Onion farming guide — Kenya
Soil requirements, top counties, seed varieties, fertilizer plan & economics
To grow onion in Kenya, aim for soil pH 6–7 (sandy loam soils); the best-suited counties are Nakuru, Narok, Baringo, Elgeyo Marakwet, Nairobi. Apply DAP or NPK at planting and top-dress with CAN then NPK 17:17:17 at Week 3–4 and at bulbing. A well-managed crop yields about 6,000 kg/acre (~KES 420,000 gross per acre).
Interested in starting or scaling onion farming in Kenya? This comprehensive guide maps out the optimal soil requirements (such as target pH ranges), the most suitable counties for growing onion, certified seed varieties, seasonal fertilizer guidelines, and a detailed per-acre production budget to set you up for a successful harvest.
Soil requirements
Growing conditions for Onion
Onion does best with 500–1,000 mm of rainfall a year at 0–2,000 m above sea level. In drier areas, irrigation or water harvesting closes the gap; outside the altitude band, growth and yields drop.
Optimizing soil and fertilizers for Onion in Kenya
To achieve maximum yields when farming onion in Kenya, managing soil suitability is crucial. This crop performs best within a soil pH range of 6 to 7. Soils that fall outside this range can lock out essential macro and micro-nutrients, leading to stunted growth or crop failure. For acidic soils, applying dolomitic or calcitic agricultural lime is recommended at least 30 days before planting to normalize acidity.
Fertilizer application should be calibrated based on the crop’s nutrient demands. Onion has a high nitrogen requirement, high phosphorus requirement, and medium potassium demand. Using certified seed varieties suited for your specific altitude and rainfall pattern, combined with a precise basal and top-dressing program (such as applying CAN then NPK 17:17:17 at Week 3–4 and at bulbing), ensures high crop quality and protects your overall farm investment.
How to grow onion in Kenya
- 1Prepare the soilEnsure soil pH is between 6 and 7. Preferred texture: Sandy Loam. Apply agricultural lime if your pH is below 6, ideally 30 days before planting.
- 2Plant at the right timePlant onion during Long Rains (Nursery Preparation & Transplanting–Bulbing Stage & NPK 17:17:17 Application) or Short Rains (Nursery & Transplanting & Basal Fertilizer–Harvesting & Curing) or Dry Season (Harvesting & Curing & Storage–Nursery for next season), timed to the start of the rains.
- 3Apply basal fertilizerOnion needs high nitrogen, high phosphorus, and medium potassium. Apply a balanced basal fertilizer such as DAP or NPK at planting.
- 4Top-dressAt Week 3–4 and at bulbing, apply 0.5 bag(s) per acre of CAN then NPK 17:17:17. Apply at week 3–4 before bulbing then switch to NPK 17:17:17 at bulbing stage for bulb size and quality.
- 5Monitor and harvestScout regularly for pests and disease. Expected yield is about 6,000 kg/acre at roughly KES 70/kg.
Best counties for Onion
Challenging counties for Onion
These counties may need soil amendments for Onion
Certified seed varieties
Planting calendar
Long Rains
Short Rains
Dry Season
Economics
Top dressing
Apply at week 3–4 before bulbing then switch to NPK 17:17:17 at bulbing stage for bulb size and quality.
Fertilizer prices
Subsidized price / 50kg bag
Frequently asked questions about onion farming in Kenya
What soil pH is best for growing onion in Kenya?
Onion grows best in soil with a pH of 6 to 7. If your soil is more acidic than pH 6, apply agricultural lime about 30 days before planting to raise the pH and free up nutrients. The preferred soil texture is sandy loam.
Which counties are best for onion farming in Kenya?
By soil suitability, the top counties for onion are Nakuru, Narok, Baringo, Elgeyo Marakwet, Nairobi. A full ranking of all 47 counties, each with a suitability score, is shown above.
What fertilizer does onion need?
Onion has high nitrogen, high phosphorus, and medium potassium requirements. Apply a balanced basal fertilizer such as DAP or NPK at planting, then top-dress with 0.5 bag(s) per acre of CAN then NPK 17:17:17 at Week 3–4 and at bulbing.
When should I plant onion in Kenya?
Plant onion during Long Rains (Nursery Preparation & Transplanting to Bulbing Stage & NPK 17:17:17 Application) or Short Rains (Nursery & Transplanting & Basal Fertilizer to Harvesting & Curing) or Dry Season (Harvesting & Curing & Storage to Nursery for next season), timed to the start of the rains in your area.
How much can I earn from onion per acre in Kenya?
Onion yields about 6,000 kg per acre. At a market price of roughly KES 70/kg, that is around KES 420,000 per acre in gross revenue, before input and labour costs.
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