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Why Proper Welsh Onion Storage Matters
Welsh onions (commonly called Green Onions or Scallions globally) originate from Siberia and boast exceptional cold tolerance. With annual global production exceeding 5.2 million metric tons, post-harvest losses can reach 40% without proper storage.
Below we outline the most common green onion storage methods—from professional cold storage facilities to traditional field preservation—along with important precautions.
Method 1: Cold Storage Preservation (Recommended)
Optimal Conditions:
- Temperature: -4°C to +1°C (24.8°F to 33.8°F)
- Relative Humidity: 70-80%
- Max Storage Duration: 6-8 months
Step-by-Step Protocol:
1.Preprocessing:
- Select undamaged, disease-free bulbs
- Trim leaves if storing >3 months
- Bundle into 5-7 kg batches using food-grade straps
2.Packaging:
- Use ventilated plastic crates (30% perforation)
- Avoid PVC wraps (traps ethylene gas)
3.Loading:
- Stack crates with 10cm air gaps
- Maintain floor clearance ≥15cm
4.Monitoring:
- Install CO₂ sensors (target <2000 ppm)
- Weekly quality checks for botrytis mold
Energy-Saving Tip:
Install variable-frequency compressors to reduce energy use by 32% during off-peak hours.
Traditional Storage Methods (Short-Term)
A. Trench Storage
Best For: Rural areas with dry winters
Process:
- Dig trenches 10-20cm deep × 1-2m wide
- Place bundled onions vertically
- Cover white sections with soil
- Leave tops exposed initially
- Cover with straw during <-5°C (23°F) weather
Risk: Root rot in humid climates (>85% RH)
B. Cellar Storage
Requirements:
- Constant 0°C (32°F) temperature
- 65-75% humidity levels
- Northern climates (winter temperatures <0°C)
Key Steps:
- Cure onions 7-10 days before storage
- Hang bundles from rafters to avoid ground moisture
C. Ground Storage
Procedure:
- Spread 3-4cm sand layer on wind-protected ground
- Arrange bundles root-down in pyramids (1-1.5m wide)
- Cover roots with 15cm sandy soil
- Cover with breathable fabric (no plastic direct contact)
D. Rack Storage
Ideal For: Temporary storage (<3 months)
Setup:
- Install slatted shelves (30° tilt angle)
- Maintain 5cm between bundles
- Use industrial fans for 20 air changes/hour