Can You Put a Raised Garden Bed on Grass? (Do This First)


Many gardeners wonder if you can put a raised garden bed on grass, and if so, what you need to do first.  It can be a lot of work to remove grass before planting a raised garden bed, but do you need to do it?

So, can you put a raised garden bed on grass?  Yes, you can put a raised garden bed on grass.  However, you should take steps to prevent the grass from growing up into the raised bed.  One way to do this is to smother the grass with cardboard or plastic and then pile up the soil in your raised bed to a depth of at least 12 inches (30 centimeters).

Of course, you can also remove the grass before building your raised garden bed.  This will prevent the grass from growing up into the raised bed.

Let’s take a closer look at how to remove grass before planting a raised bed.  We’ll also look at ways you can build your raised garden bed on grass, some of which do not require chemicals, digging, or heavy equipment.

Can You Put a Raised Garden Bed on Grass?

Yes, you can put a raised garden bed on grass.  If the soil is piled deep enough, it will smother the grass under a raised bed.

grass
If the soil in a raised bed is deep enough, then grass will have trouble growing up through it.

However, if the soil in your raised garden bed is shallow, then it might not be able to kill the grass.  In that case, the grass can grow up through the soil and compete with your plants for water and nutrients.

To prevent this from happening, you have two options:

  • Remove the grass before building your raised bed
  • Kill the grass in place before building your raised bed

Let’s start off with some ways you can remove the grass before building a raised garden bed.

How to Remove Grass for a Raised Garden Bed

Removing the grass before you build a raised garden bed can be a lot of work, whether you do it with a shovel or power equipment.  However, removing the grass ensures that you won’t have any grass growing up into your raised garden bed once it is built.

Just remember to call the utilities in your area to check for underground lines (gas, water, etc.) before you do any digging.  This advice applies even if you think the digging will be shallow!

Dig out the Grass

One of the simplest ways to remove grass is to just dig it out.  At a minimum, you will need a shovel, 4 stakes, and some rope or twine for this job.  A pitchfork and wheelbarrow will also be helpful.

shovel
Time get digging. Don’t do too much at once, or you will be sore!

First, mark off the area where you want to remove the grass.  This area will need to be at least as large as the raised bed itself.

To mark off the area, drive a stake into the ground at each of the four corners of the spot you want to clear.  Then, tie a rope or string between the stakes to mark the edges.

These ropes will guide your digging and prevent uneven edges.  Use the shovel to dig as deep as the roots go, and pull up chunks of grass as you go.

You will need to do this for the entire area you marked off.  Take my advice: for a large area, do this project over multiple days, especially if you are not used to digging!

Otherwise, you will be sore (very much so).  Once the digging is done, you can use the pitchfork to remove soil from the roots of the grass.

Put the soil back where it was.  That way, you won’t need as much extra soil to fill the area back in.

Toss the grass and roots into your wheelbarrow and move them to your compost pile.  Leave the chunks of grass on top of the compost pile, with the roots facing up.  That way, the grass cannot establish itself on your compost pile.

Use as much extra soil as necessary to fill in the area you dug up.  Make it level with the surrounding ground.  Now you are ready to build your raised bed!

Use Power Equipment

If you want to get rid of grass without digging, then using power equipment is an option.  A turf cutter or a tiller can help you to remove grass to prepare for a raised garden bed.

Sod Cutter (Turf Cutter)

You can either buy or rent a sod cutter (turf cutter) to help remove grass.  A sod cutter is a machine that removes a strip of grass with the roots and soil still attached.

sod
A sod cutter (turf cutter) removes strips of grass with the roots and some soil still attached. You can replant these strips elsewhere in the yard!

The best part about using a sod cutter is that you can reuse the grass after you remove it.  After cutting out a strip of sod (grass, roots, and soil), you can move the strip somewhere else in the yard where you want grass to grow.

If this sounds like the right method for you, then you can rent a sod cutter at many Home Depot locations.

Tiller (Rototiller)

A tiller (or rototiller) is another piece of power equipment you can use to remove grass.  There are both electric and gas powered tillers.

rototiller
A large rototiller will get the job done faster when removing grass, but it will be much heavier than a small one.

Remember that a tiller will tear up the grass and separate it from the roots.  As a result, you will not be able to replant the grass elsewhere in the yard.

However, if you just want to compost the grass, then a tiller is a good option to save yourself from digging.  A rototiller is helpful if you need to break new ground when starting a garden for the first time.  You can learn more about rototillers in my article here.

After you use the tiller to tear up the grass and break up the ground, you can put the grass in your compost pile.  That way, you can reuse the organic material and nutrients for next year’s garden.

