Growing Onion in Kisii

Soil suitability analysis based on Kisii's nutrient profile

Onion can be grown in Kisii County, but the soil scores 48/100 and needs targeted management to reach full potential. At an average pH of 5.21 the soil is moderately acidic, below Onion's preferred 6–7 range; agricultural lime will lift pH and unlock phosphorus the crop cannot otherwise access. The main gap is nitrogen and phosphorus — measured at N 1.09 g/kg, P 13.1 mg/kg, K 151 mg/kg against this crop's high/high/medium demand — so the fertilizer plan below prioritises closing those deficits. Onion prefers sandy loam soils, while Kisii is largely clay loam, so drainage and organic-matter management matter more here. Onion's full potential is about 6,000 kg/acre (~KES 420,000/acre at KES 70/kg), but at Kisii's 48/100 suitability a realistic target here is closer to 3,600 kg/acre (~KES 252,000/acre) unless the constraints above are addressed.