Growing Watermelon in Nyandarua

Soil suitability analysis based on Nyandarua's nutrient profile

Nyandarua County is a challenging environment for Watermelon (soil-match score 21/100) and will need significant amendment before planting. At an average pH of 5.38 the soil is moderately acidic, below Watermelon's preferred 6–7.5 range; agricultural lime will lift pH and unlock phosphorus the crop cannot otherwise access. Nitrogen (1.28 g/kg), phosphorus (14 mg/kg) and potassium (166 mg/kg) all meet Watermelon's requirements, so a maintenance fertilizer programme is enough. Watermelon prefers sandy soils, while Nyandarua is largely clay, so drainage and organic-matter management matter more here. At 2300 m, the county sits above Watermelon's preferred altitude ceiling of 1500 m, where frost risk and cold nights reduce the crop's productivity. Watermelon's full potential is about 15,000 kg/acre (~KES 150,000/acre at KES 10/kg), but at Nyandarua's 21/100 suitability a realistic target here is closer to 3,938 kg/acre (~KES 39,380/acre) unless the constraints above are addressed.