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Winter Sowers Bring May Flowers

The calendar has turned to December, and with the exception of the occasional stray dandelion on a south-facing slope, all of the flowers have wrapped up their anthers for the 2023 season.

But out on the prairie, the skeletons of last year's growth still have a few vestiges of life clinging to their frost-nipped tips in the form of seeds. Over the course of the winter, these seeds will gradually drop off or get plucked by birds or shaken loose by some other passing critter.

Dormant prairie near Volga, IA

With a little luck, that seed will land somewhere that it can achieve good contact with the dirt and, come next spring, spit out a radicle and join the fray with the rest of its botanical cohorts.

The continued freezing and thawing of winter along the Upper Mississippi will allow the soil to expand and contract, forming fissures for the seed to work its way into by the force of gravity. The earth will open up and suck the seed in, the shape and size of the seed carefully crafted by millennia of evolution to passively "drill" itself to just the right depth.

Some seeds, like those of Culver's Root, will need light to awaken. A winter of weathering will slowly break down the seed coat to the point where sunlight stimulates germination.

Most will not need light, but they still need time. "Moist stratification" refers to the amount of time a seed must spend in damp soil, just above freezing, before the seed will readily germinate.

The time needed for "moist stratification" varies wildly between species. Some need 10 days, some 30, some even need "double dormancy," like walnuts, which often require two full winters before breaking down enough to sprout.

Much ink has been spilled trying to help plant lovers make sense of this survival strategy in their efforts to grow plants. People fill ziplocks with seeds and peat moss, moving it in and out of the freezer and misting it with water when it dries out throughout the winter trying to simulate natural freeze-thaw cycles.

But more and more green thumbs have decided to work smarter, not harder, with a technique called winter sowing.

The logic is simple: native plants are adapted to the natural winter cycles, despite the seeming unpredictability of Iowa's winters. If a plant needs 30 days of cool, moist stratification, and seeds ripen in October, it will probably get those 30 days somewhere between now and next March.

Likewise, rather than attempting to abide the proper depth requirements that can vary considerably between species, simply sowing the seeds on the surface of the soil and letting those natural cycles work the seed to its own ideal depth, one can do away with the faded lines on their garden trowel and let the seed decide.

The curious shape of Spiderwort seed

The one caveat for true winter sowing comes in the vessel. Most practitioners use a plastic milk jug, or an old salad container, and leverage some of the "greenhouse effect" provided by the plastic to give the plants a slightly earlier start and more consistent humidity in those vulnerable early stages.

Once the plants sprout and reach a height of a few inches, they can be transplanted either into the ground or to a more robust pot to stretch their legs during the growing season.

Baby seedlings ready for bigger pots

We have done several "dormant seedings" of prairie plants over the last five years or so, the large-scale version of winter sowing (without a greenhouse, of course). We broadcast about this time of year, timed before a good snowfall to protect the seed from birds, and let nature do its thing.

My winter-seeded backyard prairie

But this was the first year I tried a more horticultural version at home. I had gathered a number of seeds in the fall of 2022, stored them in the fridge (or, in the case of some ironweed, forgotten to ever take them out of the back of my car), and kept them in the fridge. For Christmas my wife got me a few trays of Cone-tainers, which I'd heard gave deep-rooted natives a much better survival rate than the typical 2-3" deep plant cells sold at most garden centers.

Paavo posing with the cone-tainers

I got some high-quality potting soil designed for native plants, and excitedly started making a mess in my basement filling 200 cells with dirt. Once I'd prepped the cells, I stuck some seeds on top, took the whole works outside, and buried it all in the snow.

...And that was it. I wouldn't say I didn't think about them again - I think about plants almost constantly - but I didn't have to fiddle with them any more.

What mattered is that for a relatively small sum, I had a whole new garden growing on my deck. No fertilizer, no monkeying with pulling things in or out of the fridge and freezer, no "hardening off," just a bunch of plants readily growing and suited to whatever nature threw at them. Had it not been a particularly vicious drought year I'm not sure they'd have even needed much watering - I didn't offer any extra until mid-July or so.

