By Finn Beckman, Gardener | The Gardens on Spring Creek
Landscaping fabric (or weed barrier) is a common solution for weeds in the garden. But what exactly IS this fabric? Most weed blockers are made from some form of synthetic polymer, most commonly polypropylene (PP), also used in many products, from hinges to bottles.
Broadly speaking, there are two main types of weed barrier: impermeable and woven. Impermeability is sometimes touted as a benefit, since weeds can’t emerge through a non-permeable membrane, but the use of an impermeable plastic on the soil’s surface creates several challenges. Top of the list—it stops the movement of many needed resources, like liquids, gases, solids, and light. As a result, many nutrients moving down the soil will be stopped, and water will pool on the top of the fabric instead of being absorbed by the ground. This interrupts the natural flow of resources around the garden and starves plants of these essential elements. Even woven fabrics (still made from plastics) reduce water and air exchange with soils. But the troubles don’t end there.
The main point of landscaping fabric is to block weeds, right? Unfortunately, the mulch placed on top of the fabric—along with small amounts of trapped, windblown soil particles—can act as media for weeds or other plants to grow in. This is a stepping stone for plants to root through the fabric and get tangled within. Additionally, weed fabric has a lifespan ranging anywhere from two to twenty years, at which time it must be replaced to remain effective. Removing and replacing landscape fabric is no easy task. First, the protective mulch covering must be removed. Then, the fabric, full of years of dirt, dust, and penetrating roots, must be peeled back and rolled up to be disposed of. Given that these barriers are made from plastics, it’s also likely that they leave behind microplastics in the soils they cover. At the end of their lifespans, these fabrics must be taken to a landfill.
Since these fabrics are marketed as the end-all, be-all to weeds, having to replace them on a rolling basis isn’t what most folks think of when making the decision to put them down at home. Since these fabrics reduce air and water movement into soils, they don’t make a good growing environment for the plants they are meant to protect. So, unfortunately, the fabric can be more destructive than supportive of the garden.
Is there a good use for landscaping fabric? Yes! The two main locations to use fabric are pathways and very large areas. Paths can be tedious to maintain, and using landscaping fabric as a base can prevent any seeds from the seed bank from emerging. They can also prevent any paving material from sinking into the soil. Many farmers and larger-scale growers use more industrial versions that can cover wide swaths of land used for production. These fabrics are either thicker or replaced more regularly (an easier task in a farm field without mulch, and with the help of a tractor). Additionally, a weed barrier is great for redirecting excess water into proper water management systems, such as drains or retention areas, to help mitigate soggy paths and soils in problem spots.
Ultimately, landscaping fabric has its place in a gardener’s toolbox of solutions but needs to be properly placed to create the highest chance of success. While weed barriers can prove useful for high traffic paths and areas too large to use effective weed management strategies, keep in mind that if used elsewhere, you may be preventing nutrients, water, light, and air from translocating around the garden—resulting in unintended consequences.
What to use instead? Mulch—organic or inorganic—is a far more effective choice than fabric. Plus, because it’s so customizable, mulch not only helps keep weeds at bay but also enhances your garden’s overall aesthetic!
