Harvesting, Post-Harvest Handling & Storage

Johnny's Founder, Rob Johnston, Jr. • by Craig Dilger for the New York Times

Seed Storage Guidelines • Simple charts & notes on longevity for the beginning seed-saver

Our founder, Rob Johnston, Jr. (now retired), at Johnny's climate-controlled seed warehouse facility in Winslow, Maine
Photo credit: Craig Dilger for The New York Times

Interested in saving seeds? You need not build a climate-controlled warehouse or start a seed company to try your hand — it's a global, ancestral practice. But there are some caveats for success, relating to the crop, seed condition, timing, and storage conditions…

How long can seeds last in storage?

The seeds of many — though not all — commonly grown crops will remain viable in storage for one to several years if stored under optimal conditions — namely, cool and dry, with low temperature (42°F or 5.6°C) and low percent humidity. A simple rule of thumb is that the sum of the temperature (°F) and percent relative humidity should be less than 100.

The actual storage life, however, will depend upon the viability and moisture content of the seed when initially placed in storage, the specific variety, the conditions of the storage environment over time, and other variables.

As a simple way to store seeds for gardeners and farmers, we suggest keeping seeds in a sealed glass jar in the refrigerator. Be sure to label the jar with crop, storage entry date, and any other info you may find useful or of interest later on. For best results, include a desiccant in the jar.

If your seeds have been stored for any length of time, you may wish to test a sample of the seeds to see if they still germinate well. Place some seeds between two damp pieces of paper towel, enclose them in a zip-lock sandwich bag, and place the bag in a temperature-controlled environment suited to the variety's specific germination requirements. (Refer to the packet back or the product page on our website for optimal germination temperature range.) After several days — or longer for slow-to-germinate varieties — check to see how many of the seeds have germinated.

Keep in mind, however, that both germination rate and seed viability can decline with age of the seed. Viability refers to a seed's ability to produce a vigorous seedling. Seed viability typically declines before germination rates do, so it is possible for old seed to still germinate yet produce weak seedlings.

When retrieving seeds from storage, allow the container to reach room temperature before opening it. This will help prevent condensation from forming on the seed surface and inside the container.

What is the average storage life of garden crop seeds under favorable conditions?

NOTE: The charts below reflect an average range derived from our experience and data gathered from expert sources (see References & Further Reading).

Your results may vary from ours, depending upon environmental variables and the condition of the seed prior to storage.

Please also note that all data shown here are for raw seed.

Pelleted seed, regardless of variety, should be used within one year, as the pelleting process diminishes seed longevity.

Farm Seed & Cover Crop Seed Storage Chart

Type Avg Storage Life (Yrs) Type Avg Storage Life (Yrs)
Alfalfa 2–5 Rapeseed 3–5
Barley 3–5 Rye 1–3
Buckwheat 2–5 Sorghum 1–2
Cowpea 5 Sudangrass 1–4
Clover, Crimson 5 Vetch, common 3–5
Clover, White 5 Vetch, hairy 5
Millet 1–2 Wheat, common 3–5
Oats 1–4    

Vegetable Crop Seed Storage Chart

Type Avg Storage Life (Yrs) Type Avg Storage Life (Yrs)
Artichoke & Cardoon 1–4 Kohlrabi 3–5
Arugula 6 Leeks 2–3
Asian Greens 3 Lentil 1–2
Asparagus 3–4 Lettuce 1–6
Beans 2–4 Melon 3–6
Beets 2–5 Mustard 4
Broccoli 3–5 Okra 2–3
Brussels Sprouts 3–5 Onions 1–2
Cabbage 3–5 Parsnip 1–3
Cabbage, Chinese 3–5 Peas 2–4
Carrots 3–4 Peppers 2–5
Cauliflower 4–5 Pumpkins 4–6
Celery & Celeriac 3–5 Purslane 3–5
Chicory 4–5 Radish 4–5
Collards 3–5 Rutabaga 3–5
Corn, Sweet 1–3 Salsify 1–2
Cress 5 Soybean 3–5
Cucumber 3–6 Spinach 1–5
Dandelion 1–2 Squash & Gourds 3–6
Eggplant 4–5 Swiss Chard 2–5
Endive 5 Tomato 3–7
Fennel 3–4 Turnip 4–5
Kale 3–5 Watermelon 4–5

Herb Crop Seed Storage Chart

Type Avg Storage Life (Yrs) Type Avg Storage Life (Yrs)
Angelica 2 Lavender 4
Anise 1–3 Lemon Balm 1–4
Basil, sweet 3–5 Lemon Grass 3
Borage 1–4 Lovage 1–3
Caraway 1–2 Marjoram 1–4
Catnip 3 Mexican Mint Marigold 4
Chamomile 4 Mountain Mint 4
Chervil 1–4 Oregano 4
Chives 1–3 Parsley 1–4
Cilantro/Coriander 1–4 Rosemary 1–4
Cumin 1–3 Sage 1–3
Dill 1–4 Savory 1–4
Epazote 3 Thyme 1–4
Fennel 1–2 Valerian 2–3
Hyssop 1–4    

Fruit Crop Seed Storage Chart

Type Avg Storage Life (Yrs) Type Avg Storage Life (Yrs)
Melon 3–6 Strawberry 5
Rhubarb 1–2 Watermelon 4–5

Flower Crop Seed Storage Chart

Type Avg Storage Life (Yrs) Type Avg Storage Life (Yrs)
Ageratum 3–5 Gomphrena (Globe Amaranth) 3–5
Agrostemma 3 Gypsophila 2–4
Alyssum 3–5 Hyacinth Bean 3–5
Ammi 2 Impatiens 1–2
Amaranthus 4–5 Larkspur 1–3
Aquilegia (Columbine) 1–2 Lavender 1–3
Artemisia 1–5 Lisianthus 2–3
Asclepias 1 Lupine 3–5
Aster 1–2 Marigold 2–5
Bachelor’s Buttons 3–5 Matricaria 1–3
Bells of Ireland 2 Monarda 4
Calendula 4–6 Nasturtium 3–7
Carnation 3–5 Nigella 3–5
Celosia 2–4 Pansy 1–2
Centaurea 1–5 Phlox 1–3
Coneflower 1–2 Poppy 2–4
Cosmos 3–5 Salvia 1–3
Dahlia 2–5 Saponaria 2–5
Daisy 3 Scabiosa 2–5
Delphinium 1–3 Snapdragon 3–5
Dianthus (Sweet William) 3–5 Statice 1–2
Didiscus 1 Stock 4–5
Digitalis 1–2 Strawflower 1–2
Dusty Miller 3–5 Sunflowers 3–5
Echinacea 4 Sweet Pea 3–5
Eryngium 2 Verbena 1–5
Eucalyptus 4 Viola (Pansy) 1–2
Euphorbia 4 Yarrow 3–5
Forget-me-Not 2 Zinnia 2–5

Learn More

Growing Garden Seeds, by Rob Johnston, Jr
First published in 1976, Growing Garden Seeds covers 15 fundamentals for successful seed production, harvest, and storage.

Johnny's Seed-Saving Resources

References & Further Reading