The Best Landscape Fabric for Killing Weeds
Using landscape fabric on a perennial planting bed on our flower farm.
February 17, 2024
I’ve been using landscape fabric for nearly a decade on my 1-acre flower farm and in my home gardens to keep weeds under control. There are various types of landscape fabrics available on the market and I am going to discuss the single best landscape fabric you should be buying for every reason and application. Not all landscape fabric is made equally, and I will discuss the differences between the options available and why the kind of fabric that I use is superior to others.
After reading this post, you’ll want to read Pros & Cons of Using Landscape Fabric to learn from all of the mistakes I’ve made.
What is landscape fabric?
First, let’s briefly discuss what landscape fabric actually is. Landscape fabric, sometimes referred to as “weed barrier,” is a material that is laid on top of the ground like a blanket and secured with landscape pins to keep it on the ground. It is usually sold in rolls and comes in different kinds of material (more on that below). Landscape fabric is used for a lot of reasons but it is mainly used to prevent weeds from growing in garden beds. It does a fantastic job of smothering any weeds, grass, or any plant material that is growing underneath it.
The biggest thing to understand about landscape fabric is that it does NOT all work the same. There actually is good and bad landscape fabric.
Related: Methods for Organic Weed Suppression
good landscape fabric vs bad landscape fabric
The less effective, or what I’m referring to as “bad” landscape fabric is the kind you find at garden centers. It is a thin, soft, black cloth and what most people think of when they hear the term landscape fabric — because it is, in fact, a synthetic fabric. However, this type of landscape fabric really makes a mess in my opinion, and isn’t suitable for high traffic areas. When left alone for years, it ends up breaking down and turning into a gross, claggy material underneath layers of mulch.
The more effective, “good” landscape fabric is sold as an agricultural landscape fabric and is a heavy duty woven plastic. It is made up of strands of plastic that are woven together, which makes the “fabric” water permeable and breathable. This landscape fabric is what I recommend you use in every application — for weeds, for your gravel driveway, to kill grass, to prep a planting area — simply because it is so effective and will last an incredibly long time if taken care of.
Here are the exact rolls of DeWitt/Sunbelt Landscape Fabric we use on our Farm and in our Home Gardens:
What is landscape fabric made of?
Landscape fabric is made of plastic. This means that landscape fabric is not a sustainable product — the production of landscape fabric uses fossil fuels and contributes to the atmospheric carbon load. Despite the use of fossil fuels in production, we continue to use landscape fabric on our farm because it is more sustainable for us, as farmers, to prevent weed growth by using landscape fabric rather than hand pulling (too much time and labor) or tilling our soil (too much soil destruction).
Good landscape fabric lasts a long time, though. We take care of our fabric supply and are still using Dewitt fabric that is 8+ years old. Since this brand of landscape fabric lasts so long, I feel okay using it in our sustainable farming operation because we’re able to reuse it over and over again for many years. This is not the case with other plastic mulches.
Related: How to Plant Clover Pathways
Is landscape fabric water permeable?
Yes, landscape fabric is entirely water permeable. Landscape fabric is made up of thin strands of plastic that are woven together and allow water and air through it. In heavy rain events, landscape fabric will drain water slower than usual, but it does not entirely stop water from draining.
Why isn’t landscape fabric draining?
If there are puddles of water on top of your landscape fabric, it is not because of the landscape fabric — it is because your soil is not draining properly. There is a common misconception that puddling water on top of landscape fabric means the fabric is holding all the water. This simply is not true, because landscape fabric is made of woven plastic threads and is designed to allow water to totally drain through to the soil below.
The water on top of your landscape fabric could be standing there for many reasons. Perhaps you have a high water table in early Spring or during a flooding event, or your soil is compacted clay and drains very slowly. Puddling water on top of landscape fabric is a helpful indicator of slow draining soils and that area may require interventions such as adding drain tile, digging drainage ditches or permanent raised beds, or simply broadforking the area and adding compost for a few years to help activate soil microbiology.
Related: The Reasons Why Miracle-Gro Is So Bad for Your Garden
how to hold down landscape fabric
When you lay landscape fabric, it’s incredibly important that you secure it into the ground using 6-inch landscape pins. I prefer these Sandbaggy landscape pins and pounding them into the ground works best using a rubber mallet. You’ll want to pin the fabric down every 2-4 feet depending on how exposed and windy your area is (closer pinning for windier sites).
Beware that landscape fabric, when left overwinter or exposed to windy conditions, will come right up out of the ground. You need to hold it down with heavy concrete blocks. Read our post on the Pros & Cons of Landscape Fabric to learn how to keep it in place.
