Over the past few weeks, gardeners may have noticed a lot of plants going to seed. If you want your plants to look just as good next year, you could save the seeds of your favorites.

Seed saving is a popular method for increasing and sharing favorite garden plants. Quite a few annuals, perennials, vegetables, herbs and vines can be propagated by seeds that are saved and replanted. To get started, collect mature, dry seeds or pods from plants that have the characteristics you find desirable. Always store collected seeds in a cool, dry location until it is time to plant and label your collection to avoid confusion next season.

Heirloom vegetable seeds are great examples of how gardeners have preserved their favorite plant varieties by saving and passing down seeds over generations. Many seed companies now offer heirloom seeds of favorite vegetable crops.

It is important to note that some crops are not suitable for seed saving because they are hybrids of two varieties that are crossed by humans, creating a unique set of traits. Seeds from hybridized plants such as “Sun Gold” or “Big Boy” tomatoes are not likely to produce as pure a form of the plant as you would get from seeds you purchase.

Nonhybridized tomatoes, however, are among the easiest plants to save seeds from since it is easy to tell when the seeds are mature. When a tomato is ripe, you can be sure the seeds also are mature. Other commonly saved vegetable seeds are lettuce, beans, peas, peppers and eggplant. These plants are primarily self-pollinated, which means there is little chance of cross-pollination by insects or wind, although as in all things in nature, it can happen!

With a little more work, it is possible to save seeds from other vegetables. Spacing crops several feet apart, interplanting between crops with other flowering plants to waylay pollinators, and placing mesh cages over crops are some ways plant breeders avoid cross-pollination. Corn, Swiss chard, cucumbers, pumpkins, squash and beets are all examples of vegetables that require extra steps to keep their seed lines pure.

Collecting and saving seeds from ornamental flowers and vines is fun and rewarding. One of my favorite plants is the Moonflower Vine (Ipomoea alba), a fragrant white flowering annual vine with dinner plate-size flowers that open at dusk and wilt as the morning heat rises. They are prolific summer bloomers that are frantically pollinated by moths, resulting in lots of dark brown seed pods.

Collect the whole pods on a dry day, in paper or glassine envelopes, which make great containers. Avoid plastic bags, which can cause moisture to accumulate and ruin your seeds. Soak Moonflower Vine seeds in warm water to soften the seed coat before planting next spring.

Now is a good time to scout the landscape for summer annuals that have gone to seed. Marigolds, cosmos, cleome, zinnias, coleus and impatiens all fall in this category. Many annual flowers self-sow, popping up all over the garden. It is not necessary to collect these seeds unless you want to relocate them or share them with a friend.

Perennial flowering plants such as daylilies, hibiscus, coneflowers and black-eyed Susans also can be started from seed. Seeds that are saved from perennial plants typically need some exposure to cold temperatures prior to germinating.

This process is called stratification and allows gardeners to reproduce the conditions found in the garden as if the seeds were left to drop on the soil and sprout on their own.

Seeds can be pretreated by placing them in the refrigerator or by starting them in the fall and allowing them to grow outdoors.

Remember that many popular annuals and perennials are also hybrids, and although seeds can be saved, you are unlikely to get the same desirable characteristic the next season.

For example, daylilies almost never come back true to type from seed, but it’s interesting to see what flower color and form do come up!

Small seeds such as those found on basil and dill can be saved by placing a dry paper bag over the spent flowers.

Cut the stalk of the flowers and upend the seed heads into the bag.

A good shake should loosen the seeds without sending them flying everywhere! Be sure to label the bag and store in a cool, dry location until ready to plant.

Seed saving is certainly more labor intensive than simply purchasing a pack of seeds or a containerized plant, but seed saving can become a social outlet!

If you want to increase the diversity of plants in your garden for free, try a local plant swap, where gardeners gather to trade plants and seeds with one another.

The North Charleston Plant Swap is Sept. 22 near the gazebo at Park Circle.

If you want more information about this event, contact Darren Sheriff at thecitrusguy@netzero.com, or find it on Facebook under “North Charleston Plant Swap.”

Amy L. Dabbs is the urban horticulture extension agent and tri-county Master Gardener coordinator for the Clemson University Cooperative Extension. Send questions to gardening@postandcourier.com.