How to Grow Sweet Potatoes from Slips to Storage

Introduction to Sweet Potato Cultivation

Sweet potatoes (Ipomoea batatas) rank among the most rewarding crops for home gardeners, producing abundant harvests of nutrient-dense tubers from modest garden space. Unlike regular potatoes, sweet potatoes thrive in warm climates and offer exceptional versatility in culinary uses. This resilient plant grows well in USDA hardiness zones 9-11 as a perennial and in cooler zones (3-8) as an annual summer crop. With proper techniques, gardeners can harvest dozens of nutrient-rich tubers from just a few plants.

Beyond their impressive yield potential, sweet potatoes offer significant health benefits and multiple garden uses. The tender young shoots serve as nutritious salad greens, while mature tubers provide high levels of beta-carotene, vitamin C, and fiber. Their vigorous vines create lush ground cover that helps suppress weeds, making them an ideal choice for permaculture designs and edible landscaping.

Choosing Varieties for Your Garden

Selecting the appropriate variety significantly impacts success with sweet potatoes. Consider these popular types and their characteristics:

• Beauregard: Fast-maturing (90 days) with copper skin and deep orange flesh. Adapts well to various soils
• Covington: Uniform tubers with rose skin and moist orange flesh. Excellent disease resistance
• Jewel: Classic orange flesh with high beta-carotene content. Heavy yields on shorter vines
• O'Henry: Unique white flesh with cream-colored skin. Sweet, moist texture resembling potatoes
• Purple/Murasaki: Vibrant purple flesh packed with anthocyanins. Higher antioxidant content

For northern gardens with shorter seasons, prioritize early-maturing varieties like Georgia Jet or the compact California Gold. Gardeners seeking novelty might explore multicolored varieties increasingly available through specialty seed suppliers.

Starting Sweet Potato Slips at Home

Sweet potatoes propagate from plant shoots called slips, not seeds. Creating your own slips saves money and ensures plant health:

1. Select healthy tubers: Choose organic sweet potatoes free of blemishes (store-bought work)
2. Suspend tubers in water: Insert toothpicks halfway into tubers and suspend in jars with the tapered end submerged
3. Provide warmth and light: Place containers in bright, indirect light at 75-85°F
4. Monitor root development Roots emerge in 2-4 weeks; leafy shoots (slips) follow
5. Harvest slips: When slips reach 6-8 inches with several leaves, twist them off
6. Root cuttings in water: Place slip stems in water for 7-10 days until new roots develop

For direct planting, start tubers in trays of moist potting mix instead of water. Lift and separate rooted slips after 4-6 weeks. Avoid using soil contaminated with pests from previous sweet potato crops to prevent disease transmission.

Soil Preparation and Planting Techniques

Sweet potatoes require loose, well-drained soil with slightly acidic pH (5.8-6.2). Two weeks before planting:

• Work compost 8-10 inches deep (1-2 inches per square foot)
• Raise beds 8-12 inches tall to improve drainage
• Avoid nitrogen-rich fertilizers that promote vines over tubers
• Cover soil with black plastic fabric to warm it if temperatures are below 65°F

Planting stage:

1. Plant slips outdoors when soil exceeds 65°F and frost danger passes
2. Space plants 12-18 inches apart in rows 3 feet apart
3. Dig holes 4-6 inches deep and gently set roots pointing downward
4. Bury the entire root system plus 1-2 inches of stiff stem
5. Water thoroughly with diluted seaweed fertilizer to reduce transplant shock

Planting tips: Always transplant slips on overcast days or evenings. If unexpected cold threatens, cover plants with frost blankets until temperatures stabilize.

Cultivation and Care Requirements

Sweet potatoes thrive with consistent care during their 3-5 month growing period:

Watering: Provide 1 inch of water weekly through deep weekly soakings rather than frequent light sprinkles. Reduce watering 3-4 weeks before harvest.

Weed Management: Eliminate weeds while vines are small. Once vines spread (5-6 feet), they suppress weeds naturally. Avoid deep hoeing that disturbs shallow roots.

