Sweet potatoes are grown by planting slips, which are small shoots sprouted from a mature tuber, rather than by planting seeds directly in the soil. These tropical perennials thrive in warm climates.
Many home gardeners attempt to plant store-bought tubers directly into the ground, but this often leads to rot or poor growth. Successful production requires specific preparation of these slips before planting.
This guide covers the essential steps for starting slips, preparing soil, managing growth, and harvesting tubers.
How to Grow Sweet Potato Slips from a Tuber
Sweet potato slips are produced by suspending a healthy, organic tuber in water or burying it in moist soil until sprouts emerge. Each tuber can produce ten to twenty individual slips over several weeks.
To start the process, select a firm, disease-free sweet potato. Place the bottom third of the tuber in a jar of water, using toothpicks to hold it in place. Keep the jar in a warm, sunny location. Within a few weeks, green shoots will appear. Once these shoots reach four to six inches in length, carefully twist them off the main tuber. Place these slips in a separate container of water until they develop their own white root systems.
| Stage | Action | Duration |
|---|---|---|
| Sprouting | Suspend tuber in water | 3 to 5 weeks |
| Rooting | Place slips in water | 1 to 2 weeks |
| Hardening | Acclimate to outdoor air | 3 to 7 days |
What Soil Conditions Do Sweet Potatoes Require?
Sweet potatoes require loose, well-draining, sandy loam soil with a pH between 5.8 and 6.2 to produce high-quality tubers. Compacted or heavy clay soils often result in stunted, misshapen, or cracked roots.
Before planting, work the soil to a depth of at least ten inches to ensure the roots can expand easily. Incorporate organic matter like compost to improve drainage and nutrient availability. Avoid adding excessive nitrogen, as this promotes lush vine growth at the expense of tuber development. Raised beds are often preferred because they provide better drainage and allow the soil to warm up faster in the spring.
When Is the Best Time to Plant Sweet Potatoes?
Sweet potatoes should be planted outdoors only after the soil has warmed significantly and all danger of frost has passed. They require a long, frost-free growing season of at least 100 to 120 days.
Wait until the soil temperature reaches at least 65 degrees Fahrenheit before moving slips into the garden. Planting too early in cold soil can cause the slips to rot or stop growing entirely. If the local growing season is short, start the slips indoors well in advance to ensure they are ready for transplanting the moment the weather turns consistently warm.
How Much Space Do Sweet Potato Vines Need?
Sweet potato vines are vigorous growers that require significant space, typically needing 12 to 18 inches of distance between each plant. Rows should be spaced three to four feet apart to allow for vine spread.
Because the vines can grow several feet long, they often cover the entire garden bed. Some growers use trellises to keep the vines contained, though this does not increase tuber yield. Ensure the area remains free of weeds during the first month of growth. Once the vines cover the ground, they naturally shade out most competing weeds.
How Much Water Do Sweet Potatoes Need?
Sweet potatoes need consistent moisture during the first few weeks after transplanting to establish strong root systems. Once established, they are relatively drought-tolerant, though they still require regular water for optimal tuber size.
Provide about one inch of water per week throughout the growing season. Reduce watering significantly about three to four weeks before the expected harvest date. This reduction helps the skins of the tubers toughen, which improves their storage life. Avoid overwatering during the final month, as excess moisture can lead to root rot or splitting.
| Growth Phase | Water Requirement | Goal |
|---|---|---|
| Establishment | High | Root development |
| Mid-Season | Moderate | Tuber expansion |
| Pre-Harvest | Low | Skin toughening |
How to Manage Common Pests and Diseases
The most common issues for sweet potatoes include wireworms, sweet potato weevils, and fungal diseases like scurf or wilt. Maintaining healthy soil and rotating crops annually are the most effective ways to prevent these problems.
- Wireworms: These pests tunnel into the roots. Use light, sandy soil and avoid planting in areas that were recently sod or grass.
- Weevils: These insects are common in warm climates. Use certified disease-free slips and destroy any infested tubers immediately.
- Fungal Wilts: These diseases cause the vines to yellow and collapse. Ensure proper drainage and avoid planting in areas where other morning glory family plants recently grew.
When and How to Harvest Sweet Potatoes
Sweet potatoes are ready for harvest when the leaves begin to yellow or immediately after the first light frost kills the vines. Carefully dig around the perimeter of the plant to avoid damaging the tubers.
Use a garden fork to lift the soil and tubers gently from below. Avoid using a shovel, as it can easily slice through the roots. After lifting, allow the tubers to dry in a shaded, well-ventilated area for several hours. Do not wash the tubers until you are ready to use them, as moisture promotes decay.
How to Cure Sweet Potatoes for Storage
Curing is the essential process of holding sweet potatoes in a warm, humid environment to heal skin wounds and convert starches into sugars. This process significantly extends the shelf life of the harvest.
Place the harvested tubers in a single layer in a room with a temperature of 80 to 85 degrees Fahrenheit and high humidity. Keep them there for seven to ten days. After curing, move the tubers to a cool, dark storage location with good airflow. They should be stored at 55 to 60 degrees Fahrenheit. Never store them in a refrigerator, as cold temperatures damage the internal structure of the root.
How many slips can one sweet potato produce?
A single healthy sweet potato can produce between ten and twenty slips if kept in warm, moist conditions. The number depends on the size of the tuber and the duration of the sprouting period.
Can sweet potatoes grow in containers?
Sweet potatoes grow well in containers if the pot is at least twelve inches deep and wide. Use a light, well-draining potting mix and ensure the container has adequate drainage holes to prevent water from pooling around the roots.
Do sweet potatoes need full sun?
Sweet potatoes require at least six to eight hours of direct sunlight every day for maximum production. They are heat-loving plants that thrive in high temperatures and will not produce well in shaded garden areas.
Why are my sweet potatoes small?
Small tubers often result from a short growing season, poor soil quality, or excessive nitrogen fertilizer. Ensure the plants have enough time to mature and that the soil is loose enough for the roots to expand fully.
Can you eat the leaves of a sweet potato plant?
The leaves of the sweet potato plant are edible and are often used in cooked dishes. Only harvest a few leaves from each plant to ensure the vine remains healthy enough to continue supporting tuber growth.
Conclusion:
Successful sweet potato production relies on a few specific environmental and timing factors.
- Start with healthy slips sprouted from a clean tuber.
- Plant in loose, well-draining soil after the ground warms.
- Provide consistent water during the early growth phase.
- Cure the harvested tubers to ensure long-term storage success.
