Onion seed

When sourcing onion seeds, the most critical metric is the Germination Rate, which should ideally be above 85%. Buyers must request a Seed Analysis Certificate that specifies the Purity Level (minimum 98%) and Moisture Content (typically below 7-8%) to ensure long-term storage stability. Additionally, verify the Seed Vigor to ensure uniform emergence under field conditions.

Selection must be based on Photoperiod Sensitivity: Short-day varieties (require 10-12 hours of light), Intermediate-day, or Long-day varieties (14-16 hours). Choosing the wrong type will result in failure to bulb. Furthermore, prioritize seeds with Disease Resistance traits, specifically against Pink Root, Fusarium Oxysporum, and Downy Mildew, to reduce pesticide reliance and crop loss.

Suppliers must provide an ISTA (International Seed Testing Association) Orange Certificate for quality assurance. For cross-border entry, a Phytosanitary Certificate issued by the exporting country's national plant protection organization is mandatory to prove the seeds are pest-free and non-GMO (unless specified otherwise). Ensure the packaging complies with ISPM 15 standards if wooden pallets are used.

Many professional buyers prefer Film-Coated or Pelleted seeds. Coating with Fungicides (e.g., Thiram) or Insecticides protects the seedling during the vulnerable early stages. Pelleting increases the seed size and uniformity, making them compatible with Precision Vacuum Planters, which significantly reduces labor costs and optimizes plant spacing.

The biggest risk is Customs Seizure due to non-compliant documentation or prohibited species. Always verify the Import Permit requirements of your specific country before shipping. To secure the transaction, use Trade Assurance services on Made-in-China.com and consider Third-Party Pre-shipment Inspection to verify that the seed lot number matches the test report.

Negotiate based on Seed Count (per million seeds) rather than just weight, as seed size varies. For logistics, onion seeds are highly sensitive to temperature and humidity; insist on Climate-Controlled Shipping (Reefer containers) or vacuum-sealed moisture-proof foil packaging. Request Tiered Pricing where a 20% discount is typically achievable for volumes exceeding 500kg.

Prioritize Audited Suppliers on Made-in-China.com who have a proven track record in agricultural exports. Request Trial Samples (100g-500g) for greenhouse testing before committing to a bulk purchase. Check if the supplier has R&D capabilities or maintains their own Breeding Bases, which indicates better control over genetic purity compared to simple traders.