Now this is still gardening after all, so not everybody made it, but I was thrilled. I had seeded several parts of my yard with prairie and/or savanna seed mixes in previous years, but it was up to the plant gods to decide which species would emerge. Here I had specifically chosen some species that stubbornly refused to show up in the mix, in the hopes of introducing more robust individuals who already had a head start.

The ironweed and leadplant, after some careful nurturing, went in the ground just before thanksgiving, their scraggly upper portions belying the considerable root systems they'd hidden in the cone-tainers.

Sprigs of junegrass, a prairie icon I'd paid for half a dozen times but never seen grow, dotted the edge of my plantings and senesced peacefully with the rest of the prairie.

I actually ran out of space for all the seedlings of show-stopping large-flowered foxglove, and had to begrudgingly let my wife put some in her garden. Their parent plant produced another copious crop this summer, but I opted not to collect quite so many seeds this year.

When it was all said and done, I couldn't believe how easy it was. Aside from a little bit of midsummer watering I hadn't had to do almost anything besides scatter some seeds on top and try to keep critters off the deck. I thought of my parents, both gardeners, who had fussed almost constantly with their plants growing up.

To be sure, their particular style of gardening had a few more variables since it featured lots of ornamentals and vegetables. But there's a definite smug satisfaction in having a yard full of plants that I grew, feeding butterflies and bees and costing me very little in time or materials.

For extra smugness, I can relish in the fact that I personally picked most of these seeds (with permission), so I know their origin. I know they're familiar with the local weather and soils.

Winecup, a hard-to-buy native that I hand collected this fall

My maternal grandfather, supposedly, had a legendary garden in the small town of Hanover, Illinois. My mom always spoke about how people would drive from all over to come and see it.

I never got to see it as he passed before I was born, but whenever I stick a trowel in the ground I think about him. I hope against hope that just a little smudge of his green thumb found its way down to me, and that I can continue using winter sowing to help more prairie plants find their way to new locales.

Looking Back

O.W.L.S. wrapped up the 2023 session with a visit to the Richardson-Jakway historic site on November 16th. The site, featuring a home built by Abiathar Richardson in 1849, is today a popular site for history buffs and nature lovers alike (thanks to the nearby Jakway Woods), making it a fitting end for this year's O.W.L.S. theme of "Iowa: Then and Now."

The Motor Mill Bridge Lighting saw the hard work of the Motor Mill Elves come to fruition on November 18th. If you missed the official opening festivities, don't worry, the lights will be on nightly until the end of the year so make sure to take an evening cruise and enjoy the


We've also had a fair bit of noise going on around HQ this month; Ray's Excavating has continued moving dirt around for the new campground here at Osborne, and Dan Jones Logging has been helping us meet the area sensitivity requirements for grassland birds by clearing an old overgrown fenceline on the north side of the park! Things will look different when all is said and done, but then again the only constant in nature is change.

Looking southeast from the archery range at two newly-connected prairie parcels

Looking Forward

Thursday, December 7th we will once again deck the halls for our annual Holiday Walk here at Osborne! This year will see a colorful cast revisiting the ideas told in 1972's The Lorax, an eco-classic who's lessons resonate even 50 years later - but what might Suess have written if he'd penned it today? Come on out to find out! Also a reminder as we get into second shotgun season that shotgun hunting is permitted at the following parks: Becker East & West Wildlife Areas, and the Pleasant Ridge Wildlife Area. All other parks prohibit shotgun hunting; please report any suspicious activity and be cautious when using huntable areas in season! Last but not least, if you're looking for a quiet getaway this winter, have we got the deal for you! We're offering Buy One Get One stays at the Motor Mill Inn from January 1st-April 30th! In other words, get yourself a whole weekend of solitude for the price of a Friday night. And if you haven't seen the Mill site in winter, boy are you in for a treat...

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