Homesteading, Gardening, and Off-Grid Living

Should I Use Landscape Fabric Under Mulch? Pros and Cons

By: Zac Friedman

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Some gardeners use landscape fabric under their mulch to prevent weed growth in their gardens. Generally, this is a bad idea. Landscape fabric may keep weeds down for a couple of seasons but it doesn’t last forever. Eventually, weeds will start growing on top of the fabric or through it. Landscape fabric is also bad for your soil, it’s unattractive, it’s difficult to remove, and it’s bad for the environment. It can also make it more difficult for plants to grow. Most gardeners are better off without it. That said, there are a couple of cases where it can be beneficial, such as under rock mulch. This guide will help you determine whether or not to use landscape fabric under your mulch. 

Should I Use Landscape Fabric Under Mulch?

Why People Use Landscape Fabric

The main reason people use landscape fabric is to block weeds. Landscape fabric prevents weed seeds that are already in the soil from germinating and growing by blocking the sunlight. It also prevents seeds that are blown in or dropped by birds from reaching the soil. Blocking weeds is the main use of landscape fabric. 

There are different types of landscape fabric available. Most are made from a non-woven textile. They are basically just big black plastic sheets. The sheets are usually perforated so water and air can pass through into the soil. 

The fabric is placed over sections of the garden with lots of weeds. Mulch is placed on top to hold the landscape fabric in place, help block sunlight, and improve the aesthetics of the garden. The fabric smothers the weeds.

You can buy landscape fabric at any garden center. It’s sometimes referred to as weed fabric or landscape cloth. 

Reasons Not to Use Landscape Fabric

A garden bed with landscape fabric

1. Landscape Fabric is Bad for the Soil

Landscape fabric blocks nutrients from reaching the soil when your mulch decomposes. Those valuable nutrients go to waste. They just sit on top of the fabric. The mulch also won’t degrade as fast because the beneficial microorganisms in the soil have a harder time reaching the mulch. 

Over time, your plants use up the available nutrients in the soil and they won’t be replenished. The soil will become less fertile because it will be nutrient deficient. You will have to fertilize to restore some nutrients.

Landscape fabric also reduces the amount of air and water that reaches the soil. The fabric is perforated so some air and water can pass through. The problem is that these holes can get blocked with soil and decaying organic matter. This reduces the amount of air and rain that can reach the soil. Plants’ roots need both water and oxygen to grow. When the soil moisture level is too low, your plants won’t grow well. 

The soil under the landscape fabric will also have fewer beneficial organisms in it. For example, earthworms have to come to the surface periodically. They can’t easily reach the surface when it’s covered with landscape fabric. Worms help bring oxygen into the soil by creating tunnels. They also improve drainage and reduce soil compaction. In addition, they help process decaying matter. The soil quality will be lower without them.  

The soil can also compact over time when it’s covered in landscape fabric. You can’t till it or aerate it without removing the fabric. When soil is compacted, plants have a harder time spreading their roots. 

Over time, it will be harder to grow plants in the soil under the fabric. The plants that do grow won’t be as healthy. 

2. Landscape Fabric Only Blocks Weeds For a Short Amount of Time

When you first install your landscape fabric, it will keep the weeds down. It will smother existing weeds that are growing. The weed seeds that are already in the soil won’t be able to germinate and grow because they won’t receive any sunlight.

The problem is that the mulch that you put on top of the fabric will decay over time. Leaves can also drop on the mulch and decay. Dust can be blown in. After a couple of years, you’ll have around an inch of nutrient rich soil on top of your landscape fabric. 

Weed seeds will be blown in by the wind and land on top of the mulch. Most weed seeds are actually blown in. They aren’t already in the soil. Birds and rabbits can also drop weed seeds on top of your flower beds.

Eventually, weeds will start growing out of the layer of soil on top of your landscape fabric. Weeds can actually start to grow as soon as 6 months after installing landscape fabric. 

When weeds start to sprout, you’ll have to start weeding or you’ll have to replace the landscape fabric and put fresh mulch on top. The weeds may not be as bad for the first couple of years but you will still have to do some weeding. It’s not a permanent fix. 

It is also possible for weeds to grow through landscape fabric. Weeds can grow in the holes you make for your plants. Sometimes, weeds can grow in the perforations in the fabric.

In most cases, landscape fabric isn’t necessary. A good layer of mulch will do the job of landscape fabric. Weeds have a hard time pushing through 2-4 inches of mulch. The mulch also blocks the seeds from reaching the soil. Wood chips and bark can last a long time. 

