Growing Watermelon in Kiambu

Soil suitability analysis based on Kiambu's nutrient profile

Quick answer

Generally not ideal — Kiambu is poorly suited to Watermelon. Kiambu's soil (pH 5.28, strongly acidic) gives Watermelon a suitability score of 38/100. Apply agricultural lime before planting to unlock phosphorus and lift the score.

Kiambu County is a challenging environment for Watermelon (soil-match score 38/100) and will need significant amendment before planting. At an average pH of 5.28 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 (1.01 g/kg), phosphorus (13.7 mg/kg) and potassium (169 mg/kg) all meet Watermelon's requirements, so a maintenance fertilizer programme is enough. Watermelon prefers sandy soils, while Kiambu is largely clay, so drainage and organic-matter management matter more here. Watermelon's full potential is about 15,000 kg/acre (~KES 150,000/acre at KES 10/kg), but at Kiambu's 38/100 suitability a realistic target here is closer to 7,125 kg/acre (~KES 71,250/acre) unless the constraints above are addressed.

38Suitability score

Soil & climate match

FactorKiambu soilWatermelon needsStatus
pH5.2867.5Adjust
Nitrogen1.01 g/kgmin 0.8 g/kgOK
Phosphorus13.7 mg/kgmin 12 mg/kgOK
Potassium169 mg/kgmin 150 mg/kgOK
Rainfall1,100 mm300–700 mmHigh
Altitude1,700 m0–1,500 mHigh

Top dressing guide

Product
CAN
Timing
Week 3-4 after transplanting
Instruction
Apply at vine development stage. Stop nitrogen at flowering — excess N promotes leaves over fruits.
Bags per Acre
0.5

Recommended seed varieties

Sugar BabyDryland/Medium
Simlaw Seeds · 75-90 days · 5–7.5 tons/acre
Small round fruits; sweet red flesh; popular local market.
Charleston GreyMedium
Simlaw Seeds · 80-95 days · 6–9 tons/acre
Large oblong fruits; excellent taste; high yield.

Economics

Market priceKES 10/kg
Expected yield in Kiambu7,125 kg/acre
Estimated revenueKES 71,250/acre
Adjusted for Kiambu's 38/100 suitability. Under ideal conditions Watermelon can reach 15,000 kg/acre (~KES 150,000/acre) — attainable here only after the climate and soil constraints below are addressed.

Preferred textureSandy

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