How to Cure, Harvest, and Preserve Bulb Onions

Our last articles on professional onion farming in Kenya discussed the suitable varieties to produce, raising them, irrigating, applying fertilizers, and controlling diseases. This last article on onion farming will examine the suitable curing methods, harvesting, and preservation of bulb Onion farming in Kenya.

Harvesting

Depending on the variety and management, onion harvesting can be done 90 – 150 days after transplanting.

When are onions ready for harvest?

Bulb Onions are ready for harvesting when the leaves collapse, or 75 % of the crop tops have dried and fallen over. Leaf tops begin to discolour, bend and dry towards the ground, and sheath leaves surrounding the bulbs reduce thickness.

What is “Curing”?

Curing is a process intended to dry off bulbs’ necks and outer leaves.

The main objective is to prolong shelf life by preventing moisture loss and attack by diseases.

Curing can be done in the field or a protected environment away from adverse weather conditions, such as rain or direct sunlight.

Field Curing

Curing can occur in the field if the maturity and harvesting coincide with dry months.

Place harvested onions in rows with leaves partially covering the bulbs to prevent sunburn or greening.

Onions are left in the field until the outer leaves and neck are completely dry and papery.

Field curing can take 2 – 3 weeks depending on the environmental condition Protected Curing.

Drying Onions in a protected environment

Do Curing in a warm, dry, and well-ventilated location protected from direct sunlight and rain.

The process involves the following:

• Removal of excess soil
• Trimming of foliage, leaving 2.5cm of the section of stem at the neck
• Placing onions in a single layer in a large flat tray

Curing can be done by tying the tops of bulbs in bunches and hanging them on a horizontal pole in a well-ventilated shade.

Read Also

• Onion farming|This is how to Irrigate and apply fertilizers
• How to control the most destructive pests in onion farming
• Onion seedlings-How to raise and transplant them successfully

Value Addition Techniques

Sorting– this is the process of removing foreign material from onions.

Before storage, sort the bulb Onions and remove the following:

• Onions with thick necks
• Onions that have bolted
• Injured onions
• Decayed onions
• Doubles and small bulbs

Grading

Always do grading before & after storage.

For the domestic market, put onions into 3 Grades: large, medium, and small.

Bulbs must be:

• Intact with firm flesh that is not exposed
• Clean and free from visible foreign matter
• Sufficiently dry with the first two outer skin and stem fully dry
• Free from abnormal external moisture
• Free from foul smell

Many thanks to the Ministry of Agriculture, Livestock, and Fisheries (MOALF), Agriculture and
Food Authority (Horticultural Crops Directorate (HCD)) of the Republic of Kenya and the Japan International Cooperation Agency (JICA).

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