Marigolds are a strong stock flower produced from a tiny seed. Their hardiness, ease of care and long growing season -- from spring to fall -- make them a natural teaching tool in grammar school science class. When fall arrives, a final circle-of-life lesson is made clear when students clip flower heads and dry their seeds to produce the next spring's crop of flowers.
Allow Seed Pod to Die
While dead-heading a marigold throughout its growing season will assure a hardy and well-flowering plant, when it's time to save seeds, it is best to allow the flower to die on the plant. However, it is also important for you to get to the seeds before the birds do or before frost kills them off entirely, so pay close attention to your seed harvest opportunity.
Harvest the Flower Head
Choose a sunny day to harvest your crop of marigold seeds. Select the pods that are the most mature on the plant. Use small garden shears to gently clip the heads off the plants. Be careful not to break the casings as you work. If you are collecting from a variety of marigold plants, be sure to keep them separate as you work.
Open the Seed Pod
Break the pod open and lay the seeds in a single layer on a flat, dry surface. Allow them to remain undisturbed for about a week. It's important that they're fully dry before you place them in winter storage.
Store in Labeled Envelopes
Once completely dry, place the seeds in paper envelopes, being sure to label different varieties. Do not use plastic, as moisture could form and kill the seeds with mold or bacteria. Store over the winter in a cool, dry location.
Uproot the Plant
After frost has killed off the marigold, pull it from the soil and dispose of it with your other compost materials.
Start your marigold plants from your saved seeds about two weeks before you will plant them in your garden, after the threat of frost has passed. Seeds take about three or four days to germinate.
Be Wary of Hybrids
Because so many of today's plants are hybrids, producing an exact replica of the plant from which you harvested can be an iffy science. However, you will still likely get a hardy version of the marigold that is a great garden border and sunny garden accessory.