Growing Pyrethrum in Machakos

Soil suitability analysis based on Machakos's nutrient profile

Machakos County is a challenging environment for Pyrethrum (soil-match score 16/100) and will need significant amendment before planting. At an average pH of 7.03 the soil sits above Pyrethrum's preferred 5–6.5 range, which can limit uptake of phosphorus and micronutrients. Nitrogen (0.82 g/kg), phosphorus (31.4 mg/kg) and potassium (338 mg/kg) all meet Pyrethrum's requirements, so a maintenance fertilizer programme is enough. The county's predominantly sandy loam soils suit Pyrethrum, which favours loam. At 1100 m, the county sits below Pyrethrum's preferred altitude range (1800–3000 m), which limits yield potential due to heat stress. Pyrethrum's full potential is about 500 kg/acre (~KES 140,000/acre at KES 280/kg), but at Machakos's 16/100 suitability a realistic target here is closer to 100 kg/acre (~KES 28,000/acre) unless the constraints above are addressed.