Pulling weeds
Pulling weeds is harder with landscape fabric.

3. Landscape Fabric Makes it Harder to Weed

Eventually, weeds will start to grow in your mulch on top of your landscape fabric. Some particularly strong weeds can actually grow through landscape fabric. The roots can make their way through the perforations or actually penetrate it the fabric. 

Weeds that grow through the landscape fabric are extremely difficult to remove. This is because the plant roots get tangled in the fabric. Removing them will tear your fabric and make it easier for more weeds to grow. It will also make a mess of your garden. 

Sometimes you won’t get all of the roots with the weeds because they get stuck in the fabric. These roots can keep growing. New weeds will sprout up quickly. Once the root system is established under the landscape fabric, it is very difficult to get rid of. 

Eventually, you’ll just have to remove the old landscape fabric and replace it. This is a big job that you’ll have to deal with every couple of years if you want to keep your garden weed-free. 

4. It’s Unattractive

Landscape fabric does not degrade like mulch. It’s made from inorganic material. Over time, the fabric will get torn. Roots will grow through it. You might accidentally tear it while weeding or digging in your garden. After a couple of years, it will be a tattered mess. It becomes an eyesore in your flower garden. To fix it, you’ll have to replace it.

Landscape fabric is also slippery. Mulch can easily slide off it. Sometimes mulch shifts during a storm if there are strong winds or flooding. Mulch can also slide downhill if your garden is on a slope. Pets and foot traffic can also displace mulch. 

Chances are, your landscape fabric will start showing through your mulch at some point. This is one of the main reasons I no longer use landscaping fabric in my yard. It’s ugly. I don’t like looking at it. It’s also a hassle to move the mulch back onto the fabric after it shifts. 

5. Landscape Fabric Makes it Harder to Change Your Landscape Design

Landscape fabric makes it difficult to add new plants to your garden. You’ll have to cut a hole in the fabric to plant a new plant.  

If you decide to move a plant because it’s grown too big or because it’s not getting enough light, you’ll have to remove the fabric around the plant. You’ll have to cut a large hole to get the root structure out. You’ll then have to cut another big hole where you want to put the plant. 

When you cut a bunch of holes in your landscape fabric, it will become less effective at keeping the weeds down. It will also start to tatter and fray around the holes. You’ll have to replace it eventually. If you plan on adding plants or moving plants, you should avoid landscape fabric. 

Weeding a garden

6. It’s not Environmentally Friendly

Landscape fabric is made from plastic. It is a petroleum product. Over time, the landscape fabric can introduce microplastics into your soil as it degrades. It also isn’t a recyclable material. It will end up in a landfill eventually.

It’s not great for the environment to put a bunch of plastic in your yard. If you’re trying to garden in an environmentally friendly manner, skip the landscape fabric and just use a thick layer of organic mulch. 

7. Some Plants Can’t Grow Properly

The landscape fabric will prevent some plants from growing properly. As perennial plants grow wider, the landscape fabric can tighten around them. Plants that creep or spread can spread roots into the landscape fabric and under it. Some parts of your plants can get trapped under the fabric. 

This limits your plant’s growth. They can’t grow freely. It will also tear up the landscape fabric over time and make your plants difficult to move. The roots will get stuck in the fabric. 

8. Tree Roots Can Grow Under and Through Landscape Fabric

Another problem you may encounter is tree roots spreading under the landscape fabric. This is an issue with trees that tend to send suckers. The roots will find any hole or tear in your fabric and poke through. 

Once they sprout, they are incredibly difficult to get rid of. You may have to pull the landscape fabric up and dig along the root line to the main tree to get all of the root growth out. If you don’t dig it out, it will just continue to grow. 

Reasons To Use Landscape Fabric

a rock mulch garden

Landscape fabric prevents rock mulch from mixing with the soil

There is one place where it is recommended to install landscaping fabric. That is under inorganic mulches like rock mulch or rubber mulch. If you plan to install lava rock, river rock, pea gravel, or rubber chips, it’s a good idea to install landscaping fabric under them to prevent the rocks from sinking into the soil.

If you don’t install landscape fabric under rock mulch, the rocks will sink in and mix with the soil over time. Heavy rains and foot traffic will cause them to sink in. Eventually, they will need to be replenished. The rocks will also be difficult to remove if you decide you want to change your landscape design. Landscape fabric makes sure the rocks stay on the surface so they can be removed. 

