Growing Sweet Potato in Kwale
Soil suitability analysis based on Kwale's nutrient profile
Kwale County is a solid choice for Sweet Potato, with a soil-match score of 72/100. Local soils average pH 6.76 — neutral and inside the 4.5–7 band Sweet Potato prefers, so no lime is usually required. The main gap is phosphorus and potassium — measured at N 0.93 g/kg, P 9.8 mg/kg, K 131 mg/kg against this crop's low/medium/high demand — so the fertilizer plan below prioritises closing those deficits. The county's predominantly sandy loam soils suit Sweet Potato, which favours sandy loam. At current prices (about KES 18/kg) and a typical 5,000 kg/acre yield, a well-managed Sweet Potato crop here can gross roughly KES 90,000 per acre.
Suitability score
Soil & climate match
| Factor | Kwale soil | Sweet Potato needs | Status |
|---|---|---|---|
| pH | 6.76 | 4.5–7 | OK |
| Nitrogen | 0.93 g/kg | min 0.5 g/kg | OK |
| Phosphorus | 9.8 mg/kg | min 12 mg/kg | Low |
| Potassium | 131 mg/kg | min 200 mg/kg | Low |
| Rainfall | 900 mm | 600–1,800 mm | OK |
| Altitude | 200 m | 0–2,200 m | OK |
Planting calendar
Long Rains
Month 1
Vine Cutting Planting & Basal Fertilizer
Month 2
Weeding & Vine Management
Month 3
Harvesting & Storage
Short Rains
Month 1
Vine Planting & Basal Fertilizer
Month 2
Vine Trailing & Weeding
Month 3
Harvesting
Dry Season
Month 1
Irrigation & Vine Planting
Month 2
Weeding
Month 3
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
0
Recommended seed varieties
KabodeMedium/Dryland
CIP/KALRO · 120-150 days · 3–4 tons/acre
Orange-fleshed; high Vitamin A; drought tolerant.
Kenspot 5Medium/Highland
KALRO · 90-120 days · 4–5 tons/acre
Purple-skinned; excellent taste; good market demand.
VitamuMedium/Highland
KALRO · 120-150 days · 3.5–4.5 tons/acre
Orange-fleshed; dual purpose grain and fodder; KEPHIS certified; 1200-1800m; released 2015.
Kenspot-1Highland
KARI Njoro · 120-150 days · 3.5–4.5 tons/acre
Orange-fleshed; high beta-carotene; suited to 1700-2300m; released 2013.
Kenspot-3Highland
KARI Njoro · 120-150 days · 4–5 tons/acre
White-fleshed; high dry matter; good storability; 1900-2300m cold highland adapted; released 2013.
Economics
Market priceKES 18/kg
Expected yield in Kwale4,500 kg/acre
Estimated revenueKES 81,000/acre
Adjusted for Kwale's 72/100 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(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