Hydroseeding in Chicago, IL

Hydroseeding sprays grass seed, wood or paper mulch, fertilizer and a tackifier together in one wet slurry, so the seed lands already covered and held in place. In Chicago and its suburbs, that matters more than people expect. The city is built on ground that Wikipedia describes as naturally flat, rising less than a hundred feet from the lakeshore to the old moraine ridge at Blue Island on the far South Side. Out in the collar counties the land rolls more, but the soil underneath is mostly the same story: fine silt and clay left by glaciers. Water lingers on this ground. A dry-seeded lawn on bare clay is at the mercy of the next storm, while a hydroseeded lawn has a mulch blanket on it from the first hour.

What the soil is like here

The USDA's description of the Markham series, a soil first mapped in Lake County with its sample site in DuPage County, gives a good picture of a typical suburban yard: a dark silt loam topsoil only six to nine inches thick, then silty clay loam subsoil that runs 35 to 45 percent clay, sitting on very firm glacial till. The USDA rates its permeability as slow and notes a perched water table two to three and a half feet down in most springs. The Drummer soil, which Illinois adopted as its state soil, is darker and richer but rated poorly drained by nature, formed under prairie on loess over glacial drift.

What that means on a job: after a builder strips and regrades a lot, the thin black topsoil is often gone or buried, and the seed ends up sitting on compacted subsoil. We check that before anything else. If there is not enough topsoil to hold moisture and roots, we say so and price it, because seed on bare clay will come up thin no matter how it was applied.

Rain, heat and the seeding calendar

Chicago's 1991 to 2020 normals put annual precipitation at about 41 inches at Midway and 38 inches at O'Hare, with May the wettest month at both airports. Most of that rain comes in thunderstorms, and a heavy one on a freshly dry-seeded yard can push seed into low spots and leave bare streaks on any grade. Summers are hot and humid, with about 17 days in a normal year reaching 90 degrees, and spring and fall are short.

Lawns in this region are built from cool-season species, chiefly Kentucky bluegrass, perennial rye, and both tall and fine fescues. University of Illinois Extension says late summer to early fall is the ideal time to seed them, and for northern Illinois it narrows that to early August through early September. April is the second choice. Seeding in late spring through midsummer often runs into trouble because summer heat slows or stops these grasses. So when someone calls us in June, we can still spray, but we will be honest that the watering load is higher and the stand may need touching up in fall.

Sod, hydroseed or dry seed

All three can end up as a good lawn. Illinois Extension notes that if planting is done properly, a seeded lawn and a sodded lawn should end up the same; the differences are in cost, speed and risk.

• Sod is an instant lawn that can be walked on soon after it goes down and keeps mud and erosion down right away. It costs the most, comes in a limited choice of grasses, is not grown for shade, and needs a lot of water at first.
• Dry seed spread by hand or a spreader costs the least but is the easiest to lose. Extension lists rain or irrigation washing seed away, weeds and slow stand development as its weak points, and recommends straw over it.
• Hydroseed sits in between on price. Its fiber layer keeps the seed damp and pinned down on slopes and swales, and you can choose a seed mix for sun or shade. When warmth and moisture cooperate, sprouts usually show within 5 to 7 days, and four to six weeks is the typical wait before the mower comes out.

For most new Chicago-area lawns of a few thousand square feet or more, a hydroseed lawn is the practical middle path. For a tiny city front yard that has to look finished next week, sod may make more sense, and we will tell you that.

Construction sites, stormwater and erosion

Bare dirt on a building site is a stormwater problem as well as a landscaping one. Under the Illinois EPA's general stormwater permit, any project disturbing an acre or more needs coverage, and so does a smaller piece of a bigger phased development or subdivision; coverage needs a Storm Water Pollution Prevention Plan. In Cook County, the Metropolitan Water Reclamation District's Watershed Management Ordinance has applied to development since May 1, 2014, and soil erosion and sediment control is one of the things it regulates.

That is why our crews do more than spray grass. We install silt fence along the low side of a site, protect storm inlets, lay erosion control blankets in swales and ditches, and spray hydromulch or bonded fiber matrix on slopes to hold them until the grass takes over. Builders and site managers can hand us the plan sheet and we will work to it.

Getting the ground right first

A good stand starts below the seed. Before we spray, we look at grade, drainage and topsoil depth. On flat lots the most common problem is water standing near the house or in the middle of the yard, so a little yard grading to move it toward the street or a swale makes a bigger difference than any seed mix. Our grading crews also handle topsoil delivery and spreading, fine raking, and the small excavation and trenching jobs that go with drainage fixes.

For older lawns that have gone thin from shade, grubs, drought or foot traffic, a full renovation is not always needed. Core aeration and overseeding or a targeted hydroseed patch can bring them back, ideally in that same late summer window.

What to expect on spraying day and after

On the day we spray, the slurry goes on green so you can see the coverage, and it dries to a light mat within a day or so. From then on, watering is the job. University of Nebraska Extension suggests that on hot days newly hydroseeded ground get water at least two or three separate times daily, keeping the top of the soil damp but not puddled. On Chicago clay, puddling happens fast, so short and frequent beats long and heavy. We leave a written schedule and tell you when to switch to deeper, less frequent watering once the grass is up.

Keep people and pets off for the first few weeks, hold off on weed killers until the lawn has been mowed several times, and mow the first time when the grass reaches about three to three and a half inches. If you want to see what your yard would need, get a free estimate

We work in Chicago and out through Cook, DuPage, Will, Kane, McHenry, Lake and Kendall counties. Close in, Wheaton, Lisle and Bolingbrook mix established yards with drainage problems, wetland edges and teardown lots. Along the Fox River, Elgin, St. Charles, Aurora, Algonquin and Oswego have river-bank lots and subdivisions from every decade. To the southwest, Naperville, Plainfield, Romeoville, Lockport, Joliet, New Lenox, Minooka and Yorkville have flat, fast-growing ground and a lot of builder lawns that need seeding or rescuing. Lemont is hillier than most of the metro. In the north and northwest, Crystal Lake, Lake in the Hills, Huntley and Gurnee range from rolling hills to warehouse acreage, and Highland Park and Lake Forest have ravines, bluffs and big lawns at the edge of prairie preserves. Pick a town below for the soil, slope and drainage notes that apply there.