Mike Kwiatek, University of Illinois Horticulture Student and Plant Clinic Student Worker
If you haven’t started collecting seeds yet, it may not be too late. Seed collecting is a fun pastime that provides you with plants for the following years to come, lets you share favorite varieties with friends, and saves you some money for the next season. Many home gardeners collect seed and some even participate in seed exchanges, which allow gardeners to meet and share some of their collected seeds with other gardeners. If you’re interested in participating in a seed exchange, look to community newsletters, local co-ops, and organic food stores; as they often play host to these events.
When collecting seed, consider choosing from plants that looked their best this year. Try to avoid collecting seeds from plants that are known to be hybrids. Lastly, be aware, that for many plants, the plants that will grow from your collected seeds, may not look exactly like the plants that grew the previous year.
There are two main types of seeds: dry seeds and those that come from moist fruit. Vegetables such as beans and ornamental plants such as cosmos or zinnias will produce dry seeds, which can be treated for disease, dried, and stored. Seed should always be harvested when dry. Those seeds that come from moist fruit, can be scooped out once the fruit has fully ripened, washed in a strainer, or sieved to remove any mucilage; then can be treated, dried, and stored. If dealing with squash or pumpkin seeds, a strainer alone will likely not be sufficient to remove the stringy mass that surrounds seeds.
After the collecting seed, it is very important to treat the seeds in order to reduce seedling infection or death caused by bacterial diseases like Xanthomonas and fungal diseases such as Alternaria. Seed treatments will vary by plant species. Plants like eggplant, tomato, pepper, carrot, spinach, lettuce, celery, cabbage, turnips, radishes, broccoli, and related vegetables should be treated with hot water. (See the following link for more details http://en.wikipedia.org/wiki/Cruciferous_vegetables). Vegetables like squash, gourds, pumpkins, watermelons, asparagus, as well as flowers like zinnias, should undergo a chlorine treatment.
Hot water treatmentPlace washed seed in a cotton bag, nylon bag, or wrap it in cheesecloth. Warm the seeds for about 10 minutes in a 100F (37C) degree water. Drop the bag into water that is 118-125 degrees Fahrenheit (47-51C) for 15-30 minutes, depending on treatment (See the following link for more details:
http://ohioline.osu.edu/hyg-fact/3000/pdf/3085.pdf ) . Place the bags of seed in cool water for about 5 minutes after the set period of time and then, place them on a screen or newspaper to dry.
Bleach TreatmentMake a solution of 20% bleach, 80% water, and surfactant (dish soap will be adequate). A simple way to do this is by mixing 1/4 cup bleach to 1 cup water, and then add a drop or two of dish soap to this mixture. Place the seeds in this solution for one minute and mix. Then pour this mixture through a strainer and rinse the seeds well with water. Place the seeds on newspaper or a screen and allow them to dry.
StorageWhen your seeds have completely dried, place them in paper bags or envelopes, label them properly, and store them in a cool, dry place. Adding a piece of paper towel or a napkin to the envelope or bag will help ensure dryness. You may choose to store the bags in the bottom drawer of your refrigerator. If you do this, you may wish to place all envelopes or paper bags in a plastic bag with 1-2 pieces of paper towel. This will ensure that if any spills occur, your seeds will be safe.
Another helpful web Source: