Seeds purchased for the current gardening year usually yield top germination rates. But what about the leftovers from previous seasons? It doesn’t take but a year or two of gardening to accumulate a backlog of partially used packets of seeds. Depending on what those seeds are and how you store them, many may be good for several seasons to come.
My Seed Storage Box
Over the years I’ve tried many seed storage schemes, including the freezer, which can prolong seed viability in many species, but proved impractical in my busy kitchen. The seed storage set-up that works best for me consists of a plastic storage bin with a snap-top lid. Inside the bin, seeds are sorted by plant family or type, with each category tucked inside a plastic bag. For example, the cucumber family has its own bag, tomato family crops are kept together, root veggies are together, and flowers and herbs have their own bags, too. Some bulky beans and other large seeds are stored in small glass jars.
In addition to the seeds, my box includes various desiccant packets saved from shoes and other purchases (see more about keeping humidity low below). Finally, there is room in the box for my rudimentary sifters, made by stretching nylon netting over embroidery hoops (purchased for pocket change at the thrift store). These come in handy when I want to clean seeds I saved the previous season, which often go into the box as a mess of seeds and chaff stuffed into an envelope.
Chaos creeps into the box when the growing season gets busy. During my winter renovation, I might also find every packet I planted (and replanted) during the month of August held together with a rubber band. Until I learned to securely tape seed packets shut, I would also encounter a shifting sea of mixed seeds at the bottom of the box. These I fed to the birds.
Low Humidity Seed Storage
But back to low humidity, which is my biggest seed storage challenge, especially in summer when I am constantly opening the box during humid weather. You really don’t want your seeds subjected to high humidity levels over and over again, particularly when temperatures are warm. Repurposed desiccant packets from shoes and electronics packaging contain silica gel, which absorbs moisture from the air. I’ve also made small rice packets to further keep humidity low inside my seed storage box.
Keep Up With Dates
In midwinter, I spend a couple of hours sorting through my collection to put seeds in their proper groups, and to cull out old seeds that may not germinate well. As shown in the chart below, vegetable seeds vary in how long they last, assuming they have been given storage conditions that are conducive to preserving seed viability.
Note that this data is not carved in stone. Some sources suggest that lettuce seeds last up to 6 years, but my experience has been that lettuce seeds more than one year old will either make a magnificent stand or be total duds. For this reason, I buy new packets of lettuce seed each spring, and try to use them up in the fall. Onion seeds don’t read germination charts, either, but I often see a steady decline in the germination rate of onion family seeds after the first year. If I buy a packet that has more onion seeds than I need, I pass them on to a gardening friend rather than letting them age beyond their prime.
|When to Discard
||Commonly Grown Crops
|After 5 years
||Cucumber, melon, radish, collards, annual flowers
|After 4 years
||Aubergine, tomato, squash
|After 3 years
||Beans, peas, cabbage family crops, carrot family crops
|After 2 years
||Leek, mesclun, sweet corn
|After 1 years
In order to keep up with the age of my seeds, I make sure their vintage years are written on each packet. Most seed packets already have this information on them, so I circle it so I’ll be careful not to tear it off and throw it away. I store most of my home-saved seeds in paper envelopes, which are easy to write on with a pencil or pen. This year, pretty much everything before 2007 will go if it’s not gone already.
I tend to have expensive taste in seeds, so I try not to waste them. It often takes me three seasons to use up a packet of broccoli or tomato seeds, so using good seed storage practices save me time and money. If you’ve found a different approach that works well for you, please share it below.
By Barbara Pleasant