How to Convert (Part of) Your Lawn to Native Prairie
According to research estimates, lawns cover more than 40.4 million acres of land in the United States, making turfgrass our nation’s largest irrigated crop. That’s enough lawn to cover all of Illinois and then some. And speaking of the “prairie state,” did you know we have only 2,500 acres of prairie left in Illinois? That’s 0.01% of the 22 million acres that once blanketed the state.
All this is a complicated way to say: we have too many lawns and not enough prairies.
Lawns require a steady stream of (sometimes problematic) resources to keep them green and pristine—water, fertilizer, herbicide, and fuel for mowing (not to mention hours of your labor). They also provide very few ecological benefits to pollinators, wildlife and people.
A prairie garden, on the other hand, will provide food and shelter for pollinators, sequester more carbon underground in the deep roots of native prairie plants, and absorb more rainfall, helping divert stormwater from Chicago’s overwhelmed sewer system… and maybe your basement.
The Chicago area has several fine examples of native prairie types: black soil prairies, sand prairies, wet prairies, dolomite prairies and gravel hill prairies, as well as prairies reconstructed from former farmland (which often used to be prairie).
While your Chicago yard probably doesn’t have the right conditions for a gravel hill prairie, you can use the guide below to replace part (or all!) of your lawn with a mini-prairie adapted to your site.
Evaluate Conditions and Pick a Spot
Figuring out what type of light, soil and moisture conditions you have will help you choose the right spot (and plants) for your new prairie.
What kind of light do you get?
If you get enough sun to maintain a good lawn, you probably have the right light conditions for a good native prairie.
But to be sure, pick a day and observe your prospective prairie patch several times from sunrise to sunset, noting how much sun the area is getting. Is it sunny, shady, a mix, or dappled sun (sun filtered through trees or shrubs)? If the area is in the sun at least six hours over the course of the day, you have enough for a prairie.
Too much work? Look south and trace the path of the sun from east to west. Identify buildings, trees and other tall objects that will create shade and take an educated guess as to how much sun you are getting.
Note that the sun is lower in the sky in spring and fall, so a spot that is shady in April may be sunny by July.
What kind of soil and moisture conditions do you have?
Much of Chicago has soil with high clay content. Clay particles are small and fit together tightly, making clay soils slower to drain. Areas close to Lake Michigan tend to have well-draining sandy soils—sand particles are larger, leaving more room for water to filter through.
But when you live in an urban area, your soil could be… anything! Construction fill, long forgotten pea gravel, compacted aggregate rock, an entire concrete sidewalk—we’ve heard it all.
To make sure your site is suitable, you can dig one or more test holes six inches or so in depth. If you have compacted rock a few inches under your lawn, that’s something you’ll want to know before you remove turfgrass and purchase plants. When digging or planting deeper than a few inches, it is always a good idea to call 811 and get your underground utilities marked.
If you want some more specific answers about your soil and drainage, University of Illinois Extension has tips for quick soil tests you can do at home, along with links to more advanced soil testing resources. You can also do a simple test to see how quickly your site drains by digging a little deeper.
Too much work? Make some simple observations instead… Is the site near a downspout? Is it in a low spot in the yard? Does it receive stormwater runoff from a paved surface? Next time you get substantial rainfall, see where water collects in your yard (if it does at all). Over the next few days, see if the area is still wet or if it has dried out.
A low area with clay soil near a downspout could be a good place for prairie plants that love moisture, while a sandy area that stays dry will be ideal for our most drought-tolerant native plants.
Photo by Dano - CC BY 2.0
Removing or Killing the Turfgrass
Careful application of glyphosate during spring or fall is an effective way to kill turfgrass without disturbing the soil (and the weed seeds within), but there are many alternatives for organic-minded folks. Here are some herbicide-free methods for removing or killing the turfgrass on your future prairie site—consider your timeframe, abilities and budget when choosing a method.
Shovel and a workout
Using a flat shovel is the simplest (note that we didn’t say easiest) way to remove a patch of lawn. Give this area a good soak a few days before you remove the grass to make this process a bit easier.
Cut the outline of your prairie by pushing the shovel vertically into the ground about one or two inches—turfgrass has shallow roots, so you don’t need to go too deep.
Cut rows a couple feet wide through the site using the same technique.
Starting at the end of a row, push your shovel into the existing outline cut and pry the turfgrass up. Now move the shovel into a horizontal position and push/slice through the turfgrass roots, peeling the top one-ish inches from the soil below. It may be helpful to kneel for this.
Repeat the previous step on each row. You can either roll the turfgrass as you go, or cut it off in chunks.
