Basics Steps for a Small(ish) Prairie Garden

Tallgrass Prairie Wildflowers

I have decided to turn a small, 10×30-foot section of road ditch on my property into a mini restored prairie garden.

Our house is in a semi-rural Iowa location and is surrounded by corn and soybean fields. All the riparian woodlands have been ripped out by the farmers, the fields are routinely sprayed with glyphosate and the field peripheries are regularly mowed.

Needless to say, there is very little habitat left for native plants, butterflies and other critters. I would like to change that a bit in my own small way.

I’ve looked around the web for guidance, and here are notes to myself on the basic steps for recreating a small patch of prairie. It’s by no means exhaustive, but I think it’s a good framework I can return to over and over, updating as needed, and searching the larger web for more detail.

My biggest takeaway for prairie restoration is that it is a multi-year project, with up to a decade sometimes before you reach full maturity. But I think the sight of those native wildflowers as I pull into the driveway will make it worth the while.

Choosing Your Prairie Seed

Prairie seed will generally be a mix of grasses and forbs. Forbs are the wildflowers that make prairies such a beautiful sight in the spring and summer.

There are quite a few outfits online to order from, and most will make custom mixes for you. Pick a seed mix that is designed for your region of the country and the type of soil you will be planting in.  I’m ordering from Prairie Seed Farms or Seed Savers Exchange because they’re both Iowa local.

Update: Here are shots of the two mixes I ended up buying: one forbs, the other grasses.

Mesic forb mix

Mesic grass mix

Types of Prairie

The three regional types of prairie in the U.S. are tallgrass, mixed grass and shortgrass. Tallgrass prairies are in the eastern plains, shortgrass in the western plains and mixed grass in the middle. Where we live in Iowa is historically tallgrass, so I’ll be planting a tallgrass mix.

Types of Prairie Soil

The three basic prairie soil types are wet, mesic and hill prairies. Soil type determines which species will do best in those conditions and what should be in your seed mix. Wet prairies are found in lowlands, along rivers and streams and swampy areas. Dry prairies are found on the tops of hills and in areas with quick, thorough drainage. Mesic prairies are in the middle and are the most diverse and rich in species. They are also the most threatened since most were plowed under to use as rich farmland. My patch is pretty mesic, so I’ll be planting a tallgrass mesic mix.

Preparing Your Prairie Patch

Plot Your Patch: Find a large space of turf grass with full sun and decent drainage. Measure out your plot, leaving enough space on the periphery for mowing and easy access. My patch is 10×30 feet, and I’m leaving about 3 or 4 feet of border on all sides.

Kill the Grass: In late spring or early summer, cut enough cardboard to cover the size of your plot. Lay the cardboard over the plot, overlapping it so no sun gets to the ground underneath. Secure the cardboard in place with stakes, heavy bricks or stone. Strew straw over the top for a more eye-pleasing look.

Add a Cover Crop: Once the grass underneath is fully dead — in early September or so — remove the cardboard and lightly till the plot. Seed with a cover crop (alfalfa, ryegrass, etc.).

Grid Your Plot: In mid-October, before it has a chance to go to seed, till under the cover crop. Cover the plot with straw. Grid off your patch with stakes and string in easy-to-manage sections of about 10×10 feet or thereabouts.

Spread Your Seed Mix: Mix your prairie seed mix with about 4 gallons of compost for each 500 square feet. Distribute the seed evenly over the straw, working in one grid square at a time. Don’t work the seed in. Winter freezing will work it in sufficiently.

Add Visual Variety: If you want patches of specific species (for visual effect), sow them separately over the top of your main mix where you would like them to grow.

Overwinter: Leave the patch alone over winter and let nature do its thing. Winter cold will naturally cold stratify the seeds (improving their viability and germination rate), and winter snows and rainfall will give them sufficient moisture.

First Year: In the spring, your seed will start growing, grasses first. Don’t weed for the first two years to avoid disturbing the tender seedlings. Mow or weed whack the patch every time it reaches 8 to 10 inches in height down to a height of 4 to 5 inches.

Second Year: Weed whack the patch regularly down to a height of 6 to 12 inches.

Third Year: Weed whack the patch regularly down to a height of 10 to 15 inches. Pull, cut out or carefully herbicide any unwanted non-native weeds.

Years Four through Seven: Burn 1/3 to 1/2 of your patch annually, leaving the rest for overwintering wildlife. Rotate to the remaining patch the next year. Burns should be done in March or April.

Years Eight and Beyond: Burn every 3 or 4 years to maintain.

Alternative to Prairie Burning

My patch is too small and too close to the road, our mailbox and other houses for safe burning. Plus, I just don’t trust my abilities to do it right. So instead of burning — but following the same schedule —  I will weed whack, then mow the patch down to about 2 to 4 inches. Once the patch is mowed, it’s important to rake it well to remove any remaining thatch.

I’ll be updating this post as I go, and feel free to leave a comment if you stumbled across it.

Update: Late July 2016

Here is a view of the patch with cardboard mulch laid down. It took me a few weeks to get all of the cardboard and bricks laid down. (I’m not exactly a spring chicken.) I planted a couple pumpkin vines and a watermelon in some holes I left to get some use out of the site in the meantime. Now…to wait.

Prairie garden patch with cardboard mulch to kill grass
Prairie garden patch with cardboard mulch to kill grass.

Update: Early October 2016

This is how the patch looked after I removed the cardboard mulch in early October. All of the grass was dead, and I raked off the top loose layer. Leaving a base coat to hold the seed over winter. I’m going to let it air for a couple weeks before spreading the seed. And by the way, the pumpkin and watermelon I planted on the spur of the moment gave me a bumper crop!

Prairie garden patch, mulch removed.
Prairie garden patch, mulch removed.