Snow seeding sweet spot
For more than 20 years, the Forest Preserve has been spreading literally tons of seed over hundreds of acres during winter to restore the plant diversity that once adorned the Will County landscape. Precious seeds are hand tossed or spread by tractors in January or February, not exactly what most people would expect what with spring planting so ingrained in the average gardener’s mind.
But snowy winter days are the perfect time to set this seed-to-sprout cycle in motion. And after experimenting with different times in the winter, Forest Preserve staff believe they have found the snow seeding sweet spot.
“We experimented with earlier and later in the winter and are now feeling like January or early February is the prime time to get the seed down, especially when the ground is frozen and there is light snow cover,” said Floyd Catchpole, land management program coordinator. “Snow cover hides the sown seeds so the plants can wait until spring to emerge.
“Seed planted in fall can be eaten by small mammals and bugs,” Catchpole explained. “In winter, the bugs are mostly dormant. And the seed often melts into the snow on a sunny day, making it hard for mammals to find.”
Even better is when additional snow falls and buries the seed, he added.
“The ground is broken up by the freeze/thaw cycle, and melting snow and rain washes the seeds into tiny cracks in the ground. Many seeds need exposure to winter temperatures, a process called stratification, before they can germinate in the spring. Nothing stratifies native seed better than being out in winter.”
Juli Mason, the Forest Preserve’s land management program coordinator, said this theory was proven recently when a contractor was hired to seed a former farm field in 2018. Part of the field was seeded during cold conditions in mid-February. Then the contractor’s tractor got stuck in the mud as it was clearing the field and it couldn’t be freed until spring. The rest of the seed was sowed in late March.
In the 2019 growing season, the difference was apparent, Mason wrote in an article for the Grassland Restoration Network. The area seeded in spring was dominated by foxtail, an annual grass that tends to fade quickly in restorations once the native plants get established. In contrast, the portion of the field that was originally seeded during the winter had a diversity of native plant species including: blue vervain, tall coreopsis, common boneset, sneezeweed, water horehound, black-eyed Susan and false boneset.
The message was clear, Mason wrote: “Don’t wait until spring to seed a diverse prairie mix, unless you want to give warm season grasses an advantage at the expense of diversity.”