A sprouted sweet potato provides the planting material, known as “slips,” which are the vine cuttings that grow from the storage root. Unlike common potatoes, which are true tubers, the sweet potato is a tuberous root, and planting the entire root is not the most efficient method for a high yield. The goal of sprouting a sweet potato is to generate numerous slips, which are the actual plant starts that will be transplanted into the garden.
Preparing the Slips for Planting
The first step after a sweet potato begins to sprout indoors is to separate the young shoots from the mother root. Slips can be grown by suspending the sweet potato half-submerged in water or, preferably, by laying the root in a tray of moist potting soil. The soil method encourages the slips to develop small roots while still attached, reducing the time needed for rooting later. Once the shoots reach about six to eight inches in length, they are ready to be harvested.
To harvest, carefully twist or cut the slip away from the sweet potato, ensuring the cut is made about an inch from the root surface to avoid transferring pathogens. The slips must then be rooted before planting in the garden. Placing the bottom few inches in a jar of water in a warm, bright location will encourage root development within a few days. The slips are ready for transplanting when they have formed a cluster of roots several inches long.
Establishing Ideal Growing Conditions
Sweet potatoes are a tropical crop, and successful growth depends on consistently warm temperatures, making proper timing crucial. Transplant the rooted slips only after all danger of frost has passed and both daytime and nighttime temperatures are reliably warm. The soil temperature must be a minimum of 60°F, but establishment is faster when the soil is consistently 65°F to 75°F. Using a soil thermometer to confirm this temperature is recommended.
The ideal planting location receives full sun, meaning at least six to ten hours of direct light daily. Sweet potatoes thrive in loose, well-drained, and slightly sandy loam soil, which allows for easy expansion of the developing roots. To improve drainage and warm the soil faster, especially in heavy clay regions, create raised mounds or ridges about eight inches high. Avoid adding high-nitrogen fertilizers, as this promotes excessive vine growth at the expense of root development.
Transplanting the Rooted Slips
Transplanting the rooted slips must be done carefully to prevent root damage and promote quick establishment. Plant the slips into the prepared mounds or ridges, spacing them approximately 12 to 18 inches apart within the row. Rows should be spaced three to four feet apart to accommodate the sprawling vines that develop throughout the season.
Each slip should be planted deep enough to bury at least 4 to 6 inches of the stem, ensuring a minimum of two to three leaf nodes are covered. Since sweet potatoes form along the buried nodes, deep planting encourages a higher yield. Ensure only the top cluster of leaves remains exposed above the soil line. Immediately after planting, water the slips thoroughly to settle the soil around the new roots and reduce transplant shock.
Post-Planting Care and Maintenance
Consistent moisture is important during the first week after transplanting to ensure the young slips establish themselves. Water the newly planted slips daily, aiming to keep the soil moist but not waterlogged. Once the plants have visibly started growing and producing new leaves, reduce the watering frequency to an average of one inch of water per week, especially during dry periods.
Keep the planting area free of weeds in the early stages, as young sweet potato plants cannot compete well for resources. Shallow cultivation is advised to avoid disturbing the developing roots near the surface. As the plant matures, the vines will spread and naturally shade out most weeds. The long vines should not be cut or pruned, as this redirects the plant’s energy away from tuber production and into healing the cut. Preventing the vines from rooting into the soil at the nodes will concentrate the plant’s resources into the main cluster of storage roots for a better harvest.