When is the best time to harvest seeds? The secret? A dry day, after the dew dries off. Afternoon is better than morning.
Throughout the growing season, observe your plants as they bloom and then set seed. Any flower that was will eventually have a seed to harvest in its place. Early spring ephemerals may set seed in May or June. Look for signs that the seeds are maturing. For example, Shooting Star seed capsules should turn brown some, such as the picture on the right side of this page. If the stem is turning brown, that is also a sign that the seeds are ready to be harvested. Wild Geranium and Columbine seeds will also mature in early summer, shortly after the flowers have stopped blooming. Sedges will flower and set seed throughout the spring and summer, so be observant and collect when you see the signs. Goldenrod, asters and most of the grasses, being later to bloom, may not be ready to harvest until September or even late October. As you collect seeds, place them into a brown paper bag, label the bag with the plant name and date and store in a dry area.
The Barrington Area Library hosted a How to Collect and Sow Native Plant Seed webinar on September 9, 2020 which was recorded and can be viewed on youTube. In this webinar, Sarah Michehl from The Land Conservancy of McHenry County discusses collecting and sowing native plant seeds. This is a great resource to learn basic seed identification, collection methods and timelines, and tips on how to sow.
The Lake County Seed Collection Guides are a wonderful resource for collecting native seed. These guides were developed by Dale Shields and Kelly Schultz from the Lake County Native Seed Nursery and have been submitted and posted with the Field Museum Field Guides collection. Here are links to these guides:
Illinois – Lake County Seed Collection Guide – Woody Plants
Illinois – Lake County Seed Collection Guide – Spring Woodland Forbs
Illinois – Lake County Seed Collection Guide – Summer Woodland Forbs
Illinois – Lake County Seed Collection Guide – Summer Wetland Grasses and Kin
Illinois – Lake County Seed Collection Guide – Summer Wetland Forbs
Illinois – Lake County Seed Collection Guide – Summer Prairie Forbs
Illinois – Lake County Seed Collection Guide – Summer Grasses and Kin
Illinois – Lake County Seed Collection Guide – Asters and Goldenrods
Illinois – Lake County Seed Collection Guide – Fall Woodland Forbs
Illinois – Lake County Seed Collection Guide – Fall Wetland and Forbs
Illinois – Lake County Seed Collection Guide – Fall Grasses and Kin
Illinois – Lake County Seed Collection Guide – Fall Prairie Forbs
The Field Museum Field Guide, Illinois – Seed Heads of Common Native Plants of the Tallgrass Prairie Region is also a great resource to show you what the common native plant seed heads look like at maturity.
You can find a great list of Seed Collecting Dates on the Pleasant Valley Conservancy website.
One of our chapter’s most popular events is the Annual Seed Exchange. Our 2022 Seed Exchange will take place on Saturday, November 12th from 10am to 1 pm at The Growing Place in Aurora. For more information on the event click here. You are welcome to bring your packaged and labeled seeds to exchange for others. FYI, if you manage a nature preserve, be aware that members and friends bring seeds collected in their home gardens, so we cannot document the provenance of these plants, be it from a local nursery or somewhere outside our growing zone.
Here is a list of species that were available at our 2021 Seed Exchange.