When saving seed, always harvest from the best. Choose disease-free plants with qualities you desire. Look for the most flavorful vegetables or beauitful flowers. Consider size, harvest time and other characteristics.
Always harvest mature seed. For example, cucumber seeds at the eating stage are not ripe and will not germinate if saved. You must allow the fruit and seed to fully mature. Because seed set reduces the vigor of the plant and discourages further fruit production, wait untill near the end of the season to save fruit for seed.
Seeds are mature or ripe when flowers are faded and dry or have puffy tops. Plants with pods, like beans, are ready when the pods are brown and dry. When seeds are ripe they usually turn from white to cream colored or light brown to dark brown. Collect the seed or fruits when most of the seed is ripe. Do not wait for everything to mature because you may lose most of the seed to birds or animals.
Beans, peas, onions, carrots, corn, most flowers and herb seeds are prepared by a dry method. Allow the seed to mature and dry as long as possible on the plant. Complete the drying process by spreading on a screen in a single layer in a well-ventilated dry location. As the seed dries the chaff or pods can be removed or blown gently away. An alternative method for extremely small or lightweight seed is putting the dry seed heads into paper bags that will catch the seed as it falls out.
Seed contained in fleshy fruits should be cleaned using the wet method. Tomatoes, melons, squash, cucumber and roses are prepared this way. Scoop the seed masses out of the fruit or lightly crush fruits. Put the seed mass and a small amount of warm water in a bucket or jar. Let the mix ferment for two to four days. Stir daily. The fermentation process kills viruses and separates the good seed from the bad seed and fruit pulp. After two to four days, the good viable seeds will sink to the bottom of the container while the pulp and bad seed float. Pour off the pulp, water, bad seed and mold. Spread the good seed on a screen or paper towel to dry.
Seeds must be stored dry. Place in glass jar or envelopes. Make sure you label all the containers or packages with the seed type or variety, and date. Put in the freezer for two days to kill pests. Then store in a cool dry location like a refrigerator. Seed that molds was not completely dry before storage.
Seed viability decreases over time. Parsley, onion, and sweet corn must be used the next year. Most seed should be used within three years.
Seed saving is essential for maintaining unusual or heritage vegetables and flowers. It is a great way to propagate many native plants too.