When to remove landscape fabric
Landscape fabric, ideally, should be removed at the end of every growing season if you are using it in your annual garden. It can be rolled up and stored in a shed or garage (up away from mice — they will eat holes in it all winter). If you are using landscape fabric in a permanent landscape, it can be left permanently, but make sure it is secured down using heavy rocks or mulch on top so it doesn’t blow away in winter windstorms.
mulch on top of landscape fabric
You should only use mulch on top of landscape fabric if you are using it in a permanent planting bed. It’s important to understand that any soil or mulch that contains seeds that is placed on top of the landscape fabric will risk growing weeds on top of it. Also, squirrels and birds will bury and poop seeds on the mulch, which could then root on top of your landscape fabric. This is just something I think you should be aware of before deciding to put mulch on top of the fabric. The landscape fabric will do a fantastic job of suffocating all the weeds underneath it, but not any that are on top of it.
Does landscape fabric protect plants from a freeze?
Landscape fabric does not function to prevent plants from freezing. You’ll want to use frost cloth for that.
It’s important to understand the parts of the plants you need to protect from freezing. The top parts of annual plants — leaves, stems, flowers and fruits — are what you would want to protect in an overnight freeze. Landscape fabric is laid on the ground and does nothing to prevent any of those plant parts from freezing. It may protect the top layer of soil from freezing, but not during a deep freeze event — and honestly, if the top parts of the plants are frozen, protecting the roots doesn’t matter at that point. Perennial plants will always be okay in a freeze because their roots can withstand freezing temperatures.
To protect plants from a freeze, set up metal hoops using galvanized steel wire around your plants with frost cloth over them. The frost cloth will need to be secured to the ground with landscape pins, or heavy rocks, to prevent any cold air from creeping in overnight. You can also just throw an old bed sheet or blanket over your bigger plants in an effort to save them in a freeze.
Related: Our Favorite Resources for Vegetable Gardening: Books, Tools, etc
does landscape fabric kill grass?
Yes, if you place landscape fabric on top of a lawn it will kill whatever is underneath. To kill grass using landscape fabric, simply pin the fabric down on the grass you intend to kill and leave it for a few months. Sunny, hot months will take less time than cold, wet months.
Silage Tarps are actually quicker and more effective for killing grass than landscape fabric, though. You can read all about what silage tarps are, and how they work, here.
Why would you want to kill grass with landscape fabric? Well, this is a wonderful way to start a wildflower or meadow garden, or a new native planting area, or a new veggie garden, without tilling! I have a great tutorial post on Sheet Mulch Gardening that can help you with this fun endeavor.
List of Uses for Landscape Fabric
Kill and Prevent Weeds in Planting Beds
Use landscape fabric on perennial planting beds to keep weeds down, indefinitely
Use landscape fabric on annual planting beds and remove fabric at the end of each season
create a pathway through your yard or garden
Lay 3-ft wide landscape fabric directly on top of grass and cover with gravel, woodchips or mulch to create easy, weed-free pathways in your yard
use landscape fabric Underneath gravel in driveways
The Dewitt brand landscape fabric is a heavy-duty commercial grade landscape fabric that is perfect for laying on your driveway to prevent weeds from growing underneath gravel. If you are using rocks or gravel that have sharp edges, I would recommend laying two layers of the landscape fabric down, to prevent the rocks from poking holes in the fabric when you drive on it. The landscape fabric is water permeable, so two layers of it will not cause drainage issues.
Kill grass and smother weedy areas before planting
You can pin landscape fabric down on part of your lawn to kill anything growing underneath it (except invasive perennial weeds — those are nearly impossible to kill unless you fully dig out every piece of root). Silage tarps actually work better to kill grass and weeds in preparation for a new garden space, but you can absolutely use landscape fabric if you have it on hand.
line a drainage ditch or french drain in landscape fabric
You can line your french drain or drainage ditch with landscape fabric to keep it clean and weed-free.
Wrap drain tile in landscape fabric
If you are installing drain tile (perforated plastic piping installed in the ground to move excess water), you can wrap the pipe in landscape fabric to prevent the holes in the drain tile from becoming clogged with soil.
Line planters and raised beds with landscape fabric to prevent soil leakage
You can use landscape fabric as a liner for the bottom of pots, planters and the bottom and sides of raised garden beds to prevent soil from leaking out.
I hope this has helped you make a decision whether landscape fabric is right for your needs, and that you purchase the best landscape fabric there is.
