Growing Tree Tomato (Tamarillo) in Isiolo

Soil suitability analysis based on Isiolo's nutrient profile

Quick answer

Generally not ideal — Isiolo is poorly suited to Tree Tomato (Tamarillo). Isiolo's soil (pH 7.83, alkaline) gives Tree Tomato (Tamarillo) a suitability score of 4/100. Match fertilizer to Isiolo's nitrogen and phosphorus levels for the best result.

Isiolo County is a challenging environment for Tree Tomato (Tamarillo) (soil-match score 4/100) and will need significant amendment before planting. At an average pH of 7.83 the soil sits above Tree Tomato (Tamarillo)'s preferred 5.8–7 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 high/high/high demand — so the fertilizer plan below prioritises closing that deficit. Tree Tomato (Tamarillo) prefers loam soils, while Isiolo is largely sandy, so drainage and organic-matter management matter more here. Isiolo receives approximately 350 mm/year — well below Tree Tomato (Tamarillo)'s minimum of 800 mm — so supplemental irrigation would be essential for this crop. On ShambaIQ's soil-match model, Tree Tomato (Tamarillo) is the #99 soil match of the 106 crops we assess for Isiolo County. Tree Tomato (Tamarillo)'s full potential is about 8,000 kg/acre (~KES 640,000/acre at KES 80/kg), but at Isiolo's 4/100 suitability a realistic target here is closer to 400 kg/acre (~KES 32,000/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.

4Suitability score

Soil & climate match

FactorIsiolo soilTree Tomato (Tamarillo) needsStatus
pH7.835.87Adjust
Nitrogen0.46 g/kgmin 1.2 g/kgLow
Phosphorus37.4 mg/kgmin 20 mg/kgOK
Potassium395 mg/kgmin 200 mg/kgOK
Rainfall350 mm800–1,800 mmLow
Altitude900 m1,500–2,800 mLow

Planting calendar for Isiolo

Long Rains· MarchMay

March
Transplanting & Basal
April
Staking & Top Dressing
May
Fruit Development

Short Rains· OctoberDecemberMain season here

October
Transplanting & Basal
November
Staking & Top Dressing
December
Fruit Development

Top dressing guide

Product
CAN
Timing
Every 3 months
Instruction
Perennial — ring-apply around the drip line each quarter. Add NPK at flowering.
Bags per acre in Isiolo
0.750.5

Isiolo's nitrogen (0.46 g/kg) is 38% of the 1.2 g/kg Tree Tomato (Tamarillo) needs, so the standard 0.5 bags/acre is raised to 0.75. Split it across two applications to limit leaching.

Economics

Market priceKES 80/kg
Expected yield in Isiolo400 kg/acre
Estimated revenueKES 32,000/acre
Adjusted for Isiolo's 4/100 suitability. Under ideal conditions Tree Tomato (Tamarillo) can reach 8,000 kg/acre (~KES 640,000/acre) — attainable here only after the climate and soil constraints below are addressed.

Preferred textureLoam

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