Landscape Fabric: A Good or Bad Choice for Weed Control

Eroded mulch exposes the fabric and allows weeds to grow on the surface. Photo by Ralph Morini.

By Ralph Morini
Piedmont Master Gardener 

In the never-ending battle against weeds, gardeners may be tempted to turn to landscape fabric as a line of defense. The idea of applying what appears to be a relatively permanent solution to stopping weed growth is appealing, but there are drawbacks. 

Does landscape fabric do what it claims?

The landscape fabric typically used in non-agricultural gardens is a woven plastic or a spun polyester cloth. It is marketed with claims of a long-term ability to suppress weeds while allowing air and water to permeate through it, providing a good soil environment for plants. It is sold in rolls at garden centers and is widely used by commercial landscapers. 

Landscape fabric can offer short-term weed management when installed directly on the soil and covered with an organic mulch, but don’t be misled into thinking this is a “forever” solution. Its claims about water and air penetration are valid, initially. However, the fabric becomes progressively clogged with soil particles, diminishing air and water permeability and damaging the health of the soil below. Eventually some weeds from the soil beneath the fabric will break through and grow anyway. And, weed seeds blowing onto the surface mulch—or brought in on tools, shoes or deer hooves—will germinate above the fabric as the mulch breaks down. 

If the mulch is the finely ground type commonly used commercially, it decomposes during the first year, allowing surface seeds to grow above the fabric. To make matters worse, roots from surface weeds can penetrate downward through the fabric, creating a weed-pulling challenge that can yank the fabric to the surface, creating coverage and appearance issues. In addition, trying to plant through the fabric requires cutting into it, which is frustrating at best. Finally, the fabric degrades when exposed to the sun, ultimately depositing plastic into the soil, or it is discarded and ends up as another piece of synthetic material in the landfill.

I came across a classic example in a neighbor’s yard. The bed was covered with landscape fabric and then mulched with two inches of finely ground hardwood a little less than two years ago. Over that time, the mulch decomposed and eroded, exposing the fabric. Weed seeds germinated in the remaining mulch, and the roots grew through the fabric into the soil below. Bottom line: landscape fabric is at best a short-term weed deterrent that is cursed with many longer-term issues. 

What are the best weed control options?

Weeds are tough survivors, but there are desirable ways to minimize weeds in the garden that are effective if applied carefully and renewed as needed. 

For example, a thick organic mulch will suppress weed growth if existing weeds are removed mechanically before the mulch is laid down. I have had success using a stirrup hoe to cut weeds slightly below the soil surface and below the plant crown. This kills most of the weeds and leaves the organic matter from their roots to decompose in the soil.

A more aggressive option is to cover the bed with newspaper, at least six to eight sheets thick and overlapping a bit, and then mulch generously on top of it. This provides a short-term weed barrier that will ultimately allow air, water and critters to move through to the soil surface. As the newspaper and mulch decompose, they will add organic matter and nutrients to the soil. Select the newspaper with some care. Color printing is okay, but don’t use glossy paper; it has too many undesirable components. Rolls of biodegradable landscape or construction paper barriers are also appearing in home improvement and garden supply stores as the public desire to keep plastic out of the soil increases.

Over time the fabric becomes clogged with soil particles, diminishing air and water permeability and damaging soil health below. Photo by Ralph Morini.

Single-thickness cardboard, overlapped to avoid gaps for weeds to pass through, is another potential weed barrier. It takes longer to decompose than the newsprint but will break down in a year or two. Moisten the ground and the cardboard prior to adding mulch. Be sure to remove plastic tape and labels from cardboard, and again, don’t use any glossy product.

As a mulch, coarsely ground wood chips or arborist waste will provide a longer lasting cover than finely ground wood mulches. When a thick layer is applied (experts suggest three to six inches), it protects against extensive weed growth, although it must be supplemented with more chips, typically annually. Most commercial landscapers seem to use the fine-ground mulch materials that look nice and smell good but decompose quickly and succumb to surface-seed-generated weed growth within the first year. Coarser chips may be less stylish, but they offer better air and moisture permeability and a significantly longer life.

Other mulch possibilities include pine needles, straw and shredded leaves. They break down faster than wood chips and have a different aesthetic but can help restrain weed growth, especially if a layer of four to six inches thick is applied. Plastic and rubber mulches should be avoided. Likewise, rock mulches will not afford the benefits of organic mulches that break down and strengthen the soil. 

There are no permanent solutions. 

Weed growth is basically inevitable over time. Non-organic landscape fabric may start off as an effective deterrent, but eventually it leads to weed germination problems and forms an impermeable barrier that increases runoff and degrades the underlying soil structure needed for healthy plants. Organic material, reapplied and regroomed periodically, provides the best path to long-term gardening success. To learn more, check out these websites: 

From Penn State Extension: 

From Illinois Extension: 2021-06-25-disadvantages-landscape-fabric

From NC Cooperative Extension: the-appropriate-use-of-landscape-fabric/ 

From Washington State University: 2015/03/landscape-fabric.pdf


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