Sweet potatoes (Ipomoea batatas) are among the most productive food crops per square meter on the planet. A single vine can yield 1 to 2 kg of tubers with minimal fertilizer, and the leaves themselves are edible and nutrient-dense. From backyard gardeners in the United States to smallholder farmers in Nigeria, the world’s largest producer, the same principles apply. This guide covers everything you need to plant, grow and harvest sweet potatoes successfully in 2026.
1. Sweet potato basics
- Botanical family: Convolvulaceae. Not related to regular potatoes despite the name.
- Origin: Central and South America. Now grown in over 100 countries.
- Cycle: 90 to 170 days depending on variety and climate.
- Climate: warm-season crop. Requires at least 4 months of frost-free weather. Optimal daytime temperature 21–27 °C (70–80 °F).
- Yield potential: 15 to 30 tonnes per hectare in well-managed fields; 1 to 3 kg per vine in home gardens.
Note: in the US and UK, « sweet potato » and « yam » are often used interchangeably in supermarkets, but true yams (Dioscorea spp.) are a different species and require a different itinerary, not covered here.
2. Choose your variety
Sweet potato varieties fall into three groups by flesh color:
- Orange-fleshed (Beauregard, Covington, Jewel, Kabode): high in beta-carotene (vitamin A precursor). The standard for market and export.
- White or cream-fleshed (O’Henry, Bonita): drier, less sweet. Popular in traditional African and Asian cuisine.
- Purple-fleshed (Stokes Purple, Okinawan): rich in anthocyanins. Growing niche market for health-conscious consumers.
For African growers, the CIP (International Potato Center) has released a number of high-yielding, disease-resistant orange-fleshed varieties as part of the biofortified sweet potato program, critically important for combating vitamin A deficiency across the continent.
3. When to plant sweet potatoes
Temperate climate (US, UK, Europe)
- Plant slips 2 to 4 weeks after the last frost date, when soil temperature reaches 18 °C (65 °F).
- Zones 3–5: late May to early June.
- Zones 6–7: mid to late May.
- Zones 8–10: April onwards.
Tropical climate (Sub-Saharan Africa, Southeast Asia, Caribbean)
- West Africa (Nigeria, Ghana, Cameroon): plant at the start of the rainy season, April to June depending on the zone.
- East Africa (Kenya, Uganda, Tanzania): two seasons possible, long rains (March-May) and short rains (October-December).
- Sweet potatoes tolerate drought better than most other tuber crops, making them a resilience crop in areas with irregular rainfall.
4. Prepare your planting material: slips
Sweet potatoes are grown from slips,rooted shoots from a mature tuber, not from seed.
Producing your own slips
- Select firm, healthy tubers with no bruises or soft spots.
- Place in a shallow container of moist sand or half-buried in warm soil.
- Keep at 25–30 °C in bright light.
- After 3 to 6 weeks, shoots emerge from the tuber. Once they reach 15–20 cm with 4 to 6 leaves, gently twist them off.
- Place each slip in water for a few days until small roots appear, then transplant.
One healthy tuber can produce 20 to 50 slips.
Buying slips
Certified virus-free slips are the safest option for commercial production. In the US, reputable nurseries ship slips in late spring. In Sub-Saharan Africa, agricultural research stations, CIP partners and vetted multipliers are the recommended sources, avoid random market slips that may carry sweet potato feathery mottle virus (SPFMV) or sweet potato chlorotic stunt virus (SPCSV).
5. Prepare the soil
- Soil type: light, sandy loam is ideal. Heavy clay produces misshapen tubers.
- pH: 5.5 to 6.5.
- Depth: deep loose soil, at least 30 cm.
- Drainage: essential. Sweet potatoes rot in waterlogged soil.
- Ridging: form ridges 20 to 30 cm high. Ridging is the single most important soil preparation step, it improves drainage, warms the soil, and makes harvest easier.
Fertilization at planting
- Apply 5 to 10 tonnes per hectare of well-decomposed compost or manure.
- Sweet potatoes need moderate potassium and low nitrogen. Avoid high-nitrogen fertilizers,they promote vine growth at the expense of tubers.
- Suggested formulation: NPK 5-10-20 or similar low-N, high-K formula at 300 to 500 kg per hectare.
