Plant nutrition in onion: recommendations by phenological stage

Growth Stages

Onion (Allium cepa) is a medium-long cycle bulbous vegetable that requires balanced nutrition to achieve good size, firmness, and post-harvest life.

The use of nutritional programs tailored to each phenological stage helps improve bulb yield and quality. Below are the crop’s development stages and their key nutritional requirements.

Germination and emergence

Occurs between 7 to 14 days after sowing. It is critical for crop establishment and depends on adequate soil moisture and temperature.

Vegetative development

The plant produces long, narrow leaves, increasing its photosynthetic capacity. This is a key stage for the absorption of Nitrogen, Phosphorus, and micronutrients such as Zinc.

Bulb formation and thickening

This occurs when there is sufficient leaf accumulation. It is highly dependent on the photoperiod. The demand for Potassium, Calcium, and Boron increases.

Maturity and drying

The foliage begins to decay and the bulb’s outer skin hardens. Reduced irrigation and nutritional balance contribute to improved post-harvest preservation.

Harvest

This is done when at least 70% of the foliage is dry or bent. This is a key moment for ensuring quality and minimizing damage.