This archive report was first published on 21 August 2021.
Kenya is one of the largest potato producers in Africa, with the crop being the second most important food crop after maize. According to the National Potato Council of Kenya (NPCK), potatoes are popular and marketable, making them a lucrative business for farmers.
Victor Kariuki, an Irish potato farmer from Molo, shared his expertise on production for commercial purposes. He emphasized the importance of selecting the right site for potato farming, stating that land should not have been under any other potato family crops or tomatoes, capsicum, eggplant for at least four seasons to avoid soil-borne diseases and pests.
When selecting a site, Kariuki advises against poorly drained or rocky soils. He recommends ploughing the land, digging the field thoroughly to remove weeds and break lumps of soil for good air circulation and to allow tubers to grow. Mixing in well-rotted manure and ensuring the soil surface is smooth are also crucial steps in preparing the land for potato farming.
Seed selection is another critical aspect of potato farming. Kariuki recommends buying certified seed tubers from agents approved by the Kenya Plant Health Inspectorate Service (Kephis). The seed tubers should have four to five small sprouts growing out.
Planting potatoes in rows is essential, with furrows 75cm apart and 25cm deep. Kariuki advises applying Diammonium phosphate (DAP) at the rate of 200kg per acre at planting. On acidic soils with a pH level of below 5.5, use Monoammonium Phosphate (MAP) at the same rate.
Management of the crop is also crucial, with weeding starting once the potatoes have grown above the soil. When the potato plants are between 15 to 25cm tall, heap soil around the roots to give more space for the tubers to grow big and reduce chances of turning green.
Common pests and diseases to watch out for include Early Blight, late blight, brown rot, potato tuber moth, potato leaf rolls virus, and potato viruses. Kariuki advises spraying fungicides on affected crops when you notice the first spots, and for effective control, spray the underside of the leaves.
Harvesting potatoes is a critical step, with the farmer making sure the skin of tubers has hardened. Kariuki recommends letting plant tops dry naturally or cutting the top of plants two weeks before harvest to harden the skin. Harvesting in dry weather is also essential for quicker drying of tubers and healing of skin wounds.
Irish potatoes take an average of 70 to 120 days to mature, depending on the variety. According to Kariuki, an acre can produce an average of 7,700kg, with a kilo of potatoes going for Sh27 according to NPCK. A farmer could earn Sh207,900 in three months.