You can rent small or large rototillers at Home Depot. I go into more detail about the weight of rototillers in this article.

How to Kill Grass (Without Chemicals)

If you would rather kill the grass before building your raised garden bed, you do have some options.  The methods I have listed below will kill the grass without any digging, chemicals, or heavy equipment.

Organic Weed Killer

If you do not want to use herbicides to kill grass in your garden, I don’t blame you.  There are some nasty chemicals in those products, and they can kill the plants you do want to grow (like the vegetables or flowers in your raised bed!)

Luckily, there are some organic weed killers you can use to avoid harsh chemicals.  The Utah State University Extension has many home remedies for weed and grass control listed in this article.

One method they mention is to apply a solution of salt water to the grass.  The upside is that this salty solution will kill the grass.  The downside is that other plants nearby (or ones in your raised garden bed) might not like the salty soil either!

You can also try spraying the grass with a solution of vinegar.  The acidity might kill the grass, but it could also hurt nearby plants, so be careful when using this method.

Another method is to use boiling water to kill the grass.  Just be very careful when moving boiling water from the kitchen to the garden.

boiling water in kettle
Boiling water will kill grass. Just be careful when moving it from the kitchen to the garden.

Remember that if you splash boiling water on nearby plants, it will kill them too.  Boiling water does not discriminate!

Cover with Plastic (Solarization)

If you have some time to spare, you can use a combination of solar energy and the greenhouse effect to kill grass.  This method requires some time and patience, but it doesn’t take much work on your part!

First, use a plastic sheet to cover the area where you want to kill the grass.  A dark plastic tarp will work.  However, clear plastic will work better, according to the Cooperative Extension.

plastic tarp
A plastic tarp will work for killing grass with the heat of the sun. Clear plastic works best, though.

Use stones or bricks to weigh down the corners and edges of the plastic.  This will keep the plastic from blowing away or moving out of place in the wind.

After the plastic is securely in place, leave it for 4 to 8 weeks.  The sun will heat up the air and soil underneath the plastic.

The plastic will keep the heat from escaping (using the greenhouse effect to your advantage!).  The sun will continue to heat up the air and soil under the plastic over time.  Eventually, the grass will die from the heat.

Note: the soil needs to be covered during the warm part of the season.  Otherwise, the soil will not heat up enough, and the grass will not die.

This method will take a couple of months, and the sun needs to be strong.  If it is already spring and you need to kill the grass this year, you should use another method.

Smother with Cardboard or Newspaper

First, cut the grass as short as possible.  To do this, adjust your mower so that the blades are as low as possible.  Just watch out for rocks while you are mowing with the blade set low!

Then, cover the grass you want to kill with a thick layer of cardboard or newspaper.  A thicker layer is more likely to kill the grass and keep it from growing back.  However, a thick layer will also take longer to decompose.

flat cardboard boxes
A thick layer of cardboard will smother grass and prevent it from growing up into your raised bed.

After this layer of cardboard or newspaper is in place, build your raised garden bed over it.  When the cardboard or newspaper decomposes, along with the grass, it will add nutrients and organic material to the soil.

You can learn more about the cardboard and newspaper method of killing grass in this article from the University of Maryland Extension.

Use a Raised Garden Bed Liner

If you use the right liner, you might be able to prevent grass from growing up into your raised garden bed.

A liner made of plastic or landscape fabric will prevent grass from growing up into your raised garden bed.  However, there are some downsides to using raised garden bed liners.

For example, plastic raised bed liners will reduce drainage. You can learn more about how to improve drainage in your raised garden bed in my article here.

You will have to weigh the pros and cons of liners for your specific situation.  You can learn more about the pros and cons of raised garden bed liners, along with what materials are available, in my article here.

Pile Up the Soil High

Finally, if you pile up the soil high enough in your raised garden bed, you will not have to worry about grass growing up through it.

If the soil is piled up to a height of 12 inches (30 centimeters) or more, then grass does not have much chance of breaking through.

Conclusion

Now you know what to look out for if you decide to build a raised garden bed on grass.  You also have some ideas about how to kill or remove the grass before building your raised garden bed.

I hope you found this article helpful – if so, please share it with someone who will find the information useful.

Yes, you can put a raised garden bed on grass. However, you should take steps to prevent the grass from growing up into the raised bed. One way to do this is to smother the grass with cardboard or plastic and then pile up the soil in your raised bed to a depth of at least 12 inches (30 centimeters).

jonathon.david.madore

Hi, I'm Jon. Let's solve your gardening problems, spend more time growing, and get the best harvest every year!

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