How long do seeds remain viable in mason jars?
Written by
Julia Anderson
Reviewed by
Prof. Martin Thorne, Ph.D.Mason jars offer excellent seed storage protection when used correctly. They are made of glass so that they will keep moisture out, allowing us to see our seeds. Properly stored, seeds will last 3-8 years in jars. Success is really dependent on appropriate preparation and maintenance. This will also briefly explain the key factors that affect viability.
Initial Preparation
- Seeds must pass the snap test showing <8% moisture
- Use oxygen absorbers for seeds stored beyond 3 years
- Fill jars ¾ full to allow air circulation space
Environmental Control
- Maintain temperatures below 50°F (10°C) consistently
- Keep jars in complete darkness using cloth covers
- Store away from heat sources like appliances
Inspect jar seals every three to four months. Examine rubber gaskets for flexibility, and discard any gaskets that are hard or cracked. Watch for changes in the color of the silica gel packets. If the packets transition from blue to pink, they have absorbed moisture and need to be replaced. Rotate the positions of the jars to avoid temperature gradients.
It is good practice to test germination for long-term-stored seeds every year. Use the paper towel method every spring and keep a journal to document germination rates. If rates fall below 70% when planting, decrease the planting density. Seeds stored in mason jars can be preserved for seed heritage with care.
Read the full article: 3 Essential Rules: How to Store Seeds
