Lawn shrinking? Three ways to get rid of grass before planting anything else

The perfect green lawn – once revered as the hallmark of a responsible homeowner – seems to have taken a turnaround.

At least in some circles, a large, weed-free lawn is now demonized as a “biological wasteland” that could/should be used in a more productive or environmentally friendly way.

Increasing heat and local drought in summer are also putting a strain on our traditional cool-season turf grasses, leading to mid-season browning or even plant death.

Whether it’s converting the area to vegetables, creating a pollinator-friendly meadow, or creating a rain garden to protect streams from flooding, the trend is toward reducing lawn size.

For those who dare to take the plunge, the question arises as to how exactly the shrinking should be done.

No method is particularly easy, but you have at least three options for killing your lawn. Late summer to early fall is the best time to do them all.

The traditional kill-and-till method

This is the quickest way to convert a lawn into a garden, but it is also hard work.

The first step is to kill and/or remove the grass.

One option is to spray the soil with an omnivorous herbicide such as glyphosate or glufosinate if you are a chemical gardener, or with vinegar (acetic acid), ammonium soaps made from fatty acids, or various vegetable oil sprays if you are an organic gardener.

Once the grass has died back (usually within a week or two), the bed can be tilled, planted and mulched. You can also work compost into the bed at this point if your soil is poor.

Just check the label of the herbicide you are using to find out how long you need to wait before replanting.

A non-chemical alternative is to start plowing straight away. Although a large enough tiller can dig up living turf, the downside is that it leaves behind clumps of grass that can take root again… unless you have the energy to remove the clumps and compost them.

A second, non-chemical alternative is to remove the lawn with hand tools – or, for larger areas, rent a petrol-powered sod cutter. You can then dig up or till the bare soil, work in compost and replant.

The dug up turf pieces can be turned over (root side up) on the prepared bed and mulched to take advantage of the decaying organic matter. Or the pieces can be composted or used to patch bare turf elsewhere (free sod).

If you are a planner, you can kill the turf by covering it with black plastic or horticultural fleece for at least several weeks. Then the dead turf can be planted (if the soil is good) or dug up, amended with compost and replanted (if the soil is poor).

Insider tip: Whether you spray or plough, dig a 15 cm wide strip around your new bed to separate the “holder grass” from the future garden.

Insider tip 2: Before digging, find out about the lines or call Pennsylvania One-Call at 811 to have the lines marked. Some internet and cable lines are only a few inches deep.

Layered composting or the “lasagne” method

This method has gained attention recently because it avoids the entire process of digging, plowing and using chemicals.

“Instead of removing the existing lawn or weeds, surface composting creates the new bed on top of them,” writes Dr. Debra C. Burrows, former Clinton County Master Gardener Coordinator, in a post on the Penn State Extension website.

The first step, she says, is to cut the grass short. Leave the clippings.

Step two is to cover the area with overlapping pieces of corrugated cardboard (flat shipping boxes work well) or at least five sheets of dampened newspaper.

In the third step, this layer is covered with a five centimeter thick layer of nitrogen-rich ingredients such as compost, well-rotted manure, grass clippings, dead garden plants or vegetable waste.

In the fourth step, this layer is covered with a five centimeter thick, carbon-rich layer of ingredients such as wood chips, dry leaves, sawdust, shredded paper or pine needles.

“Repeat this with alternating layers of nitrogen and carbon until you reach a height of 18 to 36 inches,” says Burrows. “That may sound a bit high, but remember that the materials will shrink as they decompose. Cover the entire bed with a layer of carbon, such as bark or mulch, as a top layer and moisten lightly with a hose. The bed is ready for planting vegetables or annuals when the materials have decomposed to the point where individual components are no longer discernible.”

If you stick with perennials, Burrows says you’ll need less material. After laying down the cardboard or newspaper layer, she recommends a two- to three-inch layer of mulching material, such as leaves, grass clippings or shredded hardwood mulch.

“Once the layers are in place, all the gardener has to do is wait,” she says. “The process can take up to six months or more, so fall is an ideal time to start. Decomposition will occur over the winter and the new garden bed will be ready for planting the following spring.”

Penn State Extension’s York County Master Gardeners recommend spreading four to six inches of mulching material such as dead leaves, grass clippings, wood chips, bark mulch and/or pine needles over the cardboard or newspaper. (They recommend 10 layers of newspaper.)

The York County MGs posted a five-minute video of the incident online.

Suffocation by wood chips

This is the simplest method, but the challenge is sourcing the wood chips and then distributing what could be a huge amount of them.

Wood chips (sometimes called “tree trimming chips”) are what is left over when a tree trimming company chips up branches and trunks after trimming or cutting down a tree.

They have never really caught on because they look a bit “rough” to some people and there are rumors that they “remove nitrogen from the soil as they decompose” and may introduce pests or plant diseases to properties.

Although none of these threats have been confirmed by research, the trick is to get the chips in the first place.

One option is to contact local tree service companies and ask if they will drop off a load the next time they are in your area. It may be free.

Another online service called Chip Drop connects residents looking for wood chips with tree service companies looking for places to dispose of them. This service is also free, unless you want to increase your chances by making a donation.

The U.S. Geological Service Bee Lab described the wood chipping process in a fact sheet at the 2024 Philadelphia Flower Show.

The lab says you shouldn’t put anything under the wood chips… you should just spread them 20 centimeters high on the grass, which doesn’t even need to be mowed.

“You can plant immediately, but if you have time, lay the wood chips well in advance of your planting schedule so that the grass and weeds underneath have time to decompose,” advises the leaflet. “This makes planting a little easier.”

The roots of the plants should at least be touching the soil beneath them, not completely “floating” in the wood chips. Mulch can be pushed around the plants as they grow, and more mulch can be added in subsequent years to suppress weeds.

Dr. Linda Chalker-Scott, a horticulturist at Washington State University and author of The Informed Gardener, is also an advocate of using wood chips for establishing new garden beds.

She generally advises against composting with cardboard, newspapers and foil, as “these hinder the movement of air and water”.

Their advice consists of a four-step process:

1. Mow the lawn as close to the ground as possible.
2. Cover it with a layer of arborist wood chips – at least 8 inches thick and up to 12 or 18 inches. “They settle quickly, so you need to lay down enough of them to maintain a depth of 6 to 8 inches after a few weeks,” says Chalker-Scott.
3. Wait. Lawn decomposition depends on temperature and water. Warm, moist conditions are ideal. After two to four weeks, pull back the mulch and check what’s underneath.
4. When it’s easy enough to dig under, plant. “Be sure to push the mulch aside and plant in the ground,” says Chalker-Scott. “Put the mulch back on to cover the disturbed soil and keep the weeds at bay.”

Chalker-Scott says that while at least 8 inches of wood chips will provide a lot of material to spread, it is lighter and easier than the layering of multiple materials required in layered composting.

• Read George’s column on four ideas for replanting when the grass is gone