Weed Barrier Fabric is a Weed

By Mike Lorenc, Conservation Garden Park

If you’re a frequent reader of this column you have likely encountered one particular reoccurring piece of advice; please don’t use weed barrier fabric. This nugget of advice has proven rather controversial so today we’ll make the case against the use of weed barrier fabric and show a healthier alternative approach.

Reasons NOT to use weed barrier fabric:

Reason 1: It doesn’t work. Yep, you read that right, it doesn’t even achieve its stated goal of holding down weeds. To be fair it does do a reasonable job of this for the first year, maybe two. But after that period of time you have plenty of weed seeds established on top of the fabric and you will no longer notice any difference. Once those weeds start sprouting, the roots can get tangled in the fabric making them even harder to remove, causing an even more difficult weed situation than if you didn’t have the fabric in place at all.

Reason 2: It kills your soil. Like, kills it dead. Worms and other microorganisms are constantly hard at work in soil. They break down and incorporate organic matter into the soil, their tunnels aerate the soil and cause aggregates to form, which helps with water penetration into the soil. All of this activity is great for soil, which is great for plants. It can’t happen with weed fabric in place. The fabric prevents organic matter from getting into the soil, which makes it unlivable for those worms and beneficial microorganisms. Without that activity the soil becomes barren, compacted and dry. In other words: dead. The lack of natural nutrients forces the use of artificial fertilizers. The lack of aeration makes the ground compacted which forces roots to stay on the surface, making them less resilient to drought. The compacted soil becomes dry because water runs off the surface instead of penetrating the earth and allowing plants to take it up.

Reason 3: It kills your plants. The standard way to use weed fabric is to lay it down and cut holes where the trees, shrubs or flowers go. But, unless you go out every year and increase the size of the holes you cut, those plants could outgrow that hole fairly quickly. Trees stuck in a hole cut into weed fabric can become girdled and die as it outgrows these holes. Flowers can try to spread and end up spreading on top of the fabric instead of in the soil beneath making them less healthy while restricting their growth potential.

Weed barrier fabric was a fairly new product when the original part of the Conservation Garden Park was planted in 2001. Like everyone else, we had hoped that it would be a miracle weed reducer. We were wrong. Over the last 3 years have been removing it and it’s proven to be a real misery to “eradicate” so we can restore the soils in those areas to health.

Instead of weed barrier fabric, using a HEAVY coat of organic mulch 3-4” deep will accomplish the same thing while dramatically improving the health and quality of your soil. Top dressing with a light coat of mulch (1”) in subsequent years keeps the benefit in effect. As an added bonus, without the slick surface of weed barrier fabric beneath it, the mulch will grip in to the soil and be less likely to migrate or blow away.

To learn more, visit ConservationGardenPark.org or come and chat with our garden staff in person. 8275 South 1300 West, West Jordan, Utah.