Open-Field Tomato Production (90 Days)
A comprehensive tomato farming guide for open-field production covering variety selection, nursery management, transplanting, irrigation, integrated pest management, and post-harvest handling. Optimised for Kenya's highland and midland growing conditions.
Dr. Grace Wanjiku
MSc Horticulture, Jomo Kenyatta University of Agriculture & Technology
11 years experience
Dr. Grace Wanjiku specialises in high-value horticultural crops including tomatoes, capsicum, French beans, and avocado. She has worked with the Ministry of Agriculture and several NGOs to scale greenhouse adoption among smallholders in Central Kenya. Her tomato and vegetable programs have been adopted by over 1,200 farmers in Kiambu, Murang'a, and Meru.
Sample Schedule (First 2 Weeks)
Site & Variety Selection
Choose a well-drained site with loam soil, pH 5.5–7.0. Select a high-yielding, disease-resistant variety: Kilele F1, Rambo F1, or Anna F1 are popular in Kenya. Avoid low-lying waterlogged areas.
Soil Testing
Collect composite soil sample from 5 points across the plot. Send to Kenya Soil Survey laboratory or use KARI soil testing kits. Results guide fertiliser application.
Nursery Bed Preparation
Prepare raised nursery beds (1 m wide × any length, 15 cm high). Mix top soil, compost, and sand (2:1:1). Treat beds with Dithane M-45 to prevent damping-off disease.
Seed Sowing
Sow tomato seeds in rows 10 cm apart, 1 cm deep. Cover with thin layer of compost. Mulch with dry grass. Water gently twice daily. Use 25 g seed per 1 m² bed.
Nursery Irrigation
Water nursery beds morning and evening using a watering can with a rose head. Avoid overwatering — soil should be moist, not waterlogged. Check for germination from Day 7.
Land Preparation Begin
Start deep ploughing main field to 30 cm depth. Break clods. If possible, subsoil compact layers. Remove crop debris and root them out.
Nursery Germination Check
Germination should be 80%+ by Day 7. Thin to 2 cm spacing if overcrowded. Shade seedlings during peak afternoon sun with grass thatch or 50% shade net.
Basal Fertiliser Application
Apply farmyard manure (10 t/ha) or compost (5 t/ha) and incorporate into soil during secondary tillage. Add DAP 50 kg/ha as basal dressing during final land prep.
Nursery Hardening Begins
Gradually reduce nursery irrigation and increase sun exposure to harden seedlings. This reduces transplanting shock. Continue for 7 days before transplanting.
Bed Formation
Form raised beds (15–20 cm high, 1 m wide) with 50 cm pathways. Mark planting holes at 60 cm within row and 75 cm between rows (plant population ~22,000/ha).
Irrigation System Setup
Install drip irrigation lines along beds (emitter spacing 30 cm). Test for uniform flow. Drip irrigation reduces disease risk from leaf wetness and saves 40% water vs furrow.
Transplanting Day
Transplant seedlings (18–25 days old, 4–5 true leaves) in the evening or on a cloudy day. Water planting holes before inserting seedling. Apply 50 ml diluted starter fertiliser per hole.
Transplant Check
Check all transplanted seedlings for wilting. Replace any that failed to establish. Water gently. Apply mulch (dry grass or black polythene) around plants to conserve moisture.
Post-Transplant Fertiliser
Apply CAN at 50 kg/ha as top dress at planting holes, keeping 10 cm away from stems. This supplies nitrogen for early vegetative growth.
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