Updated: Jul 22, 2018
Collecting seeds is fun, and it gives you an opportunity to fill your garden with your favorite plants in a very economical way.
Setting seed is part of the life cycle of plants, and the way most plants are propagated in Nature. Most plants grow from seed, attain their mature size, flower, set seed and then die. This happens every season for annual plants; with perennial plants, this process may occur for several years until the plant dies.
Carefully choose plants to collect seed from. You want the most vigorous and attractive, or the one with the flower color that you just loved. Choose plants that are heirloom or open pollinated; those that are hybrids will either be sterile or not come true.
Recognizing when it’s time to collect seeds is important. Too soon and the seeds will not have matured sufficiently to germinate; too late and the seeds may be dispersed by the plant.
Some plants produce seeds in the flower head, other produce seeds in pods, and still other plants produce seeds in fleshy fruits. Seeds are most viable at the end of the season as the plant is getting ready to complete its life cycle. Once the flowers begin to fade and turn brown, most flower seeds are ready to be collected. Once seed pods have changed from green to brown, they are ready to be collected. Fleshy fruits can be removed from the plant any time they have set as they will continue to dry when they are removed. Use clean, sharp scissors or pruners to remove the flower heads and seed pods; fleshy fruits can be plucked by hand.
Collect seed on a sunny and dry day. Have paper bags and a marker at hand to identify what you’ve collected. Remove the seeds from the bag and place the flowers/pods on several layers of paper towel or newspaper and allow to dry completely (at least one week). Write the name of the seeds on the paper so that you don’t have to rely on your memory to know what they are.
Seeds that are enclosed in pulp (like tomatoes) need special processing. Scoop out the seeds and pulp into a cup and add two tablespoons of water to the cup. Cover the cup with plastic wrap and then poke a few holes in the plastic wrap. Place the cup in a warm place and allow it to ferment for several days. When scum has collected on the top, the fermentation process should have separated the seeds from the pulp. Carefully remove the scum and then pour the seeds, water and pulp into a strainer and rinse well to wash away the remaining pulp. Remove the seeds from the strainer and place them on several layers of paper towel or newspaper until completely dry; this could take up to two weeks.
Storage of seeds is important so they will be ready for planting next season. Once completely dry, remove the seeds from the flower heads or pods and place in paper coin envelopes or small paper bags. If you are using plastic pill bottles, be sure to place a drying agent in each container. Label and store in a cool, dry, dark place.
It’s important to keep seeds dry at all times as humidity and warmth shorten a seed’s life. The refrigerator is a good place to store seeds, but avoid the freezer. An efficient way of storing seeds in the refrigerator is to place several packets in a mason jar and then include a silica gel packet (or dried milk wrapped in paper towel) to absorb any moisture.
Keep in mind that not all the seeds will germinate. Even with commercial seed production, the seed packet will indicate the percent of germination to be expected (it’s rarely 100%), and some seeds naturally have low germination rates.
Quite a few seeds resist germinating without special treatment. Cold stratification is the process of subjecting seed to both cold and moist conditions. In Nature this occurs naturally when seeds drop to the ground in fall and overwinter outside. We can replicate this process by putting seed and moist sand/vermiculate in a plastic bag and storing it in the freezer. After the recommended period of time (one to three months depending on the variety of plant), the seeds can be removed and sown.
Scarification is required for seeds that have hard seed coats. The seed coat has to be compromised so that the seed can absorb water and start the process of germination. In Nature this occurs by being cracked by the pressure of the soil, or passing through the digestive tract of animals. We can help this process along by rubbing the seed with a file or sandpaper, nicking the seed with a knife (very carefully), or gently tapping the seed with a hammer. Some seeds require exposure to fire to germinate. A simple way of softening the seed coat is to freeze the seed overnight and then soak in warm water overnight.
There are other types of dormancy that may have to be overcome for seeds to germinate, but these are the most common. I always recommend that a reliable resource be consulted before sowing seeds to determine if they require special processing.
Most seeds will remain viable for up to two years, so if you don’t need the hundred tomato seeds that you collected, share with friends. Encourage them to save seeds too and then everyone benefits.
Don’t limit yourself to the plants in your garden. If you have eaten the best tomato or melon you’ve ever tasted, save the seeds and grow them in your garden next year.
And when you’re ready to sow seeds, don’t forget to check out my blog published September 10, 2016, (Starting Plants from Seed) for a refresher course.