Examining Landscape Fabric: To Use or Not To Use?
By Ellen Rubin
There are some places where using plastics is useful, even in our gardens. Places where they serve a purpose are irrigation, hosing, buckets, and lighter-weight carts/wheelbarrows.
What I don’t accept is that petrochemicals should be part of our gardens in the form of artificial turf or landscape fabric. Artificial turf was discussed previously, but now we’ll explore the negative impact of using landscape fabric in our yards, circumstances where you may want to use it, and safer, more effective alternatives.
I reluctantly admit that many, many years ago I fell into the trap of using landscaping fabric and that I can personally attest to all the negatives I talk about. I can also honestly say that too many people are still buying and using it. I’ve worked at a big box garden department and a local nursery where one of the most sought-after items was landscape fabric. At the big box store it was constantly sold out.
Most of the time people use landscape fabric thinking it will cut down on the need to weed their gardens. In the long-run, the fabric proves to be counterproductive for weed control and does more harm than good to your garden plants, soil health, and is environmentally hazardous for the air, water, land, and even human health.
What is Landscape Fabric and How Does it Work?
Landscape fabric can also be referred to as weed barrier fabric, weed cloth, or geo-textile. I’m using the term to refer to the fabric made from petrochemicals and not organic alternatives like burlap. It was developed as a generally permeable textile that allows water, air, and nutrients to reach plants while preventing weeds from growing by blocking the sun so seeds can’t germinate. Other proclaimed attributes are that it minimizes soil erosion and is supposed to help gardeners save time and effort while enhancing the aesthetics of the garden.
Landscape fabric comes in rolls ranging from 3 feet in width to 15 feet. You can buy it prepackaged or if you visit local nurseries, you can be purchased by the linear foot. You also need to purchase staples. These are usually metal pieces to be used around the perimeter of the fabric to hold it in place. If your area is larger than the fabric width, each sheet should be overlapped at least 3 inches and tacked down to ensure that weeds don’t sneak between sheets. The fabric comes in black, or sometimes brown. It’s generally anticipated that some type of mulch will be placed over the fabric in your garden to mask its appearance and acts as a barrier between the mulch and soil.
Fabric is available in different materials and weights/thicknesses. The overwhelming majority are made from either plastic or polypropylene, both petroleum-based products. Plastic sheeting is much worse for your garden and the environment. Polypropylene, a thermoplastic polymer, is generally considered a safer material than plain plastic. (We’ll discuss this in more detail below.) When shopping for fabric you may find the following options:
- Woven fabric is the most commonly available and is used to block weeds around trees and shrubs. It’s highly durable, and made from finely laced threads of polypropylene. It allows water and nutrients to permeate the surface. It can also be made from thin strips of plastic or spun polyester fibers.
- Non-woven polyester or polypropylene fabrics are good for soil stabilization. Unless you are using it under gravel pathways, look for a fabric that is perforated so that water and nutrients can seep through.
- Spun bonded landscape fabric has bonded polypropylene fibers and is often what you find in heavy-duty landscape fabric. This balances very durable fabric that still has a measure of permeability if you are using lighter-weight versions. The heavy-weight options can become impermeable and are useful for irrigation, drainage, and retaining wall applications to help keep roots out and prevent seepage. Spun bonded fabric is very difficult to tear.
- Perforated landscape fabric has small holes punched in it for further permeability. These options are often very lightweight and less expensive. Some have pre-cut or burned holes set at regular intervals for plantings.
- Plastic is sometimes used instead of polypropylene “landscape fabric.” While it is less expensive, it doesn’t allow moisture and nutrients to pass through to the soil. Yes, it does inhibit any type of plant growth, but it’s very bad for soil health.
There is usually an inverse correlation between durability and permeability. Lighter weight fabrics let more nutrients, air, and water reach the soil, but they are less durable. Something that will last many years may not be suitable for growing plants because it smothers the soil ecosystem by denying it nutrients, air, and water.
Regardless of which fabric you choose, nothing made of fossil fuels is biodegradable or recyclable, yet all degrade over time and most fabric has a maximum useful life no more than 10 years. It is affected by exposure to sunlight, temperature fluctuations, and other environmental factors. This is especially true for lighter weight fabrics that are less expensive and easier to install, but won’t last as long. You’re also more likely to get breakthrough weeds with inexpensive versions. All of these fabrics are flammable so make sure they aren’t situated anyplace there might be an open flame; for instance, near fire pits.
Beeblebrox – Own work
Source
Is Landscape Fabric Effective at Blocking Weeds?
In my experience, most people purchase fabric because they believe it will save them the time and trouble of pulling weeds that sprout in their yards. Unfortunately, this is partially false advertising. Yes, in the very short term it will block some weeds from germinating if the seeds are already in the soil. However, you will eventually get weeds.
The toughest weeds, like thistles, and shoots from trees such as aspens or crabapples will grow through most fabrics. Even when you don’t get growth that breaks through the fabric, you will have weeds that grow on top of it. In some instances, dust, dirt, compost, or mulch that blows or forms on top of the fabric over the course of a year or two not only blocks perforations, but creates enough of a base that seeds can sprout on top of the fabric.
