Preserving Cannabis Seeds for Long-Term Viability
In cannabis cultivation, genetics are gold
Whether you’re working with a cherished heirloom, a rare landrace, or a cutting-edge polyhybrid, preserving seed viability is essential.
That’s where the 100-rule comes in to play. It is a simple, science-backed guideline used by conservationists and seed banks worldwide:
Storage Temperature (°F) + Relative Humidity (%) ≤ 100
(That’s roughly Temperature (°C) × 1.8 + 32 + RH ≤ 100)
It’s a quick check on your storage environment.
40°F (4°C)? Keep RH under 60%.
50°F (10°C)? Keep RH under 50%.
Keep the total under 100 — and your seeds stay viable longer.
❄️ The Thawing Imperative
Don’t open cold containers too fast! Condensation forms instantly — and it’s the #1 cause of seed death.
Here’s why it matters:
1) Moisture triggers premature germination
2) Re-freezing forms ice crystals that rupture cells
3) Hidden mold and fungi start growing silently
To prevent this:
1) From freezer: Let sealed containers thaw at room temp for 2 hours before opening.
2) From fridge: Let sealed containers rest 1 hour before opening.
seed Storage tips for Cannabis Growers:
- Airtight containers: Use glass jars with rubber seals or vacuum-sealed mylar bags.
- Add desiccants: Silica gel or dry rice keeps humidity down.
- Store cool: Refrigeration is great for short-term. For long-term, freeze only after drying seeds to 6–8% moisture. (Tip: Dry seeds will shatter under pressure, not crush.)
- Avoid temperature swings: These cause damaging condensation.
- Label clearly: Include strain name, harvest date, and parental lineage.
Seed Longevity Cheat Sheet
| Storage Method | Typical Lifespan | Notes |
|---|---|---|
| Room temp, dark cupboard | 3–6 years | Works surprisingly well if temps stay cool and stable |
| Fridge + desiccant | 5–10 years | Best for mid-term storage with humidity control |
| Freezer + vacuum-sealed & dried | 10–15+ years | Ideal for long-term vaulting; requires careful thawing |
Whether you’re a home grower curating a personal seed vault or a breeder preserving your legacy, the 100-rule is a simple, effective tool.
Because seed storage isn’t just about preserving genetics — it’s about protecting potential.