Replacing Grass With a Garden Bed

Close up of tomatoes, growing on vines
Caiaimage/Martin Barraud / Getty Images

Many homeowners, not just devoted gardeners, are discovering the benefits of replacing lawn grass with planting areas for vegetable gardens, flower garden beds, or mixed shrub/flower islands. Integrating planting areas within the lawn makes for a landscape that is more aesthetically pleasing, and it can also provide space to grow healthful food or practice a rewarding flower-gardening hobby. Then there is the simple benefit of reducing the lawn-care chores. The less turf-grass you have in your landscape, the less mowing/weeding/fertilizing you'll need to do. In fact, one of the fastest growing trends in residential landscaping is replacing grass lawns with non-grass substitutes.

To add planting areas to your landscape, though, you need to deal with the turf grass that currently makes up your lawn. Turfgrass species are bred to be tenacious and to spread, and unless you find a way to remove that grass, it is sure to pop up in your newly established planting bed, where it will lead to never-ending combat to remove it.

There are several ways to remove or kill the grass to make room for garden planting areas. Some of these methods are fairly simple but require patience and time. Others are very quick, but they require a strong back and plenty of energy. No matter which method you use, you'll end up with less lawn and more gardening space.

Whichever method you use, a good first step is to cut the grass as low as possible in the area you are removing. It will speed things up and make the process easier.

Sod Busting

Let's get the most brutal method out of the way first: removing the sod by hand (and the back and the legs). Cutting the turfgrass area into pieces and prying out and discarding the pieces of sod is arguably the very best way to remove the grass and prepare the area for a garden bed. Removed entirely, the grass won't grow up through your new garden, although you do need to take pains to remove it all since any remaining grass roots will quickly create new plants.

Aside from the sheer physical effort it takes, this method has a drawback of removing some of the soil from the planned garden area. Even if you shake off as much dirt as possible, some valuable soil will be removed from your garden area. If the soil in your yard is sparse or weak, you likely will need to add amendments in order to establish a good planting area in the space where you have removed the sod.

How to Do It

Use a garden hose, string, or stakes to outline the garden area. Begin with a thorough watering to soften the planned garden area. Use either a half-moon edger or a sharp space to cut the sod at the edges of your new planting bed. Cut the area into a series of narrow strips using the spade.

Once you've got the edges and strips outlined, then it's time to dig. There are many tools for removing sod, but a good sharp spade or shovel works just fine. It's a good idea to try to remove as little soil as possible, so keep your spade at a low angle in order to get the roots while leaving most of the soil behind. Toss the sod into a wheelbarrow or other container as you go; you can compost it or use it to patch other areas of your lawn

Pros: Once it's done, it's done. You have a bed, ready to plant. Requires very little planning, so if you're a spur-of-the-moment type, this method will work for you.

Cons: It is a lot of physical work. On the other hand, you won't need to go to the gym on the day you made your garden bed. If you have back or joint issues, you may want to leave this job to someone else.

Solarize the Grass

This is a method that takes a bit of patience and planning, but if you had a lot of weed problems in your existing lawn, it may be the way to go. Solarizing is a method of killing grass (or other plants) by focusing the sun's heat through a sheet of plastic.

How to Do It

Solarization requires that you cover the area of your planned garden with one or two layers of thick plastic and leave it in place for 6 to 12 weeks until the heat of the sun bakes and kills all living plants beneath the plastic. Sealing the edges of the plastic will help keep the heat in and speed up the process. If you have particularly tenacious weeds (such as bindweed), a longer solarization period (up to 6 months) will kill those weeds along with the turfgrass.

Once the grass is dead, pull up the plastic, amend the soil, and garden away. There is no need to remove the dead grass, as it will simply decompose and add nutrients to the garden soil.

Pros: Solarization definitely kills the lawn grasses and any nasty weeds you were contending with. There is very little physical work with this method.

Cons: Patience is required, since this process can take anywhere from 6 weeks to 6 months, depending on the amount of sun the area gets and how bad the weeds are.

Smother the Lawn

This is another very easy ways to start a new bed. It involves denying the grass of air until it dies naturally. Like most easy methods, though, it requires a fair amount of time—as much as 6 months. Almost any material can be used to smother the grass—old newspaper, chunks of carpeting, and pieces of cardboard are common options.

