If you’re looking to clear a weedy patch or install a new garden bed, you might be wondering, will landscape fabric kill grass? The short answer is yes, it can be an effective weed control solution when used correctly. This material, also called weed barrier cloth, works by blocking sunlight and smothering vegetation beneath it. But its success depends entirely on how you use it.
Let’s talk about what landscape fabric is and how it works. It’s a permeable textile, usually made from woven or non-woven polypropylene. It’s designed to let water and air seep through to the soil while blocking sunlight from reaching weed seeds and existing plants. Without light, plants can’t photosynthesize and will eventually die.
However, it’s not a magic bullet. Missteps in installation or choosing the wrong type can lead to frustration. This guide will walk you through the pros, cons, and the precise steps to use landscape fabric effectively so you get the results you want.
Will Landscape Fabric Kill Grass
Yes, landscape fabric can kill existing grass, but it’s a process that requires patience. Simply laying the fabric over tall, healthy grass is often ineffective. The grass may grow sideways, finding light at the edges, or even push up through the material if it’s not properly secured.
For the best results, you need to prepare the area first. This involves cutting the grass as short as possible. The fabric works by creating a physical, light-blocking barrier. When installed over short grass, it accelerates the smothering process by completely depriving the grass of its energy source.
Think of it like putting a blanket over a plant. The plant will use up its stored energy trying to grow, but without light, it will eventually exhaust itself and die. This method is a non-chemical approach to clearing land, which is a big advantage for organic gardeners or those with pets and children.
How Landscape Fabric Works for Weed Prevention
Beyond killing existing grass, the primary purpose of landscape fabric is long-term weed suppression. It acts as a barrier in new garden beds, under pathways, or beneath rock mulch. By blocking sunlight, it prevents new weed seeds in the soil from germinating.
The fabric’s permeability is key. Quality landscape fabric allows rainwater and oxygen to reach plant roots while keeping the soil surface dark. This is crucial because completely impermeable sheets, like plastic tarps, can create runoff and suffocate soil life.
It’s important to remember that landscape fabric is a suppressant, not a permanent eliminator. Weed seeds can still blow in on top of the fabric and settle in the mulch or gravel you place over it. Some persistent weeds may also eventually find a way through cuts or seams.
The Step-by-Step Process to Kill Grass with Fabric
To reliably kill grass using landscape fabric, follow these steps. Rushing through preparation is the most common reason for failure.
1. Mow and Clear the Area. Use your lawnmower on its lowest setting to cut the grass as short as you can. Remove any large debris, rocks, or sticks from the surface.
2. Water the Ground. Lightly moisten the soil. This helps the fabric settle and can speed up the decomposition of the grass underneath.
3. Lay the Fabric. Unroll the landscape fabric over the entire area. Overlap seams by at least 6-8 inches to prevent grass and weeds from finding a gap.
4. Secure Thoroughly. Use landscape fabric pins (often called garden staples) every 2-3 feet along the seams and edges. This is critical—wind can get under loose fabric and tear it.
5. Cover with Mulch. Apply a 2-3 inch layer of mulch, such as bark chips or gravel, on top of the fabric. This adds weight, blocks light completely, and protects the fabric from UV degradation.
6. Wait. Allow at least 4-6 weeks for the grass and weeds underneath to fully die. For tougher perennial weeds, it may take a full growing season.
Potential Drawbacks and Considerations
Landscape fabric isn’t perfect for every situation. Being aware of its limitations helps you decide if it’s the right tool for your job.
One major issue is soil health. Over many years, fabric can interfere with the natural exchange of organic matter. Fallen leaves and other debris can’t decompose into the soil, which can lead to poorer soil structure and less microbial activity underneath.
Another common problem is fabric degradation. Cheaper, non-woven fabrics can tear easily and may only last a season or two. Even quality fabric can become clogged with soil particles over time, reducing its permeability and creating runoff issues.
In planting beds, fabric can make it difficult to add new plants or divide existing ones. You have to cut holes in the fabric, which can become entry points for weeds. The roots of desirable plants can also sometimes become entangled in the material.
Where Landscape Fabric Shines
* Under permanent pathways with gravel or stone.
* In rock gardens with minimal planting.
* Underneath non-organic mulches in utility areas.
* For creating a clean base for patios or play areas.
Where You Might Avoid It
* In annual or vegetable gardens where soil is frequently turned.
* In rich perennial borders where plants spread and divide often.
* In areas with very healthy, loamy soil you wish to improve naturally.
Alternatives to Landscape Fabric
If the drawbacks give you pause, consider these effective alternatives for killing grass and suppressing weeds.
Cardboard and Newspaper: This is a fantastic, biodegradable method often called sheet mulching. Layer cardboard or thick stacks of newspaper directly over mowed grass. Wet it down, then cover with 3-4 inches of compost and mulch. It smothers grass, adds organic matter, and improves soil as it breaks down.
Thick Organic Mulch: Sometimes, a deep layer of mulch alone can do the trick. Applying 6-8 inches of wood chips or straw directly over short grass can smother it. The bottom layers will decompose while the top layers suppress weeds. You’ll need to top it up annually.
Solarization: This method uses clear plastic to trap the sun’s heat and “cook” grass and weed seeds. It’s most effective in hot, sunny climates. You stretch clear plastic over tilled, moist soil and seal the edges for 4-8 weeks during the hottest part of the year.
Manual Removal: For smaller areas, good old-fashioned digging with a spade or using a sod cutter is a immediate solution. It’s labor-intensive but provides a clean slate instantly without any barriers left in the soil.
FAQs About Landscape Fabric and Grass
How long does it take for landscape fabric to kill grass?
It typically takes 4 to 6 weeks to kill most grasses. Tough perennial weeds like Bermuda grass or bindweed may require a full season under the fabric to exhaust their root systems.
Can I just put landscape fabric over weeds?
You can, but for best results, cut them down first. Smothering tall, established weeds is harder because they have more energy stored. They are more likely to find a weak spot or grow laterally under the fabric.
What is the best landscape fabric to kill grass?
A heavy-duty, woven polypropylene fabric is generally the best choice. It’s more durable, less likely to tear, and provides excellent light blockage compared to flimsy non-woven felts.
Does water go through landscape fabric?
Yes, quality landscape fabric is designed to be permeable. It allows water and air to pass through to the soil while blocking light. However, cheap fabric or fabric clogged with soil can become less effective over time.
Will grass grow through landscape fabric?
If installed correctly over prepared ground, grass should not grow through it. However, if the fabric is thin, poorly secured, or installed over long grass, blades can potentially pierce through. Always use fabric pins and overlap seams generously.
Is it better to use plastic or landscape fabric to kill grass?
Plastic (like black plastic sheeting) is a more aggressive, non-permeable option. It will kill grass faster by creating a hotter, airless environment. However, it also completely kills soil biology and creates runoff. Landscape fabric is generally a better long-term choice for soil health.
In conclusion, landscape fabric can be an effective weed control solution for killing grass, but it’s not a simple “lay it and forget it” product. Its success hinges on proper site preparation and installation. For temporary grass removal or soil-focused gardens, biodegradable options like cardboard may serve you better. For permanent hardscape areas, a quality woven fabric is a reliable choice. By understanding how it works and its limitations, you can make an informed decision that saves you time and effort in your garden for years to come.