Whether weeds grow from beneath or above the fabric, their roots become enmeshed in it and pulling them out becomes more difficult, not easier, than pulling out of soil alone. I’ve had fights with clover and thistles where the fabric was more hinderance than help. I’ve also run across weeds that grow in the smallest of gaps, whether that’s from between fabric sheets, where it may be ripped from previous weeding, or in the X slashes where something was planted. In those cases, you are dealing with trying to pull weeds that are under or next to a plant where their root structures become entangled. None of this makes your life easier.
Regardless of how the weeds get there, removing them becomes more difficult with fabric in place. You either have to carefully disentangle the roots from the fabric if it started growing from the top down, or pull the weed from it if it’s growing through the fabric. Either way, you end up ripping the fabric and leaving a hole which negates its effectiveness in that area.
Using landscape fabric also means that you must use some type of mulch to cover it. The black fabric absorbs sunlight and super-heats the ground below which would kill the beneficial microbes and insects that live in our soil.
Rather than saving you time or money, putting down landscape fabric actually increases your expenses; either for the necessary mulch or the extra time it takes to disentangle weeds, and/or repair holes. Fabric is not a one and done type of deal.
Effects of Landscape Fabric on the Soil
As landscape fabric ages, the clogged pores not only allow weeds to grow on top, but it prevents the necessary trifecta of air, water, and nutrients from reaching the soil. The fabric becomes an impermeable petrochemical barrier that interrupts the ground’s relationship with sun, moisture, and air flow, eventually smothering everything that lives below. This includes beneficial insects, earthworms, and microbes that are all essential to plant growth. The soil becomes compacted, dry, hardened, and unhealthy. What was meant to inhibit weeds that rob nearby plants of water and nutrients eventually suffocates the plants’ roots leading to stunted growth or death.
Using landscape fabric and creating a good water balance is almost impossible. If you live in an arid area, you might think that you can rely on the fabric to help retain moisture. That argument assumes the fabric pores don’t become clogged and doesn’t take into account that having fabric in place already reduces the amount of water that can even reach the soil. If you water or get rain, only a fraction of the water will actually reach the soil. The same can be said of the flow of oxygen. Laying fabric will significantly reduce, or cut off, the flow of oxygen to microorganisms, fungi, and root structures.
Fabric also causes the inverse problem. Like plastic sheeting, if the fabric becomes an impermeable barrier while the surrounding ground is water logged, the soil can’t dry out. This leads to root rot, possible insect infestations, and would drown beneficial earthworms.
Having a barrier between decomposing plant matter that falls from, or blows onto, your garden also prevents the soil from being nourished. You can also forget about adding compost to enrich your soil. Even using some type of fertilizer becomes more difficult. If it is water based, how much will even reach the soil rather than just pool on the surface? Using spikes would require you to punch holes in the fabric. Granules may not dissolve properly to be able to find its way through pores.
What will reach the soil are the chemicals inherent in the fabric, and microplastics that flake off as the fabric degrades. Eventually, microplastics will find their way to groundwater and into your plant’s circulatory system. The same chemicals used to create UV protection for the fabric are the chemicals that harm your plants. Using landscape fabric around edible plants is definitely NOT recommended. If you want to cut down on the weeds around your food crops, alternatives are discussed below. A big hint about the toxicity of fabric is that it’s recommended that you wear personal protection gear such as gloves and a mask when you are cutting and laying it because it can lead to respiratory or skin irritation.
There are a couple other reasons not to use landscape fabric, especially if you are an enthusiastic gardener. First, it makes planting anything new, like you often do in ornamental gardens, much more difficult. Also, it’s not uncommon to need to divide or move plants that you already have. I’ve done it frequently with things like hostas, bulbs, or irises. Sometimes, you just discover that your original planting location isn’t a happy place for a certain specimen or it’s outgrown its location. Landscape fabric complicates this to no end. You have to rip or cut the fabric that’s down to dig things up, then somehow repair that area and cut a hole/slit where you want to replant things. This is much more complicated than it needs to be.
You’re also denying yourself of the joy of watching some plants self-seed. I’ve had great luck with California poppies, pansies/violas, and lupines self-seeding. It’s a great way to fill in a garden, especially if you are trying to build a meadow landscape or re-wilding an area. It not only saves you time and money spent buying new plants and planting them, but it’s also the surprise of seeing what grows, especially if you have some cross pollination and get new color combinations.
Alternatives to Landscape Fabric
There are times when having some sort of weed barrier is useful, especially in food gardens where you don’t want to disturb the soil to weed. You also want to save the time and energy needed to weed. You still have several options without resorting to plastic-based landscape fabric. Instead, look to natural sources such as newspaper, cardboard, or burlap that you can put underneath mulch. Many people find a layer of straw useful. All of these choices are much more sustainable, and will slowly decompose and add nutrients back into your soil. You can also make some weeds your friends. Dandelions are edible and attract pollinators, especially early in the season. You may choose to fill in your vegetable garden with companion plants and herbs, or embrace square foot gardening that crowds out excessive weeds.
Final Thoughts…
Regardless of how you choose to address weed growth: mulching, manual weeding, compact planting, or just accepting a certain level of weeds, using landscape fabric is not your best option. Avoid the damage to your soil’s ecosystem, and save your time and money. Adding petrochemical products to your garden is not a good long-term solution for you, your garden, or the environment.