As a rule, smaller seeds do not last as long as larger seeds, as there is more stored energy in the big ones. This "rule" is especially true if the seeds were not stored in the best conditions. The best place would be in a tight-sealing container in the refrigerator. These seeds are alive the entire time we have been storing them. Lower the storage temperature and the respiration rate lowers too, conserving that energy. Compare the size of lettuce seed to a snap bean and you get the idea.
A simple germination test provides important information for when we go to plant them outdoors directly or to start those seeds to become transplants for later. Only a small portion of each of seed types saved is tested.
Take 10 seeds, place them between moist paper towels on a small dish of your choice, and place that inside a plastic bag that closes. As the seed begins to absorb moisture from the towel, the seed swells and germination begins. After a few days pass, count those seeds that have produced a seedling. This provides you with a percentage of germination (i.e. if eight out of 10 seeds germinate this means an 80 percent germination rate). This helps with planning, especially if you will need a specific number of transplants or so many plants per row in the garden. For example, at an 80 percent rate, you will need to seed about 20 percent more to give the desired outcome.
Another one of those seed storage "rules" is that for every year you save seeds, germination rates drop about 10 percent. This is another way to figure out how much more seed you will need to sow outdoors or how many more seedlings you will need to move into transplant containers.
The seed packs you buy can tell us just how fragile seeds can be. Seed packs made out of foil or that are foil-lined suggest that once opened, the storage time and seed germination rates will fall quickly enough that saving them for even just one year may be too long. Paper seed packets suggest a much longer lasting seed.
Seed packets also give us great additional information. Some seeds will need to be in the dark to germinate, while others require light. Some seeds will need cooler soil temperatures while others need a warmer soil to begin life. This holds true for planting directly outdoors and once seeds become seedlings indoors.
Try this little botany experiment with the family while we wait for spring. Together, you can observe and make some notes like date started and when you first saw the seeds swelling, the date you saw the root radical emerge and when those funny looking cotyledon leaves appear. Your family can learn more about plants and seeds at https://extension.illinois.edu/gpe.
The Kendall County Master Gardener Help Desk resumes for 2018 in March – Monday, Wednesday and Friday from 9 a.m. to 12:30 p.m. at 630-553-5823. Richard Hentschel is a Horticulture Extension Educator with University of Illinois Extension, serving DuPage, Kane and Kendall counties. Stay tuned to more garden and yard updates with This Week in the Garden videos at facebook.com/extensiondkk/videos and the Green Side Up podcast at go.illinois.edu/greensideup.