Skip to Content

How to Use Cardboard as a Weed Barrier: How Well Does It Work?

Cardboard is a popular form of weed barrier that can be used to help prevent weed growth in areas that you plan to cultivate later in the year. Cardboard works well as a weed barrier in some aspects, but it can also pose some gardening challenges too.

To use cardboard as a weed barrier lay the cardboard out over the soil. Where the cardboard overlaps, make sure it overlaps at least 6 inches. Wet the cardboard down and place a layer of mulch or other covering over it.

Below you’ll find a guide on using cardboard as a weed barrier as well as a breakdown of how effective it is compared to other weed barrier types. Keep reading to learn more about how to install a cardboard weed barrier and how to get the most out of it in your gardens and borders.

How to Use a Cardboard Weed Barrier

Cardboard is used as a weed barrier by installing large panels of cardboard across the garden plots or landscaping borders that need weed prevention.

Cardboard weed barriers work by limiting the amount of sunlight that the soil receives. The weed barrier prevents any dormant weed seeds present in the soil from receiving the sunlight they need to germinate.

Cardboard weed barriers can also help prevent new weed seeds from being deposited in bare soil during the fallow parts of the year.

A layer of cardboard over the soil reduces the number of new weeds that need to be pulled from the garden plot in the following season.

Here’s a video showing some benefits of using cardboard for weed barrier:

Check out these Professional Quality Weed Barrier and Weed Barrier Stakes from Amazon to see the most current selection and pricing.

Installing a Cardboard Weed Barrier Step-by-Step

The process of installing a cardboard weed barrier is simple since cardboard is a material that is cheap and easily accessible.

An important fact to consider is that cardboard and corrugated cardboard are two different types of material. Corrugated cardboard breaks down much more slowly than regular cardboard, and is not suitable for a cardboard weed barrier.

A good alternative to corrugated cardboard is Chipboard Found Here from Amazon, which breaks down more easily.

To install a cardboard weed barrier, perform the following steps:

  • Gather the cardboard. Be sure when you’re sourcing your cardboard weed barrier that you have standard cardboard and not corrugated cardboard.
  • Lay the cardboard down over the soil. Put the cardboard in a single layer across the top of the ground in every part of the garden where you don’t want weeds to access.
  • Overlap the cardboard in the garden. Making sure there is an overlap on each section of cardboard of about six to eight inches to prevent sunlight from reaching the soil.
  • Wet the cardboard down. After the layer of cardboard has been laid down in the garden, take a hose or sprinkler system and wet the cardboard down thoroughly.
  • Add a layer of compost and mulch. Adding compost and mulch over the wet cardboard helps it break down, provides nutrition for the garden bed, and also provides extra protection against sunlight hitting any dormant weed seeds.

Once you’ve added compost and mulch as a topper on your cardboard weed barrier, the garden plot is ready to lay fallow until you are prepared to cultivate the soil in the following six to twelve months.

How Well Does a Cardboard Weed Barrier Work?

A cardboard weed barrier is an effective long-term barrier against weeds if it is laid during the right time of the year and is installed correctly.

People who intend to use a cardboard weed barrier should keep in mind that a cardboard weed barrier takes six to twelve months to decompose into soil, so it needs to be installed well ahead of any planting activities.

Cardboard weed barriers also need to be kept damp throughout the fallow season. This helps the cardboard break down faster and encourages the growth of beneficial bacteria.

Can You Use Cardboard Instead of Landscaping Fabric?

A cardboard weed barrier is an effective substitute for landscaping fabric and is actually preferable since it can be utilized by earthworms and other garden-friendly microbes to improve the condition of the soil.

Compared to a cardboard weed barrier, landscaping fabric can become less and less effective at allowing air and water into the soil over time as they become clogged with soil.

Cardboard weed barriers improve over time as they break down.

By attracting beneficial garden animals such as earthworms and bacteria, cardboard weed barriers help the soil ultimately produce a better crop when it is planted.

Is It Safe to Use Cardboard as a Weed Barrier?

Cardboard is considered a very safe form of weed barrier in the garden because it decomposes completely into the soil.

Cardboard is also preferable to other types of weed barriers such as herbicides because if proper cardboard is used, it does not release any kind of toxic chemicals into the environment.

Since many herbicides used to destroy weeds in the garden can be dangerous around children and small animals, a cardboard weed barrier is a much gentler and safer solution.

Tips for Using a Cardboard Weed Barrier

The trick to getting the most effectiveness out of a cardboard weed barrier is to use it right. Check out these tips for optimizing your garden’s cardboard weed barriers:

  • Maintenance is key. Making sure to maintain your cardboard weed barrier by replacing lost mulch and keeping the area well-watered can prevent infestation from pests such as termites and voles.
  • Choose the right time of year to install. The garden plot won’t be plant-able for up to twelve months after the weed barrier is installed, so this method for placing a weed barrier is useful for winterizing garden plots or prepping new ones.
  • Remove tapes and labels from cardboard before using it as a weed barrier. These materials may have toxic chemicals that will break down in the soil when the cardboard decomposes. Cardboard should preferably be clean of ink or other chemicals.

People who have a hard time with a cardboard weed barrier in the garden are usually guilty of not installing it right, or installing it during the wrong time of year.

Following the guide above will ensure that your cardboard weed barrier works well and helps maintain good soil conditions all season long.

Check out these Professional Quality Weed Barrier and Weed Barrier Stakes from Amazon to see the most current selection and pricing.

Cardboard is an Effective Weed Barrier in the Garden

Along with being economical and easy to find, cardboard as a weed barrier is an effective, organic way to prevent weeds from overtaking your garden in the off-season.

Sharing is caring!