Storage of Seeds – It is important to remember that seeds are nature’s preferred storage vessel and, if stored properly, may frequently be used in more than one growing season. When considering how to store your seeds, you should consider the circumstances that induce and sustain their dormant state.
- Temperature, light, and humidity are among the most crucial factors to regulate.
- All three of these environmental conditions can promote the germination or decomposition of seeds.
- Seeds should be kept in containers that are airtight.
- This may be accomplished in a variety of methods, but the goal is to shield the seeds from moisture, light, and pests that may try to take up home among your nutrient-dense seeds.
Mason jars are an excellent alternative for storing loose seeds or even seed packs. Additionally, seed packets may be placed in plastic, sealable bags and then stored in Tupperware or another plastic or metal container. If humidity or moisture is an issue in your location, inserting silica gel packets can assist in controlling excess moisture. 
How long can seed packets be stored?
Each winter, I begin to consider which seeds I may plant in my garden throughout the spring and summer. Before I go too far into my planning, I rummage through the half-empty packets of seeds left over from the previous year (and in some cases, several years) and determine whether any of them are still viable.
I often shrug, sow the seeds, and wait to see what transpires. If the seeds do not germinate, I purchase replacements. By the time I discover that the seeds have not germinated, I may be weeks behind my original planting timetable. This year, though, I decided to investigate the longevity of seeds. I was quite shocked to hear that seed viability varied significantly by plant type.
The viability of seeds also varies based on whether they have been pretreated or pelletized. Even under excellent storage conditions, viability varies. This fact did not surprise me. Seeds should be kept in circumstances that are cold, dry, and dark. Place the seeds in an airtight, waterproof container, such as a jar with a rubber closure (such as a baby food jar or a canning jar) or a zip lock bag placed within a jar.
Some individuals store the seeds in a jar in the refrigerator or freezer to keep them cold (preferably below 50 degrees). Seeds that are in good condition and carefully stored will remain viable for at least one year, and depending on the plant, two to five years. On the internet, I saw several statistics displaying the average shelf life of properly maintained vegetable and flower seeds.
These sources are given in the table below. Here is a condensed form for several vegetable seeds: Onions, parsnips, parsley, salsify, and spinach for 1 year Two years: maize, peas, beans, chives, okra, and dandelion. Carrots, leeks, asparagus, turnips, rutabaga; three years Four years: bell peppers, chard, pumpkins, winter squash, watermelons, basil, artichokes, and cardoons.
The majority of brassicas, beets, tomatoes, eggplant, cucumbers, muskmelons, celery, celeriac, lettuce, endive, and chicory mature in 5 years. Johnny’s Selected Seeds (http://www.johnnyseeds.com/t-faq.aspx#questionshelflife) If you are unsure if seeds will sprout, you may do a simple germination test.
Count a specified number of seeds, between 10 and one hundred. Place the seeds on a paper towel or coffee filter that has been moistened with water. Fold or roll the damp paper over the seeds so that they do not touch, then place the paper inside a plastic bag in a warm location.
After two or three days, check the seeds daily for approximately one week. As needed, spritz the paper to retain dampness. After the typical germination period (as indicated on the seed packet) has passed, count how many seeds have germinated and compute the germination percentage by dividing the number of germinated seeds by the total number of seeds tested.
Compare the germination % to the germination rate (if any) listed on the label of the seed packet. If the seed germination rate is high, it is safe to sow the seeds. If the germination rate is poor, additional seeds may need to be purchased. Sources for table of seed viability: Vegetable seeds Virginia Cooperative Extension: http://pubs.ext.vt.edu/426/426-316/426-316.html Iowa State University Extension: http://www.ipm.iastate.edu/ipm/hortnews/1995/3-3-1995/seedv.html Vegetable and floral seeds Clear Creek Seeds: http://www.clearcreekseeds.com/seed-viability-chart/ Hill Gardens: http://hillgardens.com/seed longevity.htm
