Native plant seeds are drying and ready for collecting! First things first, always get permission from those who manage or own the site or garden. People are often happy to share seeds, but always best to ask first. This is especially true on public land, such as parks. Find the park manager or ranger to get permission before you collect anything.
Next, make sure you have confirmed the plant identification, so you know what you are collecting. The MN SEED Project team really loves iNaturalist, a free app that you can use on your phone or computer. The AI (artificial intelligence) will often give you suggestions and a best guess but then the identification is also crowdsourced by experts in your geographic area. You can get started with this free iNaturalist orientation.
Once you know what plant you have, label your container (we recommend little yellow coin envelopes) with important information such as:
- Common name
- Scientific name
- Collection date
- Estimated number of plants collected from
- Your name or initials as the harvester
We like paper envelopes or bags best for collecting. Glass and plastic can trap moisture and cause the seeds to mold. We also like storing desiccant packets (just one or two, too many can dry out seeds) in with the seeds to prevent moisture and molding.
We recommend that you only collect 20% (or one out of every five seed heads). This leaves plenty for wildlife and for seeds to naturally disperse and reseed in place.
As you are collecting, make sure to watch where you walk and stay on the path or walkway so that you don’t squish any plants. When you’re done collecting, clean up the site so there’s no evidence you were there.
When you harvest seeds, it's important to make sure the seeds are mature, dry and ready for harvest. A key to this for many species means that the seeds will easily strip away from the plants when they are ripe. This is especially true for grasses. Grasses that aren’t mature won’t fall away from the stems—see this video example of harvesting Sideoats Grama.
A good test for seed maturity is to try and dent the seed with your fingernail. If the seeds can be dented, they are not yet ripe. If they are hard and don’t dent, they are likely ripe.
Other seed heads that will easily fall away from the stem or seed head when ripe are plants like golden alexander, prairie clovers, sneezeweed, cup and compass plants and non-Echinacea coneflowers like Ratibidas and Rudbeckias. With these, you can simply rub the seeds against your palm to break apart the seeds from the seed head.
Seeds of purple coneflower and rattlesnake master have spikey seed heads that are best harvested when they turn dark brown/black. Cut seed heads off the plant, put them in a cylindrical container (take-out containers work great), put the lid on and shake vigorously. Pro tip: save your fingers and add a rock to help if the seed head doesn’t easily break apart on its own. Further sifting will be needed to remove the seeds from the chaff, but this is the first step.
Plants will often hold onto their seeds, and you can harvest them easily by shaking the seeds into a container or envelope. Try this method with Monarda and Hyssop since they have tiny seeds. Obedient plant and Canada milkvetch both have larger seeds, but this same method can work well.
Legumes like Canada milkvetch have pods that seeds can be shaken free from, or they can be cracked open to release the seeds. Other legumes like wild indigos, partridge pea, leadplant, lupine, and wild senna all have pods that are easy to break open and even use the shells to scoop out the seeds if needed. Also, legume seeds can host weevil eggs, so we recommend putting them in the freezer as soon as you’ve harvested them for at least a week to prevent them from hatching and ruining your seeds.
Milkweeds are the other podded seedhead. They are best when they have started to turn brown and are just starting to crack open. At that point its best to hold the pod open side up and gently flex the pod back and forth with your thumbs and forefingers to loosen the seeds. Then you can open the pod and use your thumb to hold the feathery down in place and pour the seeds out the fat end of the pod.
Make sure you are storing seeds in a cool, dry, dark place. After the seeds are dry and processed, they can go in airtight containers. Before you plant check to see if there are any specific seed treatments needed. Prairie Moon is an excellent source for this information. For each species there is a germination code listed under the details section with a link to the requirements for that seed type.
MN Seed also has a great free webinar on growing natives from seed that was done by David Woods of Urban Roots if you're ready to take the step towards growing these seeds.
Thanks to Capitol Region Watershed District for funding the MN SEED Project’s activities in 2021 and 2022. The videos linked to in this post were all created at their headquarters in St. Paul with permission.
To learn more about the MN SEED Project visit northerngardener.org/mn-seed-project.
Hort society community programs director Courtney Tchida has a degree in Environmental Horticulture, a master's in Agricultural Education and a certificate in Permaculture Design. For 16 years, she managed Cornercopia, the University of Minnesota's student-run organic farm.
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