Most seeds will stay viable up to three years
Dear Helen: I’m about to take an inventory of seeds left over from previous years’ plantings. Seed packets almost always hold more than I can use in a growing season. For how many years can seeds be kept before they won’t germinate? I’m also not certain that my storage conditions are ideal. Should I be using the fridge or freezer? G.M.
As seed racks begin filling at garden centres and the new year’s catalogues continue arriving, it’s wise to take stock of seeds on hand to avoid duplication in your purchases.
First, make it a habit to write the year on each newly acquired seed packet. This will allow for an accurate tracking of the age of seeds.
Stored in dry, dark conditions with cool temperatures that fluctuate minimally, most flower, herb and vegetable seeds retain their viability for about three years. Exceptions: Onion, leek, corn, parsnip, verbena, strawflower, zonal geranium (Pelargonium), salvia, larkspur and lily seeds have a short life and are best kept no more than one year for sowing a second time. Among seeds that commonly keep in good viable condition for five years or more are zinnia, nasturtium, cabbage, broccoli, cauliflower, kale, lettuce, radish, cucumber, squash, pumpkin, watermelon and cantaloupe.
Moisture and warmth are the major enemies of storage life in seeds. Ideal temperatures are between 0 and 5 C. Refrigerators can be used for storing seeds, as long as they are in airtight containers with packets of silica gel. The freezer is best used only for long-term storage, and only for seeds that have been kept thoroughly dry. In a freezer, any moisture within the seeds will expand as it freezes, damaging cell walls.
If in doubt, test for germination by laying out eight to 12 seeds in a line on a piece of damp paper towel. Identify each test with a slip of paper marked in pencil with the date and variety name. Roll up the towel, seal it in a plastic bag and place it in warmth. Check regularly over 10 days, beginning after three days. If less than half the seeds have begun showing root growth, buy fresh seed. Germination percentages between 50 and 90 will indicate how thickly a variety should be seeded.
If the seed packets you buy typically hold more than you can use over several years, consider sharing seed orders with gardening friends or neighbours.
Notice to clubs: Many thanks to all the garden-related organizations that sent along information on their meetings and special events in 2017. Again this year, I invite gardening groups throughout Vancouver Island and on the Gulf Islands to send along details of 2018 activities and programs for inclusion in the events portion of columns.
If your group has finalized plans for a flower show, plant sale, meetings or other events, please send details to the email address under my picture. Note there is no “t” in Chesnut.
Send the information well ahead of its date. I submit columns to the paper at least a week to 10 days ahead of publication. Include a description of the meeting or other event with the location, time, cost of admission and points of interest. Please provide both the day of the week and the date. It’s easy enough to type in a wrong number, and a check between day and date allows me to pick up conflicts. A phone number as well as the email address is helpful.
Please place the information in the body of the email rather than in attachments. I look forward to hearing from you.