Does Landscape Fabric Kill Weeds?

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Landscape fabric, which is also sometimes known as weed fabric, is a thin layer that is made from materials that allow air and moisture to penetrate the soil beneath while preventing sunlight from entering. It also blocks the growth of most weeds.

It is generally considered a short-term solution that works best on perennial beds, since the fabric is able to last at least five years before it needs to be replaced. You’ll need to pull up all the weeds you can before installing the fabric, and you will only have to do some basic light weeding once the fabric is in place.

Landscape fabric works great on its own, but it usually helps to cover it with decorative rocks, mulch, or other ground covers. The fabric separates the soil from the cover material, which keeps gravel and stone clean while also slowing down the breakdown of organic mulch, which is inevitable.

Black plastic, which is another kind of weed-blocking barrier, does something similar, but the plastic can tear easily. It also prevents air and water from reaching the plants that need it. But does landscape fabric kill weeds? Let’s take a look.

Catching Weeds Early

When you remove the weeds that would otherwise be covered with the landscape fabric, especially early on, the fabric will be able to halt the growth of mature weeds, while simultaneously allowing the desired plants to grow. If you don’t pull the weeds, they can and will grow through the fabric over time, particularly if it is an open mesh or if it’s thin.

When you pull up the weeds, make sure you take out both the entire root system and the upper stem. Most weeds are able to grow again from the roots that remain in the ground, so they will then grow through the fabric after it’s been laid down.

Getting Deep

You might have to do some more thorough weeding if your garden is particularly full of weeds or if it houses an especially stubborn weed, such as nutsedge. Nutsedge grows in hardiness zones of 8, 9, and 10, as defined by the US Department of Agriculture.

You could avoid this problem by trilling your soil before you install the landscape fabric. This will unearth any covered weed tubers and seeds, which you can then remove.

Tubers and seeds are able to sprout and grow underneath the fabric, after which they will inevitably tear through. If you let the soil dry before you install the plastic, the tubers of weeds that thrive on moisture will be dried out.

You could also cover the area with clear plastic for a month during the warmest and sunniest days of the year so that the roots and seeds are killed by heat after being unearthed via trilling.

Regular Maintenance

If you spot weeds that have started to grow through the fabric once you’ve laid it down, you will need to uproot them promptly so that they do not do any further damage to the strength of the fabric. Be sure to pull the weeds while they’re still young so that they are prevented from creating larger holes in the fabric.

It is also much easier to remove the whole root system of young weeds, as they are not as deep and expansive as mature weeds. If there’s a hole left behind after you’ve removed the weed, simply lay another, smaller piece of landscape fabric on top of it to patch it up. This can be anchored down using a U-shaped landscape stake.

You are likely to notice weed growth around and inside the base of plants instead of through the fabric. Make sure that you regularly check the soil around the base of the plants, as well as beneath the fabric edges around the planting hole, and pull any sprouting weeds the moment you find them so that they do not become established.

Best Weed Barrier

Top To Bottom

Inorganic or organic mulch will usually be thinly spread over the top of the fabric. It helps improve the overall look of the landscape fabric, while also preventing damage.

Organic mulch decomposes over time, and you’ll start to notice decaying plant material and soil accumulating at the top of the fabric underneath the layer of mulch. Weeds are able to germinate inside this layer of compost and soil, and while they do start out with shallow roots, the roots eventually begin to grow through the fabric, weakening it and also causing more weeds to grow beneath it.

Make sure that you uproot any weeds that germinate on top of the fabric as soon as you notice them. Also, try to avoid tearing holes into the fabric, unless you want to plant in that hole immediately afterward. If not, you risk allowing weeds to invade the bare soil.

General Tips For Landscape Fabric

Areas that have been covered with landscape fabric are going to need some maintenance to ensure that no weeds develop over time. Dust and soil that blows onto the fabric can build up and eventually support weed growth.

When the fabric becomes smothered in debris and soil, you will have to remove the ground cover and clean it or replace it entirely. If you decide to cover the landscape fabric with stones and other ground covers, keep in mind that you are able to rake them off and hose them down to remove any dirt that has accumulated.

Organic mulches need to be replaced. Because of this, it wouldn’t make sense to place a thick organic mulch layer over the fabric, since all mulch eventually becomes soil.

Thicker layers simply mean that there will be more soil, which means that there’s a higher risk of weeds forming and growing through the fabric. Even though landscape fabric is permeable, it will probably restrict the amount of moisture from spray irrigation or rainfall from reaching the soil beneath it.

When you plant inside the fabric, make sure to monitor your plants and ensure that they get enough water.

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