As we near the fall equinox, many of our herbs are sporting clusters of drying seeds. Perhaps this is a good opportunity for you to save a few seeds for next year’s garden. To help you along with this process here are some tips about three popular herbs and their seeds.
- To harvest basil seeds you need to let it go to flower. This reduces the leaf production (the reason you grow basil in the first place) so select only one plant for this. Harvest the seed stalks from basil as they dry, cutting them just below the flower.
- Dill seedheads grow on tall stalks that expose them to winds and birds. Allow seeds to turn brown and dry on the plant but watch them closely. Seed heads shatter easily and should be harvested quickly once the seeds are no longer green.
- Cilantro produces a central stalk that flowers and develops an umbrella-shaped seedhead. Once cilantro begins to flower the leaves lose flavor. Continue watering until the flowers fade and the seeds form. Once the seeds turn brown, clip and harvest the head.
Drying and Storing Seeds
Place your harvested seedheads in a dry place for one or two weeks to finish drying. During this time the seeds may lose as much as three fourths of their weight in water as they finish the ripening process and become completely dormant.
Do not use heat to accelerate the drying process. Seeds are living organisms that cannot survive high temperatures. Using even the lowest setting of your kitchen oven will roast them and kill the inner core.
After the drying period, it’s time to rub the seedheads between your hands to loosen the remains of the flower heads. Now you need to separate the seeds from the chaff. There are three basic ways to do this: swirling, sifting, or winnowing.
- For small seeds place the mixture in a bowl and swirl the contents with your fingers while shaking it periodically. The chaff should rise to the top where you can scoop it out with your fingers.
- Sifting can be done using colanders, kitchen sifters, or any screening. If possible, use two size meshes. One should be larger than the seeds to allow them to sift through while trapping the stems and large particles. The other should be smaller than the seeds to separate them from finer debris.
- Winnowing works best with large, heavy seeds such as beans and peas. Place the mixture in a shallow tray and gently toss it in the air, allowing the wind or a fan to drive away the chaff. Before you get too enthusiastic with this method, practice on a small amount. If the chaff and the seeds are similar in size and weight you could be blowing away as much seed as chaff.
Once harvested and cleaned, seeds should be prepared for storage. Transfer them to an airtight container and store in a cool location with steady temperatures.
Not all herb seeds are as easily harvested. Many of them are really tiny and require patience and a fine mesh to separate them from the chaff. Others may require special handling such as chilling or soaking to keep them viable. If you want to try your hand at that, consult a book on seed drying. Then again, maybe you’re best bet is to leave that to the professionals and buy new plants in the spring.