Sweet Potatoes or Yams
Ipomoea batatas. CONVOLVULACEAE.
Planting, Growing, and Harvesting
Sweet Potatoes or Yams
You’ll find everything you need to know to plant and grow sweet potatoes or yams in the accompanying table’s tabs:
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- How many sweet potatoes or yams to plant
- Growing conditions for sweet potatoes or yams
- When to plant sweet potatoes or yams
- How to plant sweet potatoes or yams
- Watering, fertilizing, and pruning sweet potatoes or yams
- Companion plantings for sweet potatoes or yams
- How to harvest, store, and use sweet potatoes or yams
Growing Sweet Potatoes or Yams
Sweet Potatoes and Garnet Yams are perennial warm-season tuberous vines of the Morning Glory family, while True Yams (Dioscorea spp.) are unrelated tuberous, tropical, vining plants of the Dioscorea family.
Unrelated to potato, sweet potatoes are tender tropical plants, to 4 ft. (1.2 m) tall, that bear pink to purple flowers and develop brown, red, or tan tubers reminiscent of elongated potatoes with firm gold or yellow flesh with a sweet flavor.
Sweet potatoes and yams usually are prepared in the kitchen by baking, boiling, frying, steaming, or mashing.
Sweet Potato or Yam Plant and Care Guide
How Much to Plant
Allow 5 plants per household member, yielding 20–25 sweet potatoes.
How to Plant
Seed-potato cuttings root in 10-18 days.
Average Climates: Sow tubers indoors in moist sand 6–8 weeks before soil is expected to warm to 60°F (16°C), maintaining a temperature of 80°F (27°C) for 3–4 weeks after planting, then reducing temperature to 70°F (21°C) when sprouts are 3–4 in. (75–100 mm) long, and hardening seedlings 10 days before transplanting.
Mild-Winter Climates: Plant seed-potato cuttings in full sun in spring, when soil first warms to 60–70°F (16–21°C) and is less than 85°F (29°C). Set out starts 2–3 in. (50–75 mm) deep, 12–18 in. (30–45 cm) apart, in rows raised 1 ft. (30 cm) high and 18 in. (45 cm) wide, 3–4 ft. (90–120 cm) apart, installing lattice or trellis supports at time of planting.
Best Conditions for Growth
65–95°F (18–35°C). Very heat tolerant. Best in long-season, subtropical and arid climates.
Soil Type and Fertility
Moist, well-drained, sandy soil. Fertility: Rich. 5.0–6.5 pH. Prepare soil at least 2 ft. (60 cm) deep.
Proper Care
Moderate. Keep evenly moist. Fertilize monthly during growth with acidic 5–10–10 fertilizer or supplement with garden sulfur. Cultivate. Avoid pruning or pinching vines. Train vines onto lattice or trellises. Disease resistant. Nematode susceptible.
Pairing Recommendations
Beets, parsnips, salsify, Malabar and New Zealand spinach, and turnips.
Maturity, Picking and Gathering
110–150 days. Harvest after 4 months, when test digging reveals fully developed potatoes, carefully digging with a garden fork, 24–30 in. (60–76 cm) from the stem, then gently pulling potatoes from central growth bud. Harvest promptly whenever vines wither or turn yellow, or upon frost.
How to Store and Preserve
For best fresh storage, cure in garden in direct sun for 3–4 hours, then place in a humid spot at 80–85°F (27–29°C) for 10–15 days after harvest. Fresh, stored in a dry, cool spot, 2–5 months. Eat sweet potatoes and yams baked, boiled, steamed, or mashed; they are rich in vitamin A and C.