6. Plant your slips
- Spacing: 30 cm between plants on the ridge, 90 cm between ridges, approximately 37,000 plants per hectare.
- Planting depth: bury the lower half of the slip (about 10 cm) at a slight angle. Leave 2 to 3 leaves above soil.
- Best time: late afternoon or on a cloudy day.
- Water thoroughly immediately after planting.
7. Ongoing care
Watering
Sweet potatoes need consistent moisture during the first 40 days, then tolerate drought reasonably well. Water requirement: 500 to 700 mm over the growing cycle. Stop watering 2 to 3 weeks before harvest to allow tubers to firm up.
Weeding
Weed at 2 to 4 weeks after planting and again at 6 to 8 weeks. Once the vines close the canopy, they suppress weeds naturally.
Vine training
Some growers lift and reposition vines periodically to prevent adventitious rooting at the nodes, which diverts energy from the main tubers. This is optional but can boost yield 10 to 15 %.
Pests and diseases
- Sweet potato weevil (Cylas spp.): the most damaging pest globally. Use resistant varieties, rotate crops, hill the ridges thoroughly, harvest on time.
- Viruses (SPVD complex): transmitted by whiteflies and infected planting material. Prevention starts with clean slips.
- Root rot: caused by poor drainage. Ensure high ridges and adequate spacing.
8. Harvest
- Sweet potatoes are ready 90 to 170 days after planting, depending on variety.
- Signs of maturity: leaves start to yellow; test-dig a few plants to check tuber size.
- Harvest by carefully lifting with a fork or hoe. Avoid nicking the skins, damaged tubers do not store well.
- Cure freshly harvested tubers in a warm humid environment (29–32 °C, 85–90 % humidity) for 4 to 7 days. This heals wounds and sweetens the flesh.
- Storage: 13–16 °C at 85 % humidity. Properly cured tubers keep for 6 to 10 months.
9. Yield and profitability
Well-managed sweet potato yields:
- Home garden: 15 to 30 kg per 10 m² bed.
- Smallholder African farm: 8 to 15 tonnes per hectare in traditional systems, 20 to 30 t/ha with improved varieties and inputs.
- Commercial US/UK production: 20 to 30 t/ha routinely, top farms above 40 t/ha.
Sweet potatoes are increasingly recognized as a strategic crop for food security and export. If you are planning a commercial project, our turnkey agricultural projects team supports feasibility studies, planning and setup across sub-Saharan Africa.
Article by the Jogoo Agriculture agronomy team. Recommendations should be adapted to your climate, variety and locally registered inputs.
Frequently asked questions
How long does it take to grow sweet potatoes?
Sweet potatoes take 90 to 170 days from planting to harvest, depending on the variety. Short-cycle varieties like Beauregard mature in about 90 to 100 days, while long-cycle varieties require 130 to 170 days. In tropical climates with two rainy seasons, growers can achieve two crops per year.
Can I grow sweet potatoes from a store-bought sweet potato?
Yes. Select firm, healthy tubers with no bruises, avoid those treated with sprout inhibitors, and place them in moist sand or half-buried in warm soil at 25–30 °C. After 3 to 6 weeks, shoots emerge that you can twist off, root in water, and transplant. One tuber produces 20 to 50 slips.
What is the best fertilizer for sweet potatoes?
Sweet potatoes need moderate potassium and low nitrogen. High-nitrogen fertilizers promote vine growth at the expense of tubers. Apply 5 to 10 tonnes per hectare of well-decomposed compost or manure at planting, plus 300 to 500 kg per hectare of a low-N high-K formulation such as NPK 5-10-20 or equivalent.
How do you know when sweet potatoes are ready to harvest?
Signs of maturity include yellowing leaves and vine dieback, typically 90 to 170 days after planting depending on variety. Test-dig a few plants to check tuber size. Harvest before the first frost in temperate climates or before the end of the growing season in tropical zones.
How do you store sweet potatoes after harvest?
Cure freshly harvested sweet potatoes in a warm humid environment (29–32 °C, 85–90 % humidity) for 4 to 7 days to heal wounds and sweeten the flesh. Then store at 13–16 °C with 85 % humidity in a dark, well-ventilated space. Properly cured tubers keep for 6 to 10 months.