How to Keep Grass from Growing Under the Fence

Yard maintenance is an ongoing effort, especially in the summertime. Rather than constantly trying to fight the grass that grows under the fence, you can make some changes so that it doesn’t grow in the first place. Here’s how to keep grass from growing under the fence so you have one less chore this summer.

I have a large yard, so I know better than anyone how much work maintaining the fence can be. Some of these strategies are best done when you first build your fence, but you should be able to apply them to an existing fence too.

Keeping the grass trim under the fence makes your yard look a lot cleaner, especially if you live in a community where curb appeal matters or are planning to sell your home.

How to Keep Grass from Growing Under the Fence

But grass under the fence is hard to trim, even if you have a whipper snipper. Here’s some great, budget-friendly ways to prevent grass from growing under the fence. 

Chemical Spray (Eg. RoundUp/Glyphosate)

I’m just going to rip this one off like a band aid since it’s probably the simplest and most effective way to keep grass from growing under the fence. It’s also the most controversial, since more people are moving away from chemical solutions in their yard. 

There are home spray bottles you can use or professional services that spray along the fenceline. It can stay active for up to six months, meaning you can spray in the spring and enjoy a grass-free fence line all summer long.

Disadvantages

First of all, chemicals need some time to dissipate in order to keep your kids and pets safe in the yard. That means you should spray them if you can’t wait at least 24 hours before using the area.

Second, chemicals should be avoided around other plants you want to grow, including trees, flowers, and shrubs. You also want to keep weed killers away from the garden. 

Third, the chemicals in herbicides can deteriorate your fence materials, especially metal fences. Make sure you’re spraying the ground and not the fence.

Finally, some jurisdictions don’t allow certain products to be used in residential lawns so check with your local bylaws.

Natural Options

There are other brands out there that work similarly to Glyphosate available commercially. Some are made of ingredients like citric acid, which is a natural herbicide that has minimal environmental effects. Citric acid lasts up to a year, but otherwise will dissipate over time.

Certain “natural” weed killers are made of common household products and carry their own risk.

Salt the Earth

Ever wonder where this expression comes from? Salt is a natural herbicide, and can be a great way to kill grass in a way that isn’t harmful to the environment or dangerous for the groundwater.

Mix water and salt (table or epsom) in a 3:1 ratio. The salt will dissolve best in warm water. You can then add it into a spray bottle (use one with a “jet” style spray), a squirt bottle (like for condiments), or in a specially designed chemical spray system.

You can also add a few drops of vinegar and/or Dawn dish soap to the solution for an even stronger effect. Alternatively, swap the water with white vinegar for an even stronger spray.

It will start working within 24 hours but can take up to 10 days for the salt to kill the grass and weeds under your fence. Expect results to last 3-4 weeks before you start seeing regrowth, but with reapplication you should get good results over time.

This solution will kill everything it comes in contact with, so make sure you avoid spraying on any plants or grass you want to keep.

A Note About Salt – Use Caution

Please keep in mind that the salt doesn’t break down over time, and is only removed by being leached out by water. Once you apply salt it can be years, or even decades, before anything can grow there naturally. 

It’s also theoretically possible for the salt to be washed into the surrounding area where you might want grass to grow. For that reason I highly recommend doing some edging at minimum around any area you plan to use salt as a herbicide.

Finally, salt can break down concrete and damage certain fence materials. 

Bury the Fence

Can’t grow grass under the fence if it’s under the ground! If you have a dog that likes to escape or dig this could be a win-win. Make sure your fence materials are treated, and be aware that wood is more prone to rot when buried or touching the ground.

If your fence is already in place you can also add additional dirt around the fence and build it up a bit, but it won’t be as nice as burying the fence during construction.

A buried fence is also good at preventing stray pets or other critters from entering your yard or garden.

Fence Footers

If you want a better long term solution, or your fence is already up, footers are another option. They’re usually made of galvanised steel mesh, like chicken wire, in the shape of an L. 

The top part is laid out next to the fence or right under it, and the bottom part of the L gets buried underground. Not only can this stop weeds, but also pets and critters from getting in or out too.

Add a Barrier

There’s two kinds of fence barriers you can add to stop grass from growing under it.

The first is a strip that fits on the bottom of the fence and reaches down to the ground. For chain link fences, it’s usually made from plastic and can be installed with relative ease. On a wood fence, this is often called a rotboard or kickboard. It can be installed horizontally after the fence is up and changed out when it wears.

The second type of barrier is one underneath the ground that gets buried right under the bottom of the fence. It needs to be placed shallow enough that grass can’t take root on top, but also deep enough that you won’t see it. 

