There’s a long-standing belief that putting landscape fabric or weed barrier over the soil will prevent weeds. While it may work temporarily in some situations, there are many reasons it’s a particularly bad idea in the desert landscape.
The use of landscape fabric or weed barrier is considered controversial, but it shouldn’t be. It’s flat-out a bad idea, especially when used in the desert southwest.
Here are the many ways it harms plants and soil, and creates more work rather than less for desert gardeners.
It Doesn’t Prevent Weeds!
The purpose of landscape fabric is to prevent weeds, but, ironically, it doesn’t do a very good job of it.
After a season or two, weeds start to grow wherever there’s a gap — along the edges and seams, and around cutouts for plants, irrigation emitters, outdoor lights, boulders, and any other stationary objects.
Additionally, as wind-born seeds land on your gravel or mulch, they sprout and grow on top of the fabric.
Either way, the weeds’ roots become enmeshed in the fabric which makes them harder to pull.
It’s Bad for Your Plants & Soil
There are numerous ways landscape fabric is detrimental to desert plants and the health of desert soil.
It holds in heat. As if your plants don’t get hot enough!
It leads to soil compaction. As anyone who has dug a hole can attest, most desert soil is already extremely compacted.
It hinders the flow of gases such as oxygen and carbon dioxide in and out of the soil. Plant roots need oxygen!
It disrupts the flow of water. Some water will penetrate, but some will flow along the top of the fabric, especially as it gets clogged with dirt and roots.
And once water is in the ground, fabric prevents evaporation. This can be a problem for cactus, agaves, desert natives, or any plant prone to root rot during the rainy season.
By forming a barrier between the worlds above and below the soil, landscape fabric prevents any new organic matter from entering the soil. This means no additional nutrients or humus are added, and the soil gets depleted over time.
Desert soils are high in minerals but contain less than 1% organic matter.
Healthy soil is teaming with life — bacteria, fungi, protozoa, nematodes, earthworms, and insects. One gram of soil may harbor up to 10 billion microorganisms of possibly thousands of different species! But landscape fabric creates inhospitable conditions for these critical organisms.
Landscape fabric is suspected of killing or repelling earthworms. Some gardeners report that there are none to be found under it.
It’s Makes Gardening Less Enjoyable
Some people like to “set and forget” their yards. But if you love to make changes in your garden — add, divide, move, or remove plants — landscape fabric will be in your way.
Every time you want to add a new plant, you’ll need to cut a hole in the fabric. And every time you remove a plant, you’ll leave a significant gap.
If you want to move plants grown near landscape fabric, you’ll find their top layer of roots entwined with the fabric. It’s hard on plants to have their roots disturbed this way.
If you’ve scattered wildflower seeds about, landscape fabric will make it less likely that they’ll grow. And you’ll be less likely to have volunteers in your yard. Some of my most successful plants just “showed up”. I would miss having the occasional free plant.
It Can Be Expensive
Depending on the size of your yard, you could easily spend hundreds, if not thousands, of dollars covering it with landscape fabric, especially if you hire someone to lay it for you.
Homewyse.com has a basic calculator you can use to get an idea of how much landscape fabric will cost depending on the size of your job and whether or not you do it yourself.
It’s a Pain to Put Down
Putting down landscape fabric is a real chore, especially if you’re not starting with a blank canvas.
First, you’ll have to remove any existing mulch or gravel. A typical suburban desert yard is covered with literally tons of gravel. (Our new home came with bare soil. We needed 5 tons of gravel to cover our modest size backyard.)
Next, you’ll have to lay down the fabric, cutting around any existing plants and objects. Then you’ll have to put the mulch or gravel back. It can be quite an ordeal.
It’s Plastic and Doesn’t Last
Landscape fabric is made of plastic. The negative effects of plastic on the world and human health are well documented. Plastic in the soil is particularly worrisome if you’re growing any edibles — fruit trees, herbs, or vegetables.
Landscape fabric starts breaking down after a few years, especially in our broiling heat and baking sun. Then, you’re faced with the decision of whether to remove it and start anew or just remove it for good. Most homeowners and gardeners regret their decision and are glad to be rid of it.
Have you used landscape fabric in the desert?
Was it a “hit” or a “miss” in your garden?
Please share your experience in the comments below!
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Author Bio
Deane Alban is the creator of Southwest Gardener. She is a science writer with a bachelor’s degree in botany from the University of South Florida. Gardening is her lifelong passion. She’s been gardening in Tucson for 15 years.
