Can You Put A Planter Box On Grass? (With Gardeners Inputs)

You’re excited.

You bought a planter box and can’t wait to grow plants in it.

But there is grass growing in the area where you want to place the planter box. Will this be a problem?

You can put a planter box on grass, but you should take the precautions to prevent the grass from growing into the planter. You can pull out the grass or kill the grass before placing the planter box. You could use a deep planter box or use a raised planter box.

In this post, I’ll help you understand how you can put the planter box on grass. I’ll also give you information on how to get rid of the grass if you want to.

Let’s take a look.

How to put a planter box on grass

You can either remove the grass or keep it before putting the planter box on top of it. Each of these methods has its pros and cons.

1. Remove or kill the grass

Pull out the grass

The simplest way to remove grass is to pull it out of the ground. It will be hard to use your hands if the grass has deep roots. It’s best to use a shovel to dig out the grass along with the roots.

You can first mark the required area with stakes so you only need to dig up a certain space required for the planter box.

Put the stakes on all four corners of the area where you’re going to put the planter box. Wrap a string around the four stakes so the borders are clear on where you need to dig.

Pull up what you can and then lay down cardboard. It will last a little while. I hate Bermuda grass!!! – Jamie

Now use a shovel to dig out the dirt and place it either in a pile or a wheelbarrow. You can add the pulled out grass to the compost pile. Just make sure that you place them inverted so the roots are sticking out of the pile. This helps prevent the grass from growing in the compost pile.

You can put the dirt back into the dug up area after you’ve removed all the grass from it. Smooth out the surface before you can put the planter box on it.

I asked fellow gardeners what they do to kill the grass they don’t want in their garden. 59.6% gardeners agreed that the best solution is to smother the grass under newspaper or cardboard.

Kill the grass

If you don’t want to spend the effort pulling or digging the grass out of the soil, you can use methods to kill the grass.

I don’t recommend using chemical options that may be found in plenty. Because they damage the soil and can seep into the water, harming wildlife.

The simplest option is to use boiling water on the grass to kill it. Be careful when moving the boiling water to the location so you don’t spill it on yourself.

The other option is to use salt water that dehydrates the grass and kill it. The problem is the salt will remain in the soil for a while until it leaches out with watering or the rains.

Do remember that these options will kill the grass and any other plant that is growing in that area.

Solarize the grass

If you have the time of 4-8 weeks during spring/summer, you can kill the grass by heating it up.

Place a plastic sheet on top of the grass. Any color sheet will do, but it probably is good to use a black sheet that can absorb more heat.

Place heavy stones at the four corners of the plastic sheet so it does not fly off. Leave this sheet on the grass for 4 to 8 weeks and the grass should die because of the heat.

Solarizing will kill a lot of the microbes and fungi and goodness in there. Cardboard won’t. – Mikaela

Smother the grass

Another easy option is to smother the grass so that it cannot grow and dies out. You don’t need to spend your energy in pulling the grass out.

Just trim the grass and put a layer of certain materials on top so that the grass suffocates and dies out. You can choose from several materials such as newspaper, cardboard, plastic, and landscape fabric.

Once you have placed the layer of smothering material, you can place the planter box on top of this. The grass will have no means of getting sunlight and will die.

I have 3 female dogs, they did a great job at killing my grass. But in all seriousness, smothering the grass to keep sunlight off them is the best way. – Allan

2. Put a layer of materials on top of the grass

Once you’re done either removing or killing the grass, it’s time to add a layer of materials on the area. You can place the planter box on top of this material.

Adding such material will ensure any remaining grass will get smothered. It can also help decompose and provide organic matter to the soil underneath.

Here are some options you can choose from.

Newspaper

The simplest option is to spread a couple of layers of newspaper on top of the grass. This will help smother the grass and gradually decompose to enrich the soil.

Cardboard

Cardboard is a similar option to newspaper that you can put on top of the grass. It will decompose a lot slower than newspaper.

Gravel

You could put gravel on top of the grass and then place the planter box on top of it. I don’t prefer this option, as the gravel can interfere with the drainage of the planter box.

Landscape fabric

Landscape fabric is a good option to place on top of the grass. It will help smother the grass but allow proper drainage of the excess water from the drainage holes of the planter box.

Should a planter box be placed above the ground?

 If you don’t want to pull or kill the grass in the area, you can consider raising the planter box above the ground. This helps prevent the grass from reaching the planter box and the potting soil in it.

You can get a planter box that already has legs to stand on. Or you can make the planter box stand on something stable, such as stones, bricks, wood pallets, or concrete blocks.

Make sure that the drainage holes of the planter box are clear when you place it on a stand. You want the materials like stones or bricks only to hold the edges or corners of the planter box. The bottom of the planter box should remain above the ground, but without touching the stones or bricks.

Can you put a planter box on concrete?

You should not put a planter box directly on top of concrete as it can block the drainage holes at the bottom of the planter box.

 It’s much better to place the planter box on a stand made from concrete blocks, wood, stones, or bricks. This stand will help keep the drainage holes clear above the concrete.