Growing Sweet Potato in Garissa

Soil suitability analysis based on Garissa's nutrient profile

Garissa County is a challenging environment for Sweet Potato (soil-match score 10/100) and will need significant amendment before planting. At an average pH of 7.96 the soil sits above Sweet Potato's preferred 4.5–7 range, which can limit uptake of phosphorus and micronutrients. Nitrogen (0.61 g/kg), phosphorus (37.7 mg/kg) and potassium (407 mg/kg) all meet Sweet Potato's requirements, so a maintenance fertilizer programme is enough. The county's predominantly sandy soils suit Sweet Potato, which favours sandy loam. Garissa receives approximately 250 mm/year — well below Sweet Potato's minimum of 600 mm — so supplemental irrigation would be essential for this crop. At current prices (about KES 18/kg) and a typical 3,500 kg/acre yield, a well-managed Sweet Potato crop here can gross roughly KES 63,000 per acre.