Sweet Potato


Sweet Potato locally known as Viazi vya tamu (Swahili); Makwasi (Kikamba); Mapwoni (Luyia); Ngwaci (Kikuyu) are perennial vines, with one main season whose roots are eaten either boiled or roasted alone or with other foods such as milk, porridge, soups or meat. Young leaves are used as vegetable. The sweet potato vines are a useful and nutritious fodder crop, especially in the dry season. Some varieties are especially suited for this, producing abundant tops.


Varieties SPK 004/013, Kemb10/20/23, KSP11/20, Simama, NASPOT 1
Seed Rate 3-5 plants per metre square
Fertilizer Rate 35 kg P (phosphorus)/ha., 95 to 140 kg N (nitrogen)/ha
Planting Spacing 15 x 20 cm plant to plant and 90 – 120 cm between ridges
Husbandry After cultivation, the land is usually prepared into ridges. Ridges should be oriented along contours on sloping land, to maximize rain water infiltration and minimize erosion. Ridges are typically about 30-45 cm high. Planting is through vine cuttings or storage roots. Sweet potato responds well to fertilisation, particularly if the land has been continuously cropped.
Pest & Diseases Pest Name Symptoms Control
Sweet potato weevil The root have dark wounds. Using repellants like Lantana Leaves
Maturity Duration 4 months
Climatic Conditions Sweet potato is grown at altitudes 0 – 3000 m. Its growth is maximum at temperatures above 25°C. Its sun-loving crop and grows well in an annual rainfall of 600-1600 mm. The optimum soil pH for sweet potato is 5.6 – 6.6.
Harvesting Progressive harvesting (piece-meal harvesting) is common using spade or hoe. It is generally recommended to harvest within 4 months to prevent weevil damage.
Post Harvest and Storage Sweet potatoes are kept in a cool dry place. Avoid injuring them. Remove any injured piece from the rest.
Growing Regions Central, Rift Valley, Western and upper eastern
Expected yields 10-25 tons per hectare


Processing Shred into Chips and Crisps.Dried and Ground into Flour.


Place Sweet Potatoes are marketed locally.
Price Kshs. 30 – 40 per kg


Products and Uses Root is eaten Boiled or Roasted. Shoots eaten as vegetablesVines and leaves are used as fodder.
Nutritional value – per 100 g / % Daily Values The young leafy shoots, eaten as a green vegetable, are high in protein, b-carotene, thiamine (vitamin B1), riboflavin (B2), folic acid and ascorbic acid. The root is rich in Sugar and Vitamin A.



Income Per Hectare: Kshs 300,000 (10,000kgs * 30/-)Cost per Hectare: Kshs. 120,000 (40% of Income).

NET:    Kshs. 280,000 (60% of Income).

Break Even Yield (Where Cost=Income): = 4000kgs per hectare.

Income Frequency: Twice per year.

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