Growing Sweet Potato in Isiolo

Soil suitability analysis based on Isiolo's nutrient profile

Quick answer

Generally not ideal — Isiolo is poorly suited to Sweet Potato. Isiolo's soil (pH 7.83, alkaline) gives Sweet Potato a suitability score of 19/100. Match fertilizer to Isiolo's nitrogen and phosphorus levels for the best result.

Isiolo County is a challenging environment for Sweet Potato (soil-match score 19/100) and will need significant amendment before planting. At an average pH of 7.83 the soil sits above Sweet Potato's preferred 4.5–7 range, which can limit uptake of phosphorus and micronutrients. The main gap is nitrogen — measured at N 0.46 g/kg, P 37.4 mg/kg, K 395 mg/kg against this crop's low/medium/high demand — so the fertilizer plan below prioritises closing that deficit. The county's predominantly sandy soils suit Sweet Potato, which favours sandy loam. Isiolo receives approximately 350 mm/year — well below Sweet Potato's minimum of 600 mm — so supplemental irrigation would be essential for this crop. On ShambaIQ's soil-match model, Sweet Potato is the #55 soil match of the 106 crops we assess for Isiolo County. Sweet Potato's full potential is about 5,000 kg/acre (~KES 90,000/acre at KES 18/kg), but at Isiolo's 19/100 suitability a realistic target here is closer to 1,188 kg/acre (~KES 21,384/acre) unless the constraints above are addressed.

Better matched to Isiolo's soil: Sisal, Aloe Vera, and Green Grams — each scores higher on the same soil.

19Suitability score

Soil & climate match

FactorIsiolo soilSweet Potato needsStatus
pH7.834.57Adjust
Nitrogen0.46 g/kgmin 0.5 g/kgLow
Phosphorus37.4 mg/kgmin 12 mg/kgOK
Potassium395 mg/kgmin 200 mg/kgOK
Rainfall350 mm600–1,800 mmLow
Altitude900 m0–2,200 mOK

Planting calendar for Isiolo

Long Rains· MarchMay

March
Vine Cutting Planting & Basal Fertilizer
April
Weeding & Vine Management
May
Harvesting & Storage

Short Rains· OctoberDecemberMain season here

October
Vine Planting & Basal Fertilizer
November
Vine Trailing & Weeding
December
Harvesting

Dry Season· JanuaryMarch

January
Irrigation & Vine Planting
February
Weeding
March
Harvesting & Vine Multiplication

Top dressing guide

Product
None
Timing
None required
Instruction
Sweet potatoes rarely need top dressing. Excess N promotes vines over tubers.
Bags per acre in Isiolo
0

Isiolo's nitrogen reads 0.46 g/kg, but the rate stays at zero: Sweet Potato is not top-dressed, for the crop-specific reason above.

Seed varieties for Isiolo

Varieties suited to Isiolo's 900 m altitude and 350 mm annual rainfall — 1 of 5 sweet potato varieties we list.

KabodeMedium/Dryland
CIP/KALRO · 120-150 days · 3–4 tons/acre
Orange-fleshed; high Vitamin A; drought tolerant.

Economics

Market priceKES 18/kg
Expected yield in Isiolo1,188 kg/acre
Estimated revenueKES 21,384/acre
Adjusted for Isiolo's 19/100 suitability. Under ideal conditions Sweet Potato can reach 5,000 kg/acre (~KES 90,000/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