Lawn aeration cost

Core aeration costs $100 to $250 for a typical 5,000 square foot lawn, typically around $160, for one pass of a machine that pulls plugs of soil out of the ground. Combined with overseeding the same visit is $250 to $550. A quarter-acre lot in Illinois, aerated and overseeded in September, is usually $350 to $600.

Most lawns do not need it every year. Aeration fixes compaction, and compaction lives in clay soil, in lawns that take heavy foot traffic, and in lawns laid over a construction site. A sandy lawn that nobody walks on is paying for holes it does not need.

What it costs

Lot size moves the price less than you would expect, because much of the cost is the trip and unloading the machine. Tight gates, slopes and lots of obstacles push toward the top of each range.

Core or spike

Core aeration uses hollow tines that pull out plugs of soil two to three inches long, about a plug every two to four inches across the lawn. It removes soil, which is the point: the surrounding soil relaxes into the hole, and air, water and fertilizer reach the roots.

Spike aeration pushes a solid tine into the ground. It removes nothing and presses the soil at the sides of each hole tighter, which on clay makes compaction slightly worse. It is cheaper for a reason.

Spike shoes and the spike rollers sold for towing behind a garden tractor do essentially nothing useful on a compacted lawn. If a quote says aeration without saying core, ask.

Does your lawn need it

The screwdriver test. Push a long screwdriver into moist soil. If it will not go in six inches without real effort, the soil is compacted.

Water that pools or runs off after a normal sprinkler cycle, rather than soaking in.

Thatch over half an inch. Cut a small wedge out of the lawn. A spongy brown layer between the green blades and the soil thicker than half an inch blocks water and fertilizer.

Thin, patchy grass in the areas people and dogs use most, while the edges look fine.

A rough schedule:

• Clay soil with traffic: every year
• Loam or a new-build lawn: every one to two years for the first few years, then every two to three
• Sandy soil, light use: rarely, and only if one of the signs above appears

If standing water stays for days after rain, the problem is more likely grading than compaction, and aeration will not fix it. See yard grading.

When to do it

Cool-season lawns of tall fescue, bluegrass and ryegrass: early fall, from late August to early October. The grass is growing strongly, weeds are slowing down, and it is the right time to overseed. Spring is a second choice.

Warm-season lawns of Bermuda, zoysia and St Augustine: late spring to early summer, once the grass has fully greened up and is actively growing.

Never in a drought or while the grass is dormant, because the lawn cannot recover from the damage.

The soil has to be moist. Dry clay bounces the tines out and the plugs come up an inch long, which is a visit wasted. Aerate a day or two after rain, or water about an inch the day before.

Fall is the busy season. Book in July or August, since good companies fill their September calendars early and late bookings get pushed into October.

Aeration with overseeding

Aeration is the best preparation for overseeding there is. Seed dropped over the lawn falls into the holes and into the loosened soil around them, where it gets the soil contact it needs, and germination is far better than on a lawn that was not aerated.

The combination costs $250 to $550 on a typical lawn, and it is what turns a thin lawn thick again. It needs:

• Light watering once or twice a day for two to three weeks, to keep the top half inch moist
• No pre-emergent weed control within about eight weeks either side, because it stops grass seed as well as crabgrass
• A normal mowing height, and no mowing until the new grass is about three inches tall

Where the lawn is bare soil rather than thin grass, overseeding is the wrong tool and a new lawn is the job, by hydroseeding or sod.

Fall fertilizer applied after aeration reaches the roots well, which is why treatment companies schedule the two together. The program itself is covered in lawn fertilization costs.

Frequently asked questions

Should I pick up the soil plugs left on the lawn after aeration?

No. They look untidy for a week or two, then break down with rain and mowing and return the soil to the surface, where it helps decompose thatch. Raking them up takes hours and removes the benefit.

How do I mark sprinkler heads and dog fence wire before the aerator arrives?

Push a small flag next to every sprinkler head, valve box and shallow cable, and tell the crew where an invisible dog fence runs. Tines go two to three inches deep and will crack a head or cut a buried wire. A good crew asks about this before starting, and most will not pay for a head that was not marked.

Is it worth splitting a core aerator rental with a neighbor?

Often, yes. A day's rental is $90 to $150, and a typical lawn takes an hour or two, so two or three households can share one day. The catch is the machine: it weighs 200 to 300 pounds, needs a pickup or trailer and two people to load, and pulls hard on a slope. Against a $160 professional visit, the saving for one lawn is small.

Can I aerate in spring if I have put down crabgrass preventer?

You can, and it is not ideal. Aeration punches through the barrier the pre-emergent forms at the soil surface, which can let some crabgrass through in the holes. If spring is the only option, aerate first and apply the preventer straight after, rather than the other way round.

Why is my lawn still hard after one aeration?

One pass loosens a few percent of the surface. Heavily compacted clay improves over several years of annual aeration with compost topdressing, not in one visit. Ask for a double pass in two directions on a badly compacted lawn, which usually adds 30 to 50% to the price and roughly doubles the effect.