You can use almost any material for a buried barrier as long as it’s the right size, durable, and will not allow the grass to penetrate. Popular options are old bricks, asphalt shingles, strips of carpet, and plastic.

Dig Out the Grass, Trench, and Edge

Ever wonder why you see so much mulch in nice neighbourhoods? It not only looks cleaner and more expensive, it also keeps grass from growing in places you don’t want it.

First of all, dig out a trench under the fence. You need to make it deep enough to get the grass out at the roots or else it could grow back, even if you add mulch later.

There’s a few options with this.

Small Trench

The first is to just dig under the fence. You can opt out of filling it with anything, most of the grass will not grow back as long as you’ve completely removed it. 

Filled Trench

Due to erosion and other factors, plus the aesthetic, it’s a good idea to fill the hole with something. If you plan to fill it with something like mulch, gravel, or lava rocks then it’s a good idea to dig the trench out wider than just under the fence. That will also save you having to cut the grass along the fence too.

Once the ground is dug out, lay a landscape cloth down. This will keep all your materials from sinking deeper into the dirt and allow water to drain. 

Then add in your material of choice to fill up the trench. 

Edging

It’s also a good idea to properly edge the area. Rubber landscaping edging is a great option, and it will help keep your rocks or mulch inside their trench. 

Maintaining an edge (by digging a small trench down into the grass) will also help keep clumping grass from spreading where you don’t want it.

Hardscape

Like trenching or underground barriers, hardscape solutions use decorative elements to create a barrier and stop grass from growing. Paving stones and bricks are great options.

You’ll have to dig a trench under the fence to the width of your stones and about 1.5 inches deeper. Then add in landscaping fabric and cover it with 2 inches of sand.

Lay out your stones and hammer them in with a mallet so they can’t move; they should be about ½” above the ground.

Concrete

There’s a few ways to do this. If you’re also trying to block off escapes for dogs, it might be best to just pour concrete along the base of your fence. You’ll get no grass or weeds, and nothing can get in or out.

For a nicer look, you can also pour a small amount of concrete along the bottom of your fence. Some people do this freehand, but it will look much better if you dig out a trench to the size and thickness you want to concrete pad, then pour it carefully.

Smother The Grass

This will result in some dead grass that you may still need to remove, but it’s a viable option if you don’t have time for yard maintenance and need it gone. You can use almost any old materials that are laying around, making this an easy DIY option.

Cut down vinyl flooring, shingles, wood pieces, or anything that is heavy and thick enough to smother the grass but small enough to fit under the fence. Just remember that your grass will die to the width of the material so don’t use anything too wide.

Once the grass has died, clean up the area.

Garden Beds

Some people choose to turn their fence line into flower beds. This is a win-win; you won’t have to maintain the grass, and you can use what might have been dead space for growing flowers. 

Not only do many perennials grow well against a fence (look for ones that like shade), but you can also grow vegetables in these beds too. Zucchini, cucumber, peas, squash, and even tomatoes depending on sunlight are great options.

Just make sure you have adequately removed all grass roots when digging out the beds and add some new topsoil.

Hide or Choke Out the Grass

This may not be everyone’s favourite option, but sometimes if you can’t beat ‘em it’s not so bad to join ‘em. Especially when it comes to nature! 

Rather than worrying about the grass under the fence, hide it with shrubs or hedges. You can also plan your yard so that structures and decorative items hide problem areas. 

Another option is to plant ornamental grasses along the fenceline. These often choke out the ordinary grass, leaving you with something that looks decorative and intentional rather than unkempt. Just be careful that it doesn’t spread throughout the yard (unless you want it to.) 

Finally trees, especially spruces, can also have a choking effect because they suck ground water up around them and litter the area with pine needles. At least in my yard, nothing grows around them so when planted along the fence line they have become a natural grass killer.

While these ideas won’t work for the manicured lawn look, it’s a great option for someone who likes that overgrown “English garden” vibe or who lives in the country.

Alternative Ground Covering

Grass-alternatives that cover the ground like clovers, moss, creeping thyme, and other creeping vines or plants can be used as alternatives to grass to cover the ground. Most of the time they look nicer than grass, and won’t grow up in the same ways.

If you really want to win the battle with grass, you could also consider installing artificial turf either along the fence line and under it, or over the whole lawn.

How to Keep Grass from Growing Under the Fence – Final Thoughts

Some of these options will solve the problem quickly, others are better for long term solutions or overall landscaping. It all depends on what your goals are for your yard, your lifestyle, and your budget.

Keep in mind that with landscaping, you’ll always want to remove the grass down to the root and edge the area properly to keep it looking tidy. 

Even if it seems like work upfront, putting the effort in to keep grass from growing under the fence really pays off in time saved maintaining your yard.