Planting and Growing Sweet Potatoes

The Complete Guide to Growing Sweet Potatoes: How to Grow Sweet Potatoes from Slips to Harvest

Sweet potatoes (Ipomoea batatas) are a nutritious, delicious, and rewarding crop to grow in home gardens. Often confused with yams, sweet potatoes are actually a member of the morning glory family and are considered tuberous roots, not true tubers like traditional potatoes. Known for their vibrant orange flesh (though varieties with purple, red, and white flesh also exist), sweet potatoes are rich in vitamins, fiber, and antioxidants.

Whether you're a beginner gardener or an experienced grower, this complete guide will walk you through every step of growing sweet potatoes—from starting slips to harvesting and curing your crop. We'll also answer the most frequently asked questions about how to grow sweet potatoes, including how to grow them in containers and increase your yield.

Understanding Sweet Potatoes vs. Yams

Before diving into cultivation, it's essential to understand the difference between sweet potatoes and yams. While the names are often used interchangeably in the U.S., they're entirely different plants:

• Sweet Potatoes: Smooth-skinned with orange, red, white, or purple flesh. Part of the morning glory family.

• Yams: Belong to the lily family, typically have rough, bark-like skin, and can grow very large (up to 7 feet). Rare in U.S. grocery stores.

How to Grow Sweet Potato Slips

Sweet potatoes aren’t grown from seeds or seedlings. Instead, they grow from slips, which are sprouts that develop from mature sweet potatoes.

Starting Slips from Organic Sweet Potatoes

To start growing slips from sweet potatoes, begin about 8–12 weeks before your target planting date:

1. Choose a sweet potato: Use organic sweet potatoes for planting, as conventional ones are often treated with sprout inhibitors.

2. Prepare your medium: Use a tray filled halfway with potting soil for sweet potatoes, Quickroot, or perlite. While perlite is an option, it doesn't yield slips as quickly.

3. Position the sweet potato: Lay it horizontally in the tray and cover halfway with moist soil.

4. Use heat and light: Place the tray on a heating mat and under a grow light to encourage sprouting.

5. Keep soil moist: Avoid overwatering, but don’t let the soil dry out.

In about 4–6 weeks, sprouts will appear. Allow each sprout to grow 6 inches long before cutting it off the mother potato.

Rooting the Slips

1. Remove lower leaves from the slips.

2. Place in a jar or glass of water.

3. Position on a heating mat or under a grow light.

4. Change water weekly.

Roots should form in a few days. Once roots are 2–3 inches long, your slips are ready for planting.

When and How to Plant Sweet Potato Slips

Best Time to Plant

The best month to plant sweet potatoes depends on your climate, but typically it's 2–3 weeks after your last frost, once the soil reaches 65°F or warmer.

Soil and Site Preparation

• Best soil for sweet potatoes: Loose, well-drained, and slightly acidic (around pH 6.5).

• If you have clay soil, amend it with compost or grow in raised beds.

• For container growing, use a sweet potato potting mix or a blend of loamy soil, sand, and compost.

Try the Beauregard Sweet Potato Slips, Bayou Belle, Red Japanese, or Covington varieties, all available from Grow Organic.

Planting Sweet Potatoes

• Space slips 12–18 inches apart.

• Bury each slip deep enough that only the top leaves are exposed.

• Water thoroughly after planting.

To prevent the vines from rooting along their length (which diverts energy from tuber formation), grow them on a trellis or use mulch to keep vines above ground.

How to Grow Sweet Potatoes in Containers

Container gardening is a great option if you have limited space:

• Use a 15–20 gallon container, such as a Smart Pot.

• Fill with best soil mix for sweet potatoes, ensuring it’s loose and drains well.

• Plant one slip per container.

• Place in full sun and keep soil moist (not soggy).

Learn more about container-friendly varieties and slips at Grow Organic's sweet potato section.

Watering and Fertilizing

• Deep water, allowing soil to slightly dry out between waterings.

• Avoid soggy soil to prevent root rot.

• Use a phosphorus-rich fertilizer if your soil is deficient. Avoid high nitrogen fertilizers which encourage vine growth but reduce tuber yield.

For more balanced soil, try organic options available at Grow Organic.

Harvesting, Curing & Storage

When to Harvest

• Sweet potatoes mature in 90–120 days.

• Harvest before the first fall frost, once leaves begin to yellow.

• Loosen soil with a fork, then gently dig by hand to avoid damage.

Curing

• Cure in a warm (80°F), humid space out of direct sunlight for 10–14 days.

• This helps convert starches to sugars and heals minor damage.

Storage

• Store cured sweet potatoes in a dry, cool (55–65°F) area.

• Do not refrigerate.

• Properly stored sweet potatoes can last 4–7 months.

Conclusion

Growing sweet potatoes is a fulfilling gardening endeavor, whether you plant them in raised beds or containers. From preparing slips to curing your harvest, the key is patience, warmth, and good soil.

With varieties like Beauregard and Red Japanese available at Grow Organic, you can enjoy a diverse and productive harvest. Once you've mastered how to grow sweet potatoes, you’ll find them a staple in your garden year after year.

FAQs About Growing Sweet Potatoes

• Can I grow a sweet potato from a sweet potato?
  • Yes, you can grow sweet potato from seed by producing slips from a mature, untreated organic sweet potato. These slips are the sprouts used to propagate new plants.
• How do you grow sweet potatoes for beginners?
  • Start with organic slips, plant in warm, loose soil after frost, and water consistently. Raised beds or large containers with sweet potato potting mix make it easier for new gardeners.
• How long does it take to grow a sweet potato?
  • Sweet potatoes typically take 90–120 days to mature, depending on the variety and growing conditions.
• Can sweet potatoes be grown in pots?
  • Absolutely. Use a 15–20 gallon container with well-drained potting soil for sweet potatoes. Only one slip per container is recommended for best yield.
• What is the best month to plant sweet potatoes?
  • Late spring to early summer, typically 2–3 weeks after your region’s last frost when soil temperatures reach 65°F or higher.
• What is the best fertilizer for sweet potatoes?
  • Use a low-nitrogen, high-phosphorus fertilizer to encourage root growth over vine production. Avoid excessive nitrogen.
• How to increase the yield of sweet potatoes?
  • Use loose, fertile, well-drained soil
  • Water deeply but avoid soggy soil
  • Avoid letting vines root along their length
  • Use phosphorus-rich fertilizer only when needed
• How to make sweet potatoes sweeter?
  • Curing sweet potatoes for 10–14 days in warm, humid conditions allows starches to convert to sugars, enhancing sweetness.
• Do sweet potato vines need support?
  • They don’t require support but training them on a trellis can prevent rooting along the vine, which preserves energy for the main tuber.
• Can I grow sweet potatoes indoors?
  • Yes, you can start slips indoors and even grow in containers if you have ample sunlight or grow lights.