Fertilizing Apply balanced organic fertilizer (5-10-10) at planting and again at 6 weeks. Excess nitrogen causes excessive foliage with undersized tubers.

Pruning/Vine Training: For confined spaces, gently guide vines away from other plants. Optional pruning of ends encourages branching but isn't critical for yields.

Apply natural pest deterrents: Spray neem oil weekly if sweet potato weevils are endemic in your region. Install row covers until flowering prevents insect damage.

Container Gardening Techniques

Sweet potatoes adapt remarkably well to containers, making them perfect for small-space gardeners:

• Container Specs: Choose 15-20 gallon containers with drainage holes
• Soil Mix: Blend equal parts compost, coconut coir, and perlite
• Planting Density: Plant 1-2 slips per container
• Water Management: Use self-watering containers or water when top 1 inch dries
• Vine Support: Train vines up trellises or allow them to cascade
• Temperature Control: Move containers indoors during unexpected cold

High-yield varieties for containers include Vardaman (compact bush type) and Porto Ricos. Container-grown tubers often develop cleaner and more uniform shapes than ground-grown counterparts.

Organic Pest and Disease Prevention

Preventative measures reduce sweet potato susceptibility to common issues:

Integrated pest management tips: Attract predatory insects with companion plants like nasturtiums. Inspect leaf undersides weekly. Keep gardens weed-free to discourage pest habitats.

Harvesting: Timing and Techniques

Sweet potatoes need precise timing for peak flavor and storage potential. Harvest timing cues:

• 90-120 days after planting (check variety maturity)
• Leaf yellowing after first light frost (enhances sweetness)
• Drier fall weather before soil temperatures drop below 55°F

Harvest steps:

1. Cut vines at soil level 1-2 days before digging
2. Lift tubers carefully using digging forks 10 inches from stems
3. Minimize tuber injury - even small bruises reduce storage life
4. Leave tubers in field for 2-3 hours maximum (protect from hot sun)

Post-harvest treatment: Immediately cure undamaged tubers at 85°F with 85-90% humidity for 10-14 days. Never wash tubers before curing - gently brush off soil after process completes.

Curing and Storage Solutions

The curing process heals minor wounds and converts starches to sugars, significantly improving texture and sweetness. Ideal curing environment:

• Temperature: 80-85°F
• Humidity: 85-90% (place tubers in breathable boxes covered with damp towels)
• Duration: 10-14 days

Storage conditions:

• Temperature stability: 55-60°F
• Moderate humidity (60-70%)
• Minimal light to prevent solanine development
• Regular tuber inspection every 4 weeks

Storage methods: Store cured tubers in newspaper-lined cardboard boxes or baskets in closet interiors. Avoid refrigerating sweet potatoes. Properly cured varieties keep 3-6 months indoors.

Propagating Next Year's Plants

Preserve desirable genetics and save money by overwintering tubers:

• Select medium-sized tubers from best-performing plants
• Cure normally and store in separate boxes labeled with variety
• Check monthly for shriveling; mist storage containers lightly if needed
• Commence slip production 10-12 weeks before planting date

Regeneration protocol: Replant your original stock tubers for 2-3 years maximum before introducing new virus-free stock, as sweet potato viruses accumulate over generations. Exchange slips with neighbors to maintain genetic diversity.

Frequently Asked Questions

How many sweet potatoes per plant?
Expect 3-8 pounds from in-ground plants (5-10 tubers) and 2-4 pounds from containers.

Why no tubers form?
Cold stress, excess nitrogen, planting too deep, or overcrowding causes poor tuber set.

Edible leaves?
Yes! Harvest young leaves for salads or sauté like spinach. Prep method affects oxalate content.

Green patches on tubers?
Sunlight exposure causes chlorophyll development. Peel affected areas before cooking as chlorophyll indicates increased solanine levels.

Sources

• University of Minnesota Extension: Growing Sweet Potatoes
• University of Florida IFAS: Sweet Potatoes in the Garden
• North Carolina State Extension: Sweet Potato Production Guide
• The Old Farmer's Almanac: Growing Sweet Potatoes