You’ll be left with strips of sod that can be used elsewhere. If you aren’t reusing the sod we recommend shaking out as much soil as possible and composting the remaining material.
Sod cutter
Want to use machine power to remove the turfgrass? A sod cutter is a machine that automates the work of the shovel method (see above), leaving you with a clean site and strips of sod.
You can rent a sod cutter from a local home improvement store, but make sure you read the instructions carefully and educate yourself on how to use one safely. Keep in mind that using this machine can be its own sort of workout!
Solarization or occulation
When you have a longer timeframe (two to six weeks), solarization or occulation is a good option. Solarization involves using a clear tarp to cover the site to kill grass and other vegetation, while occulation uses a similar process with an opaque tarp.
The University of Minnesota Extension has a great guide to solarization and occulation to get you started.
A newly planted lawn to prairie conversion.
Preparing the Site for Planting
Your site preparation depends on the method you used to remove or kill your turfgrass. With Chicago’s clay soils and the compaction that occurs with foot traffic on lawns, we generally recommend working the soil at least a little before planting—but use your specific conditions (and preferences) as a guide.
If you removed the top layer of your lawn using a shovel or sod cutter, then the surface of your future prairie is an inch or two lower than the surrounding area. We recommend building the soil level back up with organic material, like mushroom compost (which will add nutrients and help improve drainage in clay soils).
Add enough compost to raise the soil level to match the surrounding area and then mix it with the existing soil to a depth of four to six inches—you can use manual tools like a cultivator, shovel and bow rake for this job. Level the site with a rake and you are ready to plant!
If you want to use some machine power to mix the compost and soil, you can rent a rototiller from a local home improvement store (same disclaimer about safety and reading directions). The rototiller breaks up and mixes soil to help prepare a new planting site. If you can handle a messier process, you can use it directly on your lawn and skip the previous turfgrass removal steps.
If you used the solarization or occulation method, you can plant directly into the dead grass, which keeps weed seeds from getting stirred up and germinating. If you like, you can add a bit of organic fertilizer directly into each planting hole.
Lawn to prairie conversion after two months.
Choosing Plants
Now that you’ve learned about your light, soil and moisture conditions and prepared your site, you can confidently choose plants that will thrive in your new prairie.
Visit Christy Webber Farm & Garden’s Native Plant department for a wide selection of native plants—we’d love to help you decide which plants to include in your new prairie! You can also order native plants from our online shop, which allows you to filter by light and moisture conditions.
Need more help? We offer native plant consultations in Chicago! Reach out to cooper.forsman@cwfng.com for details.
Here are some general tips when choosing plants:
Remember your conditions. Don’t forget to match plants to your light, soil and moisture conditions.
Consider height. Not all prairie plants are tall! Decide what will look good in your space—a short prairie, tall prairie, or mix of heights.
Note bloom times. To support our native pollinators (and have beautiful flowers to enjoy in each season) make sure to include plants that bloom in spring, summer and fall.
Don’t forget native grasses and sedges. Grasses and sedges are an essential part of our native prairies and provide important benefits for native insects and birds. And they are a great design element in a prairie planting.
Fully established lawn to prairie conversion.
Planting and Initial Care Tips
It’s time to put your plants in the ground! Some things to remember:
Don’t be afraid to crowd prairie plants. That’s how our native prairies function, and planting your prairie densely helps reduce weed competition. Take note of the spread of your new plants at maturity, but don’t be worried about overlap.
Mulch lightly, if at all. Mulching can help the soil retain moisture and slow weed competition, but more than a light layer of woody mulch (just enough to cover the surface) can be detrimental to your prairie’s growth. Once your prairie fills in, weeds won’t have much room to grow and dead plant material will serve as a natural (and free) mulch.
Consider height, bloom times and colors when placing plants. Keep shorter plants on edges, use tall plants as focal points and balance your blooms over the course of the growing season.
Water until established. Make sure to water your new prairie regularly in the first month or so after planting, and continue to water when needed through the first growing season (depending on weather conditions). Prairies planted in fall will require less initial watering. Once plants are thoroughly established (usually after one or two growing seasons) watering won’t be necessary, except during periods of prolonged drought.
Leave dead plant material up during winter. This gives pollinators a home for the winter and is infinitely more interesting to look at than bare ground. To keep pollinators happy, delay your garden clean up until late spring. When you do clean up, that dead plant material can be broken up and used as free mulch.
If all this seems like too much to take on—let us help! Come visit Christy Webber Farm & Garden’s Native Plant department or reach out to cooper.forsman@cwfng.com for details about our native plant consultations. We can also connect you with the local help you need to remove your turfgrass and plant your prairie.