How to Do It

Once you've figured out the size and shape of your bed, gather your materials to smother the lawn and simply lay them over the grass. This is best done in the late summer or fall so the grass can die over the winter. The following spring, you can amend the soil and begin planting. Here, too, there is no reason to remove the dead grass—once it is dead, it will decay and become a source of nutrients for the garden area.

Pros: Very little work required. Does a good job of killing the grass.

Cons: As the grass is being smothered, the method can look shabby and unattractive in the landscape. A good solution is to cover your smothering material with fall leaves or bark mulch. You can pull the mulch back when you're ready to plant.

Lasagna Gardening

A lasagna garden, built in the fall, will provide you with a ready-to-plant garden bed in the spring. This method serves to smother the underlying grass even as it creates a garden bed with good, nutritious soil. As the name suggests, lasagna gardening uses a technique of placing layers organic materials over the garden area, which creates a perfect growing medium as the layers decompose.

How to Do It

After outlining the garden area, first, apply a thick layer of cardboard or newspaper over the grass. This will constitute the smothering layer that serves to kill the turf. Over this, apply several layers of organic materials over the cardboard. Common organic materials you can use include:

  • Prepared compost
  • Grass clippings
  • Leaves
  • Fruit and vegetable scraps
  • Coffee grounds
  • Tea leaves and tea bags
  • Decomposed manure
  • Seaweed
  • Shredded newspaper or junk mail
  • Pine needles
  • Spent blooms and trimmings from the garden
  • Pros: This is a very easy method. The resulting garden soil will be a perfect garden growing medium, fluffy and full of organic matter.
  • Cons: The method requires patience. You'll have to plan ahead so you can build the bed at least 6 months in advance of when you want to plant it. If food scraps are used, they may attract insect and animal pests. Organic materials decomposing in the open sometimes are smelly.

Build Raised Beds

Raised beds are great if you know your soil is not great (high clay or extremely sandy, acidic pH, etc.) The method involves simply building a raised structure with wood, stone, or another material, then filling it with good quality garden soil, compost, and composted manure. Instant garden!

How To Do It

After outlining the garden area, build a structure 8 inches or more in height around the perimeter of the garden.If the bed is 8 inches or deeper, you don't even need to really worry about smothering the grass below, since it will die all on its own. However, if you'd like to, simply lay down a few layers of newspaper before filling the bed.

Fill the raised bed with a mixture of good black garden soil purchased from a landscape supplier, thoroughly mixed with organic amendments, such as compost or peat moss. Then garden away.

Pros: This is an easy, quick method that allows you to garden immediately. Since you are creating your own soil, you can create a garden with ideal growing properties.

Cons: There is an additional cost associated with buying the materials, as well as the garden soil and amendments.

Apply Herbicides

It's not for everyone, but the grass in your planned garden area can be killed off with the right kind of herbicide. The herbicides normally used for lawn weeds do not kill blade-leafed plants like grasses, so you will need a broad-spectrum vegetation killer. And many vegetation killers will leave residual traces in the soil, so it is best to use a glyphosate-based herbicide (RoundUp, etc.), which becomes inactive as soon as it contacts certain soil enzymes. Within a few days of application, glyphosate is undetectable in the soil. It is this property that contributes to glyphosate's reputation as a relatively safe chemical, though it does not mean that it is harmless to humans.

Caution: Glyphosate is a controversial herbicide. Once thought to be fairly innocuous and safe, recent research suggests that it may have some of the same cancer-causing properties of other, more notorious lawn chemicals. While most university horticulturalists do not believe glyphosate is dangerous, homeowners devoted to organic gardening practices will want to exercise other methods of killing grass.

How to Do It

Apply a glyphosate-based broad-spectrum herbicide to the planned garden area with a sprayer on a windless day. Make sure to carefully confine the spray to the area of grass you want to kill since this herbicide will kill whatever plant material it touches. Once the grass area has turned brown and brittle (it may take a week or so), it is dead and ready for you to add amendments to the area and dig them in. There is no need to remove the dead grass—just dig it in along with whatever amendments and extra soil you have added. The dead grass will naturally decompose and add nutrients to the soil.

Pros: Glyphosate herbicide is a very quick and thorough way to kill grass.

Cons: All herbicides are controversial, and their use is strongly criticized by organic gardeners. Glyphosate is a safer chemical that some other herbicides, but it is still a chemical and must be used with great caution, if at all.