How to Store Seeds
Mark Macdonald | July 29, 2020
One of the factors that most influences the germination rate of seeds is how they are stored. Like the plants that produce them, seeds come in all sorts of forms and sizes. They are also variable in their longevity. Since seed packets often contain more seeds than might be needed in one season, it’s important for gardeners to learn how to store seeds.
Vegetable seeds that are considered “long-lived” include the Brassicas (broccoli, Brussels sprouts, cauliflower, cabbage, collards, kohlrabi…) the chicory group (endive, escarole, radicchio), cucumber, kale, lettuce, melons, mustards, peppers, radish, rutabaga, sunflower, tomato and turnips. Stored correctly, these seeds should maintain a good viability for more than five years.
“Medium-lived” varieties include beans, carrots, celery, chard, eggplant, parsley, peas, pumpkin, salsify, and squash. These varieties, if properly stored, should last up to five years.
“Short-lived” seeds include corn, leek, onion, parsnip, and spinach. These are generally not recommended for more than one season, although they may maintain acceptable germination rates in the second year.
Pelleted seeds should be bought fresh each year.
Some tricks to keeping seeds and getting the best germination:
The secret to successful seed storage is “cool and dry.”As soon as your seeds arrive, store them immediately in an airtight container in a cool spot, away from any obvious heat source, and out of the sunlight. Try and store them at 4 – 10°C (40 – 50°F). The refrigerator is not ideal, as it tends to fluctuate in humidity. Freezing will kill many seed varieties. It’s true that government-run seed vaults freeze their seeds, but they do so in laboratory conditions with specialized equipment and controls that few of us could ever simulate at home. Some people like to include desiccant packets with their seeds to ensure a dry environment. One other trick is to wrap a teaspoon of milk powder in a piece of tissue, and use this the same way. This will absorb any available moisture in the airtight container.
Only ever use sterilized starting mix when starting seeds indoors. Regular soil is teeming with microbes, including certain fungi that can cause damping off of seedlings, and bacteria that can harm the seeds themselves.
Once the seeds are planted, keep the temperature constant. Aim for continuous temperatures of 20 – 24°C (70 – 74°F) both day and night.
Once the seeds are planted, never let them dry out. Seeds absorb oxygen as they germinate, so too much water can deprive them of this vital gas. Aim to keep the soil evenly moist. Seed starting soil is designed to provide both water retention and drainage.
Ventilate seedlings. One mistake that is easy to make is to leave the plastic dome over seedling trays on a hot, sunny day. If there is significant condensation on the plastic dome, remove it or prop it open to allow air to get in and out. On a sunny day, seedling tray domes can actually steam your seedlings.
Finally, harden seedlings off before transplanting them outdoors. Sudden plunges into cold, damp conditions can cause enough stress on young plants to cause severe stunting or death. Make the transition gradual. Using a cold frame or cloche works well.
6 Tips for Storing Seeds Saved From Your Own Garden
A little powdered milk can help you grow your favorite plants again and again.
You’ve harvested your summer seeds and now it’s time to store them to help you get a jump-start on next season — but storing them improperly could make your dreams of a bountiful garden fall flat. Follow our easy guide to storing your saved seeds that will save you time and money and give you your best harvest yet.
1. Dry the seeds.
If you’re gathering and saving seeds from your own plants, spread the seeds on newspaper and let them air-dry for about a week. Write seed names on the newspaper so there’s no mix-up. Pack the air-dried seeds in small paper packets or envelopes and label with the plant name and other pertinent information. Remember, if you want to save your own seeds, you’ll need to plant open-pollinated varieties. They’ll come back true; hybrids won’t.
You can also dry saved seeds on paper towels. They’ll stick to the towels when dry, so roll them up right in the towel to store them. When you’re ready to plant, just tear off bits of the towel, one seed at a time, and plant seed and towel right in the soil.
2. Stash them somewhere airtight.
Put the packets inside plastic food storage bags, Mason jars with tight-fitting lids, or glass canisters with gasketed lids.
To keep seeds dry, wrap two heaping tablespoons of powdered milk in four layers of facial tissue, then put the milk packet inside the storage container with the seed packets. You can also add a packet of silica gel in with the seeds. Replace every six months.
3. Put the containers in a dry and cool place.
Humidity and warmth shorten a seed’s shelf life, so the refrigerator is generally the best place to store seeds, but keep them far away from the freezer.
4. Toss any seeds pass their prime.
Store each year’s seeds together and date them. Because most seeds remain viable about three years, you’ll know at a glance which container still has planting potential.
5. Prepare for planting.
When you’re ready to plant, remove the containers from the refrigerator and keep them closed until the seeds warm to room temperature. Otherwise, moisture in the air will condense on the seeds, causing them to clump together.
6. Expect a few duds.
Even if you’re organized, methodical, and careful about storing seeds, accept the fact that some seeds just won’t germinate the following year. Home gardeners will find that stored sweet corn and parsnip seeds in particular have low germination rates, and other seeds will only remain viable for a year or two.Saving seeds for next year? You’ll need to store them properly to ensure good germination. ]]>