Can You Double Lanfscaping Fabric On Botyom Of Garden Boxes

Landscape fabric, weed barrier and weed barrier fabric are names for the same product. It is a black mesh type of plastic that is used extensively in landscaping to keep weeds out of your garden. Does it keep the weeds out? Does it let water through to the plants? Lets have a look at the effectiveness of landscape fabric.

landscape fabric - weed barrier

Landscape fabric – weed barrier cloth

Landscape Fabric – Weed Barrier Cloth

This is how landscape fabric is advertised to work. You place it on the ground and cover it with mulch. Weeds already in your soil can't grow through the cloth so they die. Weeds can't grow on the cloth, so any sprouting seeds also die. Voila! No weeds.

Don't Buy Into the Landscape Fabric Myth.

It is true that seeds sprouting under the cloth will not grow through it. However, strong perennial weeds will eventually grow through or around it. Many perennial weeds can grow quite a distance under ground and since landscape fabric comes in 3 and 4 foot wide roles they only need to grow a few feet to find an opening.

If you use a thin cover of mulch, weeds do not grow in the mulch because it is just too dry there. But in no time at all you will see the landscaping fabric stick up through the mulch and then it looks terrible in your garden.

If you use more mulch to hide the weed barrier, wind and water deposits soil particles and plant remains onto the cloth. In no time at all you have the perfect seed mix sitting right above the weed barrier, and weeds start to grow. Believe me when I say that plant roots can grow through the holes in the landscape fabric.

Weed barrier cloth is no better for controlling weeds than a 4 inch layer of mulch.

Landscape Fabric Stops Rain

Weed barrier cloth is porous (ie it has holes in it) and it is advertised as 'letting the rain flow through'. This is mostly a gardening myth. The reality is that some rain will go through the holes, but much of it flows over top of the cloth and away from your plants, which remain dry.

Garden Myths book by Robert Pavlis

Weed Barrier Sucks the Life out of Your Soil

I've talked many times about the importance of life in the soil. Landscape fabric reduces the air reaching the soil, and prevents any new organic matter from getting to the surface of the soil. It does not take long and the dew worms, microbes and other soil life, which depends on air and food, either leave or die. When this happens, there is a reduction of nutrients for your plants, and soil structure starts to degrade. Neither is good for your plants.

Permanent Plantings are Damaged

In permanent landscapes, plant roots will grow into and through the landscape fabric. At some point in the future when it is replaced (needs to be replaced every 10 years or so), you will damage the roots.

Is There a Good Use for Landscaping Fabric?

Maybe. If you are planting trees in uncultivated land that is very weedy, there is a benefit to using the weed barrier around the tree for a few years in order to keep the weeds down, and give the tree a chance to get established. The tree roots have less competition for space and nutrients. The loss of water due to the weed barrier is offset by the fact that the weeds are no longer using the water. The landscape fabric should be removed after a couple of years once the tree is large enough and strong enough to compete with the weeds.

Soil Science for Gardeners book by Robert Pavlis

Recent scientific findings, reported by Dr Linda Chalker-Scott, suggest that a 6- 12 inch layer of wood chip mulch is just as effective. I have used the landscape fabric, as described above, for trees planted in fields, but have now switched to using just mulch.

More Reasons for NOT Buying Landscape Fabric

it is a plastic and we don't need more plastic in the environment
plant roots growing on top of the fabric can't withstand a drought as easily
moving plants, and dividing plants is a nightmare because the weed barrier prevents you from digging new holes
if you do get weeds they are near impossible to pull out
it is relatively expensive for a product that does almost nothing!

References:

1) Photo Source: Two Women and a Hoe