Does refrigeration improve germination rates?
Written by
Julia Anderson
Reviewed by
Prof. Martin Thorne, Ph.D.The influence of refrigeration on seed germination is largely dependent on the type of seed and its preparation. Cold storage enables the long-term viability of many seed types. Still, it rarely enhances germination, regardless of the seed type. Knowing this difference prevents unnecessary headaches! Intuition tells us that this method will help almost everyone's seeds through the proper process for individual seeds, while maintaining the integrity of others.
Stratification Benefits
- Mimics winter conditions breaking dormancy in perennials
- Apples (Malus domestica) require 60-90 days at 33-40°F (1-4°C)
- Only applies to species evolved in temperate climates
General Seed Preservation
- Slows cellular respiration extending viability timelines
- Maintains but doesn't improve baseline germination rates
- Requires moisture below 6% to prevent ice damage
Chill only seeds that require stratification: Moisten the seeds and place them in the refrigerator for the specified period for the species. Most vegetables do not benefit from cold for germination. Refrigeration freezes their biological clock. Never chill seeds without first checking moisture levels.
Every year, verify germination rates, regardless of the storage method. Use the paper towel method each growing season. Compare to the results from other years. Seeds kept under refrigeration should remain similar from year to year. Declines indicate improper storage, and corrective action should be taken.
To extend the life of non-stratifying seeds, store them at 40-50°F (4-10°C). Use airtight containers with desiccants. Freezing seeds should only be done if the seeds are packed and are bone dry. Refrigerating seeds offers protection from heat damage, but won't change the seed's germination potential.
Read the full article: 3 Essential Rules: How to Store Seeds
