality compost supplies the nutrients needed for initial growth, establishing a healthy environment.
Step-by-Step Planting and Essential Hilling
Once the prepared pieces are ready, plant them approximately four to six inches deep, with the eyes pointing upward, and cover them with a few inches of soil. For optimal yield in rows, space the pieces about 10 to 12 inches apart. Container planting requires similar spacing based on the vessel size.
Hilling is fundamental because new tubers develop along underground stems, called stolons, not directly from the roots. Hilling involves gradually mounding soil or organic material, like straw, around the growing stems. This encourages the formation of more stolons, leading to a greater potato yield.
The first hilling should occur when green stems emerge and reach six to eight inches tall. Add new material to cover the stems, leaving only the uppermost foliage exposed. Repeat this process whenever the plant grows another six to eight inches, building a final hill 12 to 18 inches tall.
Hilling also protects developing tubers from sunlight. Tubers exposed to light turn green and produce solanine, a natural toxin that makes them unsafe to eat. Consistent moisture is required throughout the growing cycle, with plants needing about one inch of water per week, particularly during tuber formation.
Knowing When and How to Harvest and Store
Harvest time depends on the desired size and maturity, categorized as “new” or “main crop.” New potatoes are small, tender, and thin-skinned; they can be harvested after the plants flower, usually 10 to 12 weeks after planting. This early harvest involves carefully digging around the plant perimeter to remove a few tubers while allowing the main plant to continue growing.
For a full harvest of main crop potatoes, wait until the plant’s foliage naturally begins to yellow, wither, and die back. This cue, known as senescence, signals that the plant has finished producing energy and the tuber skins have thickened for storage. Once the foliage has died completely, leave the tubers in the ground for an additional 10 days to allow the skin to fully set and mature.
After digging, potatoes need a short curing period before long-term storage. Cure them in a dark, well-ventilated area at 50°F to 60°F (10°C to 15°C) with high humidity for one to two weeks. This step allows minor cuts or bruises to heal, reducing the risk of rot. Optimal long-term storage is a dark, cool space, such as a root cellar or basement, at 38°F and 45°F (3°C and 8°C).