Growing Onion in Trans Nzoia

Soil suitability analysis based on Trans Nzoia's nutrient profile

Quick answer

Yes — Trans Nzoia is well suited to Onion. Trans Nzoia's soil (pH 5.93, slightly acidic) gives Onion a suitability score of 79/100. Match fertilizer to Trans Nzoia's nitrogen and phosphorus levels for the best result.

Trans Nzoia County is well suited to Onion, scoring 79/100 on ShambaIQ's soil-match model. At an average pH of 5.93 the soil is slightly acidic to near-neutral, below Onion's preferred 6–7 range; agricultural lime will lift pH and unlock phosphorus the crop cannot otherwise access. Nitrogen (1.68 g/kg), phosphorus (27.3 mg/kg) and potassium (213 mg/kg) all meet Onion's requirements, so a maintenance fertilizer programme is enough. Onion prefers sandy loam soils, while Trans Nzoia is largely clay loam, so drainage and organic-matter management matter more here. On ShambaIQ's soil-match model, Onion is the #61 soil match of the 106 crops we assess for Trans Nzoia County. 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.

79Suitability score

Soil & climate match

FactorTrans Nzoia soilOnion needsStatus
pH5.9367Adjust
Nitrogen1.68 g/kgmin 1.2 g/kgOK
Phosphorus27.3 mg/kgmin 20 mg/kgOK
Potassium213 mg/kgmin 150 mg/kgOK
Rainfall1,200 mm500–1,000 mmHigh
Altitude1,900 m0–2,000 mOK

Planting calendar for Trans Nzoia

Long Rains· MarchMayMain season here

March
Nursery Preparation & Transplanting
April
Top Dressing (CAN) & Weed Control
May
Bulbing Stage & NPK 17:17:17 Application

Short Rains· AugustOctober

August
Nursery & Transplanting & Basal Fertilizer
September
Top Dressing & Bulb Formation
October
Harvesting & Curing

Dry Season· JanuaryMarch

January
Harvesting & Curing & Storage
February
Land Preparation
March
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 in Trans Nzoia
0.5

Trans Nzoia's nitrogen (1.68 g/kg) already meets Onion's 1.2 g/kg requirement, so this is a maintenance rate.

Seed varieties for Trans Nzoia

Varieties suited to Trans Nzoia's 1,900 m altitude and 1,200 mm annual rainfall — 2 of 2 onion varieties we list.

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 Trans Nzoia5,925 kg/acre
Estimated revenueKES 414,750/acre
Adjusted for Trans Nzoia's 79/100 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(5,700)
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