Technologies and methods for storing onions in a vegetable store
How to Preserve Onion Quality and Freshness: Proper Post-Harvest Preparation and Storage Technology
Do you want your onions to stay fresh, firm and market-ready - and stand out on supermarket shelves or wholesale markets?
Then professional post-harvest handling and proper storage are essential. The shelf life, flavor, color and overall quality of onions depend not only on the right microclimate equipment but also on correct preparation before the crop enters the storage facility.
Below is a complete guide to preparing onions for long-term storage, especially relevant for growers in India, Africa and the Middle East, where high temperatures and humidity make onion storage particularly challenging.
How to Prepare Onions for Storage
1. Cleaning and Sorting After Harvest
Immediately after harvesting, onions must be cleaned of soil, weeds and debris. This step prevents fungal growth and the spread of microorganisms that cause spoilage.
If you detect partially damaged bulbs, you can sometimes save them by removing the infected outer scales.
2. Drying (Curing)
Only fully mature and well-dried onions should be placed in a vegetable store. Proper curing helps prevent mold, rot and neck breakdown.
Curing requires active ventilation and is adjusted depending on onion variety and local climate.
Process:
-
Freshly harvested onions are ventilated with outside air.
-
The temperature of the pile rises to about +20°C due to warm external airflow entering the storage chamber.
If unripe green onions are mixed into the batch, they cannot be stored under standard conditions. For these, drying temperature should be increased to +30°C to avoid neck rot, which develops quickly at +22…+25°C.
Typical curing duration:
-
6 weeks
-
8–9 hours of ventilation per day
-
Air exchange capacity: 200–250 m³/t per hour
Once curing is completed, maintenance ventilation of 4 hours per day is generally sufficient.
3. Gradual Cooling Phase
After drying, begin lowering the temperature step by step — 0.5°C per day until it reaches +20°C in the storage chamber.
To prevent moisture condensation, ventilate with outside air for 10–15 minutes every 3 hours during the cooling stage.
Storage Options for Onions
Once onions are cleaned, sorted and fully cured, they are ready for storage.
Microclimate systems must maintain both temperature stability and optimal humidity, because onions are extremely sensitive to excess moisture and sudden climate fluctuations.
High humidity leads to mold and rot, which spread quickly from one bulb to another. To avoid this, ventilation should operate 15 minutes every two hours.
Microclimate Technologies We Typically Use in Onion Storage Projects
Agrovent implements several advanced systems designed specifically for long-term onion storage:
-
Combined Ventilation System
-
Aspiration Wall Technology
-
Dragon-M High-Pressure System
Each project is engineered individually, taking into account:
-
onion variety
-
volume of harvest
-
climate zone
-
storage building design
-
operational goals
-
energy efficiency requirements
We fine-tune all parameters at the design stage to ensure maximum shelf life and minimal losses.
Key Storage Parameters You Should Always Follow
Regardless of the storage system, some rules are universal:
-
No temperature differences inside the pile
-
Cooling must start only after drying is fully completed
-
Optimal relative humidity: 75%
-
Storage temperature: 0 to +1.5°C
Following these guidelines helps maintain firmness, prevent sprouting, and significantly extend shelf life — especially important for regions with hot climates.
Need Help Designing a Storage Facility for Onions?
Whether you require expert consultation or a complete turnkey technological solution, our specialists are ready to assist.
📞 Call: +971 50 437 7119
📧 Email: info@agrovent.com
More articles
Potato storage technology
Learn how bulk and container potato storage systems work, how to manage drying, healing, cooling, humidity and CO₂, and how to protect quality long-term
News
Napa cabbage. Storage parameters
earn optimal conditions for long-term napa cabbage storage: temperature, humidity, and controlled atmosphere. Ideal solutions for India, Africa, and Saudi Arabia
News
How to prepare the vegetable storehouse for the potato storage season?
Learn how to prepare storage facilities, manage curing, prevent diseases, and handle potatoes correctly to ensure long-term quality and minimal losses
Expert Talk: Microbial Preparations for Onion Storage in Maharashtra
Aspergillus niger (black mold) is the biggest threat to onions stored in warm, humid regions like Maharashtra. Learn which biocontrol microorganisms work best, how to apply them, and what results to expect when combined with proper storage conditions.
News
Key Factors for Investing in Agriculture
Learn why agriculture is a stable long-term investment. Key benefits, risks, and strategies for choosing profitable agri projects in India, Africa, and the Middle East
News
Garlic. Storage parameters
Preparation of the product. The volume of goods. Storage temperature.