Why Freezing Seeds at Home Is Not RecommendedUpdated 11 days ago

Freezing seeds at home is often seen as a way to extend their shelf life, but I generally advise against it. Here's why:

Seed Banks vs. Home Freezers

In professional seed banks, such as the International Seed Bank, seeds are flash-frozen at temperatures as low as -20°C to -40°C. These seeds are stored in controlled conditions that remain consistently below -20°C throughout their storage life. The environment is designed to prevent temperature fluctuations, which helps maintain the viability of the seeds.

Unfortunately, home freezers cannot replicate this. Residential freezers typically don’t reach temperatures below 0°F (-18°C), and they are opened frequently, allowing warmer air to enter. This causes temperature fluctuations that can harm your seeds.

Impact of Temperature Fluctuations

When the temperature of the seeds fluctuates in a home freezer, it forces moisture out of the seed, damaging the embryonic plant inside. This process can lead to freezer burn, which is harmful to seeds. Seeds subjected to these changing conditions often have reduced viability and may fail to germinate altogether. Since we can't maintain the stringent conditions that professional seed banks use, it's better to avoid freezing seeds at home.

Best Practices for Storing Seeds

For optimal seed storage at home, here are three key guidelines:

1. Keep Seeds Dry:
   Store seeds in a closed container with a moisture-absorbing packet to reduce humidity. Keeping the seeds dry will help prevent mold and moisture-related damage.

2. Keep Seeds Cool:
   Seeds don't need freezing temperatures but should be stored in a cool place. A room with a temperature between 65-70°F (18-21°C) is ideal for most seeds. Avoid exposing them to extreme heat or freezing conditions.

3. Keep Seeds Dark:
   Light can trigger premature germination in some seeds, so it's best to store them in a dark location, such as a cupboard or closet. While our seeds come in opaque packaging, additional darkness helps ensure their longevity.

Longevity of Seeds

Even under optimal conditions, seeds don't last forever. Seeds are living plant embryos in dormancy, and over time, they deplete their internal food reserves, weakening their viability. The older a seed is, the less likely it is to germinate. For best results, replace your oldest seeds each year. If you do decide to try germinating older seeds, keep in mind that success rates decrease as seeds age.