Growing Onion in Kwale

Soil suitability analysis based on Kwale's nutrient profile

Quick answer

Yes — Kwale is well suited to Onion. Kwale's soil (pH 6.76, near-neutral) gives Onion a suitability score of 78/100. Match fertilizer to Kwale's nitrogen and phosphorus levels for the best result.

Kwale County is well suited to Onion, scoring 78/100 on ShambaIQ's soil-match model. Local soils average pH 6.76 — neutral and inside the 6–7 band Onion prefers, so no lime is usually required. The main gap is nitrogen, phosphorus, and potassium — measured at N 0.93 g/kg, P 9.8 mg/kg, K 131 mg/kg against this crop's high/high/medium demand — so the fertilizer plan below prioritises closing those deficits. The county's predominantly sandy loam soils suit Onion, which favours sandy loam. At current prices (about KES 70/kg) and a typical 6,000 kg/acre yield, a well-managed Onion crop here can gross roughly KES 420,000 per acre.

78Suitability score

Soil & climate match

FactorKwale soilOnion needsStatus
pH6.7667OK
Nitrogen0.93 g/kgmin 1.2 g/kgLow
Phosphorus9.8 mg/kgmin 20 mg/kgLow
Potassium131 mg/kgmin 150 mg/kgLow
Rainfall900 mm500–1,000 mmOK
Altitude200 m0–2,000 mOK

Planting calendar

Long Rains

Month 1
Nursery Preparation & Transplanting
Month 2
Top Dressing (CAN) & Weed Control
Month 3
Bulbing Stage & NPK 17:17:17 Application

Short Rains

Month 1
Nursery & Transplanting & Basal Fertilizer
Month 2
Top Dressing & Bulb Formation
Month 3
Harvesting & Curing

Dry Season

Month 1
Harvesting & Curing & Storage
Month 2
Land Preparation
Month 3
Nursery for next season

Top dressing guide

Product
CAN then NPK 17:17:17
Timing
Week 3–4 and at bulbing
Instruction
Apply at week 3–4 before bulbing then switch to NPK 17:17:17 at bulbing stage for bulb size and quality.
Bags per Acre
0.5

Recommended seed varieties

Red CreoleMedium/Highland
Simlaw Seeds · 90-120 days · 6–8 tons/acre
Popular red onion; good storage quality.
Bombay RedMedium
East Africa Seeds · 100-130 days · 5–7 tons/acre
Large bulb size; pungent flavor; high market value.

Economics

Market priceKES 70/kg
Expected yield in Kwale5,850 kg/acre
Estimated revenueKES 409,500/acre
Adjusted for Kwale's 78/100 suitability. Under ideal conditions Onion can reach 6,000 kg/acre (~KES 420,000/acre) — attainable here only after the climate and soil constraints below are addressed.

Preferred textureSandy Loam

Fertilizer prices

DAP
KES 3,500(6,500)
CAN
KES 2,875(4,500)
NPK 17:17:17
KES 3,275(5,600)
Urea
KES 3,500(5,500)
Lime
KES 1,500(1,800)

Green = subsidized · (Commercial) per 50kg bag