Growing Green Grams in Kiambu

Soil suitability analysis based on Kiambu's nutrient profile

Quick answer

Possible but challenging — Kiambu is only marginally suited to Green Grams. Kiambu's soil (pH 5.28, strongly acidic) gives Green Grams a suitability score of 49/100. Apply agricultural lime before planting to unlock phosphorus and lift the score.

Green Grams can be grown in Kiambu County, but the soil scores 49/100 and needs targeted management to reach full potential. At an average pH of 5.28 the soil is moderately acidic, below Green Grams's preferred 5.5–8 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 Green Grams's requirements, so a maintenance fertilizer programme is enough. Green Grams prefers sandy loam soils, while Kiambu is largely clay, so drainage and organic-matter management matter more here. Green Grams's full potential is about 400 kg/acre (~KES 48,000/acre at KES 120/kg), but at Kiambu's 49/100 suitability a realistic target here is closer to 245 kg/acre (~KES 29,400/acre) unless the constraints above are addressed.

49Suitability score

Soil & climate match

FactorKiambu soilGreen Grams needsStatus
pH5.285.58Adjust
Nitrogen1.01 g/kgmin 0.5 g/kgOK
Phosphorus13.7 mg/kgmin 6 mg/kgOK
Potassium169 mg/kgmin 100 mg/kgOK
Rainfall1,100 mm250–700 mmHigh
Altitude1,700 m0–1,800 mOK

Top dressing guide

Product
None
Timing
None required
Instruction
Green Grams fix atmospheric Nitrogen. No top dressing needed. Inoculate seed with Rhizobium before planting.
Bags per Acre
0

Recommended seed varieties

N26Dryland/Medium
KALRO · 60-65 days · 3-5 bags/acre
Early maturing; tolerant to drought; popular in eastern Kenya.
KS 20Medium
KALRO · 65-75 days · 4-6 bags/acre
High yielding; good seed quality; resistant to yellow mosaic virus.

Economics

Market priceKES 120/kg
Expected yield in Kiambu245 kg/acre
Estimated revenueKES 29,400/acre
Adjusted for Kiambu's 49/100 suitability. Under ideal conditions Green Grams can reach 400 kg/acre (~KES 48,000/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