How to Store Leftover Seeds Over Winter
Keep seed dry, cool, and dark: a sealed glass jar with a desiccant, at about 40F to 50F. The refrigerator works; the freezer only for very dry seed. Label...
Published by ThriveThyme
seed storage seed stash seed viability winter fall
How to Store Leftover Seeds Over Winter
Heat and moisture are what age seed. Keep packets dry, cool, and dark, and most vegetable seed lasts 3 years or more. Fall cleanup is the time to gather loose packets before they spend a winter in a damp shed.
The Short Version
- Seal packets in a glass jar with a tight lid.
- Add a desiccant: a silica gel pack, or a spoon of dry milk powder folded in a tissue.
- Store the jar somewhere cool and dark. About 40F to 50F is ideal. A refrigerator works.
- Label every packet with the crop, variety, and packed-for year.
Step by Step
- Collect every packet. Check the shed, garage, and garden bag. Toss anything that got wet and clumped.
- Dry saved seed fully. Homegrown seed should dry on a screen or paper plate out of direct sun until it snaps or feels hard. Damp seed molds in a jar. For tomatoes, see How to save tomato seeds.
- Label. Write the year on any packet that lacks it. Put homegrown seed in a paper envelope with the crop, variety, and year.
- Jar it. Put the packets and a desiccant in a glass jar. A tight lid also keeps out mice and insects.
- Pick a cool spot. A cool closet, a basement, or the refrigerator. K-State Research and Extension notes a refrigerator is a better choice than a freezer, which can harm seed that is not very dry.
- Let a cold jar warm before you open it. Opening a cold jar in a warm room lets moisture condense on the seed.
Where Not to Store Seed
- A hot garage, attic, or shed
- A sunny windowsill or a car
- A damp basement floor without a sealed container
- Loose in a garden bag next to fertilizer
Before You Order for Spring
Sort packets by age with the seed life chart. Short-lived seed (onion, leek, parsley, parsnip) is usually worth buying fresh each year. Test the borderline packets with a paper towel germination test.
Saving seed from your own plants this fall? The Seed Saving Desk shows which crops come true and how to dry them.
The Seed Viability Check does the sorting for every packet in My seed stash and has a storage checklist that saves in your browser.
Sources: Iowa State University Extension, K-State Research and Extension, Illinois Extension.