There is one major drawback. Over time, weeds will start to grow in the rock mulch. Debris will make its way into your rock beds. Leaves may fall on it and break down. Dust can blow in. Slowly, a layer of organic material will build up under the rock and on top of the landscape fabric. Weed seeds will also blow in or be dropped by birds. Eventually, weeds will start to sprout out of the rock mulch. The roots can grow into the fabric. This makes the weeds difficult to remove. 

To avoid this, you’ll have to keep your rock mulch clean. When leaves fall on it, get your leaf blower out and clean them off. Don’t allow them to break down into the rocks. Organic matter will build up but keeping the mulch clean will slow down the process. Eventually, you’ll have to remove the rocks and landscape fabric and do a thorough cleaning to keep your beds weed-free. It’s a big job. 

A garden bed with wood chips

A couple of years ago, my parents paid a lot of money for a landscaper to install some nice rock mulch on their beds in their front yard. It looked beautiful for about a year. Unfortunately, they didn’t keep it clean and weeds started to grow the following year. It was a big job to clean it out. 

For more info, check out my guide to rock vs mulch. 

Landscape fabric can help your mulch last longer

Some gardeners choose to install landscape fabric to increase the lifespan of their mulch. Landscape fabric prevents microorganisms in the soil from reaching your mulch. As a result, the mulch won’t break down quite as fast. 

You might only have to apply a fresh layer once every 1.5 years instead of every year. This can save you a bit of money over time. The mulch might also look nicer for longer. 

Of course, the mulch will still break down, even when you use landscape fabric. It will still weather and decompose. Just at a slightly slower rate. 

An Alternative to Landscape Fabric

If you have garden areas that are completely infested by weeds, one solution is to lay cardboard over them to smother the weeds. Cardboard can also be used to kill off grass. It’s a great tool to reclaim a garden that has been overtaken by weeds or start a new garden where there is currently grass. You can use corrugated or regular cardboard. Newspaper can also be used.

Simply lay the cardboard over the weeds that you want to kill off. Lay some mulch on top of the cardboard. You could use wood chips or a more nutrient rich mulch like compost, straw, or shredded leaves. 

The cardboard smothers the weeds. Over time, the cardboard is broken down by microorganisms in the soil. It doesn’t stick around forever like landscape fabric. It will kill the majority of the weeds. After the cardboard decays away, weeds can start growing back.

The cardboard will last anywhere from 6 months to 2 years. Exactly how long it lasts depends on the climate, the soil quality, the thickness of the cardboard layer, and the amount of precipitation you get.   

When choosing cardboard to apply, look for a non glossy variety with minimal ink. Remove any packaging tape, staples, etc. Lay the cardboard over your beds. Use 1 or 2 layers depending on the thickness of the cardboard. Lay the cardboard over the weeds. Make sure there are no holes. Cover the cardboard with a thick layer of mulch. Wood mulch and bark mulch work well. Pine needles, grass clippings, or straw can also be good options.

My Experience

When I bought my current home, it had landscape fabric in most of the garden beds. I didn’t mind it at first but it quickly started to show through the mulch. Some sections were tattered and torn. I also had trouble planting in it. It was a hassle. 

I really didn’t want to remove it because I knew it would be a massive job. Eventually, I had to because it was becoming such an eyesore. 

I cleaned the mulch off the top and tore it up. After, I tilled the soil to loosen it up. It had become pretty compacted. Next, I applied a healthy layer of compost on top of the soil to restore some nutrients. After that, I planted my plants and added a fresh layer of cedar mulch. I used straw mulch in my vegetable garden. 

It’s always a good idea to mulch. Mulch can help with erosion control. It can help regulate soil temperature. It can also help retain moisture and block weeds. 

Before you install landscape fabric, consider whether or not you actually need it. Keep in mind that you will still need to weed, even if you install landscape fabric. It will also block valuable nutrients from reaching the soil. It will also look unattractive as it ages and wears. 

Landscape fabric can be a fine ground cover. It can help control weeds if you have a serious weed problem but it’s usually not necessary. There are better solutions. The only time when landscape fabric is recommended is when you’re using rock mulch. It will prevent the rocks from mixing with the soil.

Eventually, organic matter will accumulate on top of the landscape fabric and weeds will sprout. There is really no avoiding this. You will always have to deal with weeds. If you stay on top of them, they aren’t that big of a deal. Landscape fabric can be helpful in the short term but in the long term it will be more work to maintain. 

Do you use landscape fabric? Share your experience in the comments below!

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Should I Use Landscape Fabric Under Mulch?

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