No Landscape Fabric Needed
At Deep Roots Project, we carefully research best practices using a wide range of trusted sources before making gardening recommendations. Our goal is to teach a method that makes food gardening not only successful, but also as easy and low-maintenance as possible—especially for busy people who want great results with less work. When it comes to placing raised beds on gravel, we’ve found that using landscape fabric creates more risks and hassles than benefits. That’s why we recommend skipping it entirely.
If you're installing a raised bed on gravel, skip the landscape fabric underneath the bed. It's not just unnecessary—it can actually create problems over time.
Soil leakage and weeds: Most gardeners worry that soil will leak into the gravel or that weeds will creep up from below. But research and experience show that weeds rarely grow up through 15 inches of compost. Instead, they arrive from windblown seeds landing on the surface. And gravel itself is a natural weed deterrent. So putting plastic fabric between your gravel and raised bed won’t stop weeds—it just creates more work later.
Drainage issues: Landscape fabric also traps moisture and can interfere with drainage. If it gets clogged or pressed against uneven gravel, water may build up instead of draining freely, leading to soggy roots. Worse, it blocks the natural exchange of air, microbes, and moisture between the soil and the earth below. Over time, that hurts soil health and the thriving underground ecosystem your plants depend on.
Microplastic and chemical contamination: Another downside? Landscape fabric eventually breaks down into microplastics. Polypropylene, the most common material in these fabrics, doesn’t biodegrade. As it ages, it sheds plastic fibers into the soil—polluting your garden for years to come. Some fabrics also leach chemical into the soil over time.
Fabric free ways to contain soil leakage
So what can you do if you’re worried about compost leaking into your decorative gravel? There are smart, fabric-free ways to contain soil:
Add coarse gravel pebbles: The best solution with the least work is to spread coarse gravel pebbles over your fine gravel extending about a foot around the bed. If soil leaks out of the bottom it will mix with the fine gravel and be hidden by the course gravel. Best choice is gray pebbles (also called pea gravel) with same gray color as your fine gravel.
Recess the bed slightly—dig a shallow trench (2–3 inches) into the gravel so the bed frame sits lower. This helps hold in compost at the base.
Line the bottom inside edge with cedar boards, bricks. These act as a gentle barrier without sealing off water flow.
Add a natural breathable liner like burlap or straw inside the base of the bed. These will decompose safely over time while filtering fine soil particles during the first rains.
Polypropylene releases microplastics in soil
The most significant environmental issue with landscape fabric is not acute toxicity and chemical leaching, but long-term microplastic pollution. Polypropylene doesn’t biodegrade; it only breaks into smaller pieces. A buried weed barrier will gradually degrade (from soil microbes, moisture, physical stress, and any UV at edges) and start shedding fibers and fragments. A recent scientific study using Raman spectroscopy confirmed that after 7 years in a garden, a polypropylene landscape fabric had released many microplastic fragments and fibers into the soil.
Once in the soil, these microplastics persist for a very long time. They can be carried by water or soil creatures, possibly reaching groundwater or being taken up by plant roots. Studies have shown that very small plastic particles can be absorbed by plant tissues and even end up in fruits, though research is ongoing. One environmental magazine warns that as fabric degrades, “microplastics will find their way to groundwater and into your plant’s circulatory system”, along with whatever chemicals are in those plastics. unsustainablemagazine.com
A Bonus Tip
And here’s a bonus tip: when you use 100% compost, as Deep Roots Project recommends, it holds together better than blended soils. Compost's rich microbial structure helps it settle firmly and resist leaking.
In short, landscape fabric under raised beds may seem like a good idea, but it causes more harm than good. Stick with natural solutions, and you’ll support healthy soil, clean pathways, and a garden that grows stronger every year.
Landscape fabric under raised beds causes more harm than good
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Beautify Your Garden with Our Cedar Raised Beds!
Our Deep Roots handcrafted cedar raised beds are designed to endure outