Growing Onion in Tharaka Nithi

Soil suitability analysis based on Tharaka Nithi's nutrient profile

Tharaka Nithi County is a solid choice for Onion, with a soil-match score of 65/100. At an average pH of 4.99 the soil is strongly 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 phosphorus — measured at N 1.23 g/kg, P 19.6 mg/kg, K 211 mg/kg against this crop's high/high/medium demand — so the fertilizer plan below prioritises closing that deficit. The county's predominantly sandy loam soils suit Onion, which favours sandy loam. At current prices (about KES 45/kg) and a typical 3,500 kg/acre yield, a well-managed Onion crop here can gross roughly KES 157,500 per acre.