Winter sowing native seeds is an easy process that requires no special equipment, and the best part of propagating native plants from seeds is that it promotes genetic diversity for a more resilient ecosystem. To share her methods for simple winter sowing, my guest for this encore presentation is Heather McCargo, the executive director of the Wild Seed Project.
A Maine resident today, Heather grew up in Western Pennsylvania, where her mother was an organic gardener and naturalist. Heather spent her time outdoors playing in the woods, fields, wetlands and stream sides and is a self-described “child of nature.” She studied plant ecology in college and did several horticultural internships, getting hands-on experience. She apprenticed under Jack Alexander, the propagator at the Arnold Arboretum of Harvard University in Boston, who taught her the many methods used to encourage seeds to germinate.
Depending on the variety of seed, filing the seed coat or exposing it to a lit match or boiling water will aid germination, though Heather says Jack Alexander taught her that the simplest, most effective method of all is to just throw the seeds outside. Freezing and thawing between winter and spring will trigger germination in the seeds with no human intervention needed.
Heather says propagating native plants is economical and rewarding. What is time-consuming is collecting, cleaning and processing wild seeds, but, she says, conveniently, a lot of fun. She started the Wild Seed Project, a nonprofit organization, to gather a team of volunteers to do this important work.
For a comprehensive recap of my conversation with Heather, including her instructions for starting native seeds, you can check out the show notes from the original airing.
While you’re here, I want to take a second to remind you that I have a new book out, “The Vegetable Gardening Book: Your complete guide to growing an edible organic garden from seed to harvest.” It’s chock full of insider tips and new-to-you information that will help you step up your gardening game and tackle challenges.
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Native Seeds Are Easier to Work With
Heather endeavored to mimic natural, outdoor germination. She says sowing native seeds is much easier than raising domesticated and cultivated plants, which require compost, manure and weeding to thrive. Because native plants are adapted to our native soils, they don’t need the extra fertility that cultivated plants do. Native plants are much more resilient and vigorous.
Various native plants have their own soil requirements — some like dry, sandy, gravelly soil, some like hot, baking clay, and others prefer wet or medium moisture soil — but they are overall less fussy than cultivated plants.
Why Native Seeds Should Be Sown in Pots
Heather says in New England seed sowing is an activity for over the winter holidays, when other outdoor gardening jobs are finished. In warmer climates, the timetable is different but the steps are the same. Rather than just tossing seeds out into the landscape, she suggests sowing them in pots. This greatly increases the seeds’ chance of germinating and growing into adult plants.
“Everybody wants to just toss the seeds out into the landscape, but what that doesn’t take into account is the dangerous life of a seed,” Heather says. One plant can produce millions of seeds over its lifetime, she points out, but most will be eaten by birds and mice.
A small pinch of native seeds sown in pots will have a much greater chance of surviving to germinate. Clay pots work best because they are porous, while plastic pots hold water and don’t breathe and fiber pots that are designed to decompose are not a good choice because the plants grow slowly.
Preservation of Genetic Diversity
The native seed movement is designed to broaden the genetic diversity of native plants. Seeds are the result of two or more plants being cross-pollinated, so each seed is a unique individual. The genetics are the raw material that allows plants to adapt.
Heather says seed sowing was a missing link in the native plant movement, according to Heather. Nurseries typically clone plants, which means they propagate genetically identical plants by rooting cuttings, and they select the plants that they deem to be superior. But she explains that while those selections may look nicer to us, they are often not superior in providing ecosystem services to insects, birds and other creatures.
Plants with interesting colors and larger or doubled flowers are more appealing to humans but they are often sexually dysfunctional, which means they provide no nectar, pollen and seed, Heather says.
I hope you enjoyed my conversation with Heather McCargo and learned something new about winter sowing. If you haven’t listened yet, you can do so now by scrolling to the top of the page and clicking the Play icon in the green bar under the page title.
What seeds have you germinated successfully via winter sowing? Let us know in the comments below.
Links & Resources
Some product links in this guide are affiliate links. See full disclosure below.
joegardener Online Gardening Academy™: Popular courses on gardening fundamentals; managing pests, diseases & weeds; seed starting and more.
joegardener Online Gardening Academy Organic Vegetable Gardening: My new premium online course membership opens in 2023. Sign up for the waitlist here.
joegardener Online Gardening Academy Beginning Gardener Fundamentals: Essential principles to know to create a thriving garden.
joegardener Online Gardening Academy Growing Epic Tomatoes: Learn how to grow epic tomatoes with Joe Lamp’l and Craig LeHoullier.
joegardener Online Gardening Academy Master Pests, Diseases & Weeds: Learn the proactive steps to take to manage pests, diseases and weeds for a more successful garden with a lot less frustration. Just $47 for lifetime access!
joegardener Online Gardening Academy Perfect Soil Recipe Master Class: Learn how to create the perfect soil environment for thriving plants.
“Native Trees for Northeast Landscapes: A Wild Seed Project Guide” by Heather McCargo and Anna Fialkoff
“Native Plants for Roadside Restoration” by Heather McCargo
Arnold Arboretum of Harvard University
Disclosure: Some product links in this guide are affiliate links, which means we get a commission if you purchase. However, none of the prices of these resources have been increased to compensate us, and compensation is not an influencing factor on their inclusion here. The selection of all items featured in this post and podcast were based solely on merit and in no way influenced by any affiliate or financial incentive, or contractual relationship. At the time of this writing, Joe Lamp’l has professional relationships with the following companies who may have products included in this post and podcast: Rain Bird, Corona Tools, AeroGarden, Milorganite, Soil3, Greenhouse Megastore, PittMoss, Territorial Seed Company, Earth’s Ally, National Wildlife Federation and TerraThrive. These companies are either Brand Partners of joegardener.com and/or advertise on our website. However, we receive no additional compensation from the sales or promotion of their product through this guide. The inclusion of any products mentioned within this post is entirely independent and exclusive of any relationship.