Storing Seed for Maximum Vitality
Each seed contains a tiny embryo—amazing! Protecting that embryo through careful seed storage is key to maintaining the vitality and vigour of your future plants. Properly stored seeds can remain viable for years—even centuries—though most will thrive for a few seasons when kept in optimum conditions.
At Transition Farm, we strive for seed that wants to grow—seed that germinates quickly, thrives in ideal conditions, and shows true heartiness. This is the balance of seed viability and seed vigour.
What Reduces Seed Life
Two main factors work together to shorten a seed’s lifespan:
- Relative Humidity
- Temperature
How to Maintain Seed Viability and Vigour
DRY AND DARK
Excess humidity and UV light quickly deteriorate seed quality.
COOL AND CONSTANT
A consistently low temperature is far better than one that fluctuates.
SEED STORAGE — Simple Do’s and Don’ts
Each seed holds a spark of life. Protecting that vitality through proper storage ensures strong germination and healthy plants for seasons to come.
DO
Ensure your seed is fully dry before storage.
- New, sealed packets from reputable companies are ready to store.
- If you’ve opened packets and they’ve been exposed to air, place them in a glass jar or ziplock bag with desiccant for 3–5 days to remove residual moisture.
- If you’ve harvested your own seed (YAY!), make sure it’s completely dry before storing.
How to test dryness:
- Pumpkin and larger seeds: Use the bend test — a dry seed will snap when bent.
- Onion seed: Try grinding a few in a mortar and pestle; if they powder easily, they’re dry.
- Lettuce, tomato, and capsicum seeds: Use tweezers to attempt a gentle snap.
Store seeds in airtight containers in a cool, constant environment.
- Use glass jars or sealed tins with desiccant packs.
- Ideal temperature: around 5°C.
- A stable, cool space is far better than one that fluctuates. Even household fridges can vary.
- Possible storage spots: a bar fridge, dark cupboard, basement (watch humidity), or a southern room with no windows.
- Use a max/min thermometer to find the most stable location.
Protect your seed from insects and rodents.
- Use sealed jars, tins, or metal containers.
- Rodents can chew through cardboard and even some plastics!
Let cold-stored seed warm up before opening.
- Remove from cool storage at least 12 hours before opening to prevent condensation from reducing seed viability.
Remember:
- Sealed packets last longer than opened ones.
- Buy fresh seed each season — but if you have extras, store them properly.
Storing excess seed:
- After opening, quickly remove what you’ll use.
- Add a desiccant to the packet and seal it.
- Leave in a cool, dry place for a few days.
- Remove the desiccant and re-store the packet in an airtight container in a fridge or cool cupboard.
DON’T
-
Don’t store seed in your propagation area.
- These spaces are often humid and warm with fluctuating temperatures.
-
Don’t put dirt into seed packets.
- If you only need part of a packet, remove that portion instead of contaminating the rest.
-
Don’t buy more seed than you can store properly.
- Unless you’re prepared to maintain optimum conditions.
- If you’re worried about a variety selling out, buy extra — but store it carefully to preserve its viability.
Remember “The Rule of 100”
Your storage temperature (°F) plus relative humidity (%) should total no more than 100.
For example:
At Transition Farm, we store our seed at about 35% humidity and 5°C (40°F) — our magic number is 75!
Seed Shelf Life by Variety
We include a general “use by” date on each packet, but seed vitality depends on many factors:
- The health of the mother plant
- Seasonal growing conditions
- Harvest stage and handling
- Drying process
- Storage environment
While some seed families are naturally longer-lived than others, the best indicator of vitality is regular germination testing — which we perform and label on every packet.
Want to learn more? Read our guide on How to Germination Test Seed and share how you manage your own seed stash in the comments!