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Script 32.1

Script

Think of sweet potatoes if you are looking for a crop that grows well in poor soils and fairly dry conditions, doesn’t need expensive fertilizers, and is tasty and nutritious.

Sweet potatoes are an excellent crop for small scale farmers. You can eat the leaves and the tubers. Together, the leaves and tubers of sweet potatoes are likely to produce more nutrients per square metre in poor soils than any other crop. The young leaves contain protein and vitamins. The tubers provide protein, starch, vitamin C, and vitamin A. The leaves are available throughout the long growing season; the tubers can be stored.

How to grow sweet potatoes

Sweet potatoes grow best in sandy soils with a bit of clay in them. But they will grow well in almost any soil as long as water doesn’t puddle in the soil after a rain. If the soil is not well drained, it can be worked into ridges or mounds. Some people add compost to the ridges and mounds before planting.

In the tropics, most people start sweet potatoes by planting vine cuttings that are 30 to 40 centimetres long. Plant the cuttings with at least 2/3 of their length underground, spacing them about a half metre apart. Cuttings from the tips of the vine are the best planting material. If you can’t get vine cuttings you can also plant the potato tubers directly in the soil.

For the first few weeks after planting, water the cuttings and make sure the soil doesn’t dry out. Sweet potatoes are hot weather crops. The hotter it is the faster they grow. Once the new plants get established, they can survive drought. Often when other crops are wilting in the heat, sweet potatoes are doing their best. As the vines grow and spread they choke out other weeds, creating their own living mulch so they don’t need much weeding after the first few weeks.

The sweet potato weevil is the main insect pest of sweet potatoes. One way of dealing with this problem is to rotate sweet potatoes with other crops from year to year. Or plant quick maturing varieties and harvest them as early as possible.

Once the sweet potato plants are established, the leaves can be harvested throughout the growing season. This will not affect the production of the tubers. Usually only the tender tips of the vine are harvested the parts where the stem snaps easily outward. Cook the leaves like any other green leafy vegetable.

When the tubers are big enough to harvest, dig them up and take them inside for storage right away. If they are in the sun for more than 30 minutes they can spoil. Store them in a cool, humid place. You can feed the vines to your animals.

The sweet potato is an easy-to-grow, adaptable crop. It tolerates some drought, requires little weeding, and little or no fertilizer. It has few insect or disease problems. And it is a nutritious food.

Information Sources

  • Thanks to Dr. Vince Machado, Department of Horticulture, University of Guelph, Ontario, Canada, for reviewing this script.
  • For more information about growing sweet potatoes, including fast maturing varieties, please contact:
    • H. Mendoza/Jennifer Woolfe International Potato Centre
      Apartado 5969
      Lima, Peru
    • Dr. Frank Martin Tropical Agricultural Research Station
      Box 70
      Mayaguez Puerto Rico
      00709
    • ECHO (Educational Concerns for Hunger Organization)
      17430 Durrance Road North
      Ft. Myers, Florida
      33917, U.S.A.
      Phone: (813) 534 5317
  • “Compost increases sweet potato yields in the Highlands”, Harvest, Vol. 8, No. 4, 1982, Publications Section, Department of Agriculture and Livestock, Port Moresby, Papua New Guinea.
  • Sweet potato planting material, IRETA publications No. 2, 1988, USP Alafua Campus, P.O. Private Bag, Apia, Western Samoa.
  • “Extension de la culture de patate douce” (Expansion of sweet potato cultivation), Entre Nous, Vol. 6, No. 2, May 1993, Rodale International, B.P. A 237, Thies, Senegal.
  • The production of sweet potatoes, Extension Guide No. 5, 1981, Agriculture Extension and Research Liaison Services, Ahmadu Bello University, Samaru, Zaria, Nigeria.
  • “Harvesting and utilization of sweet potato and cassava” Agroforestry Technical Information Kit, International Institute for Rural Reconstruction, Silang, Cavite, Philippines.
  • “Pest of sweet potato sweet potato weevil”, Entomology Bulletin No. 52 in Harvest, Vol. 14, No. 1 2, 1992, Publications Section, Department of Agriculture and Livestock, Port Moresby, Papua New Guinea.
  • “Sweet potatoes to help feed the world” in ECHO News, Vol. 12, No. 4, December 1989, ECHO, 17430 Durrance Rd., North Fort Myers, FL 33917 U.S.A.
  • Sweet potato, Crop Production Guide Series 2, Institute of Agricultural Research, IAR/MANRF, Njala, Sierra Leone.