Dr. Leonard Perry, UVM Extension Professor
Saving seeds from annual flowering plants is a good way to save money, as well as grow your favorites again the following year. It also allows you to grow non-hybrid heirloom plants, which may be hard to obtain through seed catalogs or nurseries. Many gardeners also save seeds in order to swap them with others for varieties, often unusual or difficult to find, to try in the garden.
Before you start collecting seeds, there are a few things you need to keep in mind. The first is that plants grown from hybrid seed will not produce exact replicas of the plant from which you are taking the seed. So, it may not be worth the effort to save these seeds.
Another scenario where you won't want to save seeds is if you grew more than one variety of the same plant. If you did, chances are good that the plants cross-pollinated, which again, produces plants that will in no way resemble the parents. If you want to see what you will get, however, this may be a fun experiment!
If you want to collect seeds from perennial flowers, do so only from species of wildflowers. Most of the perennials you grow in your garden are cultivars, or cultivated varieties. This means you will only get true "duplicates" from vegetative means, such as cuttings and divisions.
Collect seeds only from the healthiest plants. Wait until the flower has stopped blooming and the seed heads or pods are fully developed and have begun to dry. You'll know when the time is right as the flowers will have faded, the flower heads will look dry and start to fall apart, and the seed heads or pods will turn tan or brown and become dry and brittle. Picking off the pods too early will not produce viable seed.
Use a pair of scissors to carefully remove the dried flower heads or pods. A surefire way not to lose any seed while collecting is to several cut flower stalks, tie them together, and hang upside down in a brown paper bag in a dry location for several days. As the seed heads dry, the seeds will drop to the bottom of the bag.
The next step is to separate the debris or chaff from the actual seeds. Why is this important? Because the chaff may contain moisture, which will cause mildew or mold that may infect and kill the seed.
Before storing, make sure the seeds are completely dry. Spread the seeds on a piece of waxed paper or other non-stick material. Don't use paper towels or paper plates as the seeds may stick. Drying could take anywhere from a few days to a few weeks.
Once dry, sort your seeds according to variety and place in individual envelopes or small paper bags. You might want to jot a quick description on each, including variety name, color, height, and other characteristics that will help you when you plan next years' flower garden. Or place seeds in clean, airtight glass containers such as baby food jars. Adding an antidessicant material, such as corn meal, to the bottom of the jars will help reduce the moisture in the jars.
Store in your refrigerator, if space, or a cool, dark, dry location such as a basement. If stored improperly, warmth and moisture may cause the seeds to sprout prematurely or encourage the growth of mold.
For best results, keep the container closed until you are ready to plant or swap the seeds. Stored seeds will retain remain viable for different amounts of time, up to several years, depending on variety.
Before planting, test your seeds for germination by placing a few between two sheets of wet paper towels. Roll up the towel and place inside a plastic bag so it won't dry out. Keep in a warm place. Check after a few days to see if the seeds have sprouted.
Following these tips for saving, sorting, and storing seeds should ensure successful sowing in the future.