Bulb Onion Farming Program, bulb onions are among the most profitable horticultural crops in Kenya. However, achieving high yields requires a well-coordinated farming program that covers seed selection, land preparation, fertilization, irrigation, and pest control. This guide outlines a practical onion production schedule designed to help farmers produce uniform bulbs, reduce losses, and improve market quality.

1. Land Preparation

Soil Requirements

• Well-drained loamy soil
• High organic matter content
• Preferred pH: 6.0 – 6.8

Preparation Steps

Begin with deep ploughing to break compacted soil layers. Afterward, harrow the field to achieve a fine tilth that supports root penetration. In addition, apply 8–10 tons of well-decomposed manure per acre to improve soil fertility. Raised or flat beds can then be prepared depending on the irrigation method used.

2. Seed Selection & Nursery Management

Recommended Varieties

Farmers can choose from high-quality varieties such as:

• Red Creole
• Texas Grano
• Bombay Red
• Neptune F1, Red Coach F1, and other hybrid types

These varieties offer good yield potential and adaptability.

Nursery Preparation

Start by sterilizing topsoil and mixing it with sand to improve aeration. Next, treat the nursery bed with an approved fungicide to prevent damping-off. Sow seeds lightly, apply a thin mulch, and water using a fine sprinkler. Within 6–8 weeks, seedlings will be ready for transplanting.

3. Transplanting

Steps

Transplant seedlings when they reach pencil thickness. To minimize shock, water the nursery before uprooting. During transplanting, maintain a spacing of 30 cm between rows and 8–10 cm within rows. Working during early morning or late afternoon helps seedlings establish more easily.

Pre-plant Inputs

Before transplanting, incorporate a starter fertilizer such as DAP or any phosphorus-rich alternative. Additionally, the use of termiticides in termite-prone areas helps protect young seedlings. Pre-emergent herbicides may also be applied around the beds (not on the crop) to reduce early weed pressure.

4. Fertilizer Application Program (Per Acre)

Week 1–3: Establishment Phase

Apply NPK 17:17:17 at 50–70 kg per acre. This encourages strong root development and early vegetative growth.

Week 4–6: Bulb Initiation Phase

Switch to CAN (Calcium Ammonium Nitrate) at 50 kg per acre. The nitrogen improves leaf growth, which directly influences bulb size.

Week 7–10: Bulbing Phase

Use NPK 10:26:26 or Potassium Nitrate at 30–50 kg per acre. These formulations enhance bulb formation and improve firmness.

Micronutrients

Apply foliar feeds containing calcium, magnesium, and sulfur every 10–14 days. Moreover, avoid excessive nitrogen during late growth, as it delays maturity and reduces storage quality.

5. Irrigation Management

Consistent moisture is essential during early growth. For best results, adopt drip irrigation, which ensures uniform water distribution and reduces disease pressure. As bulbing begins, gradually reduce irrigation to prevent splitting. Stop watering 2–3 weeks before harvesting to promote proper curing and a longer shelf life.

6. Weed Management

Onions have shallow roots, making them highly sensitive to weed competition. Therefore, apply pre-emergent herbicides before transplanting and use selective herbicides during crop development. When hand weeding, work carefully to avoid damaging the root system.

7. Pest & Disease Management

Common Pests

• Thrips
• Cutworms
• Onion maggots

Common Diseases

• Purple blotch
• Downey mildew
• Neck rot

Protection Schedule

Stage	Treatment	Purpose
Early growth	Preventive fungicide	Controls damping-off diseases
Continuous	Insecticide rotation	Manages thrips and maggots
Mid–Late stage	Systemic fungicides	Reduces mildew and purple blotch

Furthermore, rotating pesticides helps prevent resistance and maintains effectiveness.

8. Harvesting & Curing

When to Harvest

Harvest when the tops fall over and turn yellow. Bulbs should be firm with dry outer skins.

Post-Harvest Processing

Lift bulbs and sun-dry them for 3–5 days. After that, move them to a shaded, well-ventilated area for 2–3 weeks of curing. Proper curing enhances storage quality. Finally, store onions in ventilated crates or nets to maintain airflow.

Key Takeaways

• A fine, fertile seedbed improves bulb formation
• Strong nursery practices reduce early losses
• Balanced nutrition and timely irrigation are critical
• Weed and pest management must be consistent
• Proper curing ensures longer storage life

A structured bulb onion farming program enables farmers to achieve uniform bulbs and higher marketable yields. By following each stage carefully, farmers can reduce losses and improve crop quality. Agriguard Agrovet remains committed to supplying reliable seeds, fertilizers, herbicides, and crop protection solutions that support successful onion production.