The Best Fertilizer for Onions in Kenya:A 2025 Complete Guide

Growing high-quality bulb onions in Kenya requires proper fertilization, good soil, hybrid seeds, and consistent irrigation. The right fertilizer application at each growth stage ensures strong vegetative growth, healthy bulb formation, and the highest yield.

In this guide, we’ll break down the best fertilizers for onions in Kenya. We will explain their correct application techniques. You’ll also get expert tips to boost your onion farming success.

1. Preparing the Soil: The Foundation for High Onion Yields

Use Well-Decomposed Farmyard Manure

Before planting, apply farmyard manure and mix it shallowly into the soil. Why?

• Improves soil fertility
• Enhances water retention (important for shallow-rooted onions)
• Provides organic nutrients for strong early growth

Pro Tip: Use 10-15 tons of manure per acre. Mix it with soil two weeks before transplanting. This ensures better results.

Read Also:The Best Time to Plant Onions in Kenya (2025 Updated Guide)

2. Early Growth Stage (10 Days After Transplanting)

Fertilizer: Di-ammonium Phosphate (DAP) – 100kg per Acre

Many farmers apply DAP at planting, but the best time to apply it is 10 days after transplanting. By this time, the young seedlings have developed root hairs, allowing them to absorb nutrients efficiently.

Benefits of DAP for Onions:

• High phosphorus content promotes strong root development
• Boosts vegetative growth for healthier plants
• Prevents early-stage nutrient deficiencies

Application Tip: Apply DAP on wet soil to prevent root scorching. Avoid direct contact with young plants.

Supplementary Foliar Fertilizers:

To further support early growth, spray foliar fertilizers like:

• Optimizer
• HyRICH-N
• Stim Pure

These foliar feeds help strengthen seedlings and improve nutrient absorption.

3. Bulb Formation Stage (Second Month After Transplanting)

Fertilizer: NPK 17:17:17 – 100kg per Acre

As onions enter the second month, bulb formation begins. Applying NPK 17:17:17 provides a balanced mix of nutrients:

• Phosphorus (P) – Supports bulb development
• Potassium (K) – Enhances bulb size and quality
• Nitrogen (N) – Promotes healthy leaf growth

Application Tip:

• Apply on wet soil to maximize nutrient uptake
• Do not apply on leaves to prevent leaf scorching

Supplementary Foliar Fertilizers for Bulb Formation:

For better bulb development, use NPK-based foliar feeds like:

• Easy Grow Vegetative
• Wuxal Macromix

These foliar fertilizers enhance nutrient absorption and support even bulb formation.

4. Bulb Enlargement Stage (Third Month After Transplanting)

Fertilizer: Calcium Ammonium Nitrate (CAN) – 100kg per Acre

At this stage, onions require more calcium and nitrogen for proper bulb enlargement.

• Calcium strengthens bulb cell walls for better shelf life
• Nitrogen supports final growth and bulb expansion

Application Tip:

• Avoid direct contact with bulbs and leaves
• Apply during early morning or late evening when soil moisture is high

---

5. Final Month: What to Avoid

Do NOT apply DAP or high-nitrogen fertilizers in the last month.

Why? Too much nitrogen delays bulb maturity, leading to small or deformed onions.

Key Final-Stage Tips:

• Keep consistent irrigation – Prevents bulb cracking or stunted growth
• Control pests & diseases – Prevents premature crop failure

Conclusion: How to Maximize Your Onion Yields

Best Fertilizer Plan for Onions in Kenya (Per Acre)

Growth Stage	Fertilizer	Amount (Per Acre)	Purpose
Before Planting	Farmyard Manure	10-15 tons	Improves soil fertility & water retention
10 Days After Transplanting	DAP	100kg	Boosts root & vegetative growth
Second Month	NPK 17:17:17	100kg	Supports bulb formation
Third Month	CAN	100kg	Enhances bulb size & quality

By following this structured fertilizer plan, you can increase your onion yields, improve quality, and maximize profits.

Want more expert farming insights? Ask your Farming questions HERE!!

About Post Author