Sweet potato is either planted in mounds or on ridges using vine cuttings. Vines are the mature stems and are taken from the shoot.
A good vine cutting should be about 1ft long or six nodes and should be disease-free.
When mounds are used, they should not exceed one metre in height and diameter. The size of the mound, however, varies with the type of soil.
In soils that are prone to drying, small mounds are used; big mounds in such a case are over exposed to sunshine and they dry out fast.
The number of vines used vary, as small mounds will take a few vines and the big mounds accommodate more vines.
Planting is mostly done by hands, but you can plant sweet potatoes using forked sticks in some cases.
Vines for planting should be picked and allowed to wilt in the shade to ensure that the vines do not break during planting as fresh vines are brittle.
The vines also root easily and ensure faster establishment of the crop in the soil.
Growth Requirement
It grows best at an average temperature of 24°C, with abundant sunshine and warm nights.
Annual rainfalls of 750-1,000mm are considered most suitable. Sweet potatoes are grown on a variety of soils, but well-drained, light and medium-textured soils with a pH range of 4.5-7.0 are more favourable for the crop.
A soil test will give a farmer the right pH. They can be grown in poor soils with little fertiliser.
Sweet potatoes can be produced in low and high altitudes as long as the soils are fertile.
Common potato varieties
Sweet potato varieties grown in Uganda include Tanzania, Tororo 3, new kawogo and kakamega. The orange-fleshed varieties include NASPOT8, 11, 12, 13 and NAROSPOT1, 2, 3 and 5.
These have good storage root, high dry matter content, high level of beta-carotene and resistant to sweet potato virus.
It is also grown as smoother crop in control of striga and organic manure addition, as well as erosion control.
So far, NARO has released 27 varieties of the crop. You can also differentiate sweet potatoes by their skin and flesh colour.
The most predominant skin colours are white and pinkish, while the flesh colours are mostly yellow and orange.
Pests, diseases and control
The most common pest is weevils; others are caterpillars and grasshoppers.
The diseases include sweet potato virus disease and altarnaria, affecting the leaves and stems and fusarium wilt.
Farmers are advised to use resistant varieties such as the orange-fleshed varieties and they should avoid spreading susceptible seedlings.
Controlling pests, diseases
- Crop rotation helps to break the cycle of pests, hence preventing them.
- Closed season: This also helps pests from spreading since there is no host plants to harbour them.
Spray using soil insecticides and pesticides to control sweet potato pests like cypermethrin to control wire worms.
