The seeds of nonfruit-bearing plants are usually harvested dry. Most flower heads as well as many vegetables, herbs, trees, shrubs, and vines produce seeds in pods that dry naturally where they stand. It is important to wait to collect seeds until the pods are nearly or fully dry. The seeds should be harvested as soon as they dry and the pods darken. Hand harvesting can be time consuming; therefore, the whole stalk can be harvested once most of the pods have dried.

     Then the seed can be separated by a process called winnowing (separating the chaff from the seeds). You've probably seen images of ancient people tossing seeds in the air from a basket to let the wind carry the chaff away, but this process is very inefficient. Today the best winnowing process is reverse screening. This is done by first using a screen with hole bigger than the seeds to sift out the large pieces of chaff. This leaves you with seeds and chaff that is approximately the same size or smaller. Then the seed is reverse screened using a screen that is slightly smaller than the seeds.

     Once your seeds are dried properly, they need to be sealed in glass jars and stored somewhere cool, dry and dark. A closet or box in a cool basement will typically work well. You can refrigerate or freeze seeds if you wish. Freezing can increase the longevity up to ten times. If your seeds would normally last three or four years with proper storage, freezing or refrigeration extends this significantly.

     If you store seeds every year, make sure that you rotate your stock to keep it fresh. Some seed storing enthusiasts periodically check the viability of the older stock of seeds by performing a simple germination test. This is done by placing perhaps ten to twenty seeds in a wet paper towel that is placed into a closed Zip-Lock bag. Place the bag in a warm place and check to see how many seeds germinate. This will tell you if your stock of seeds is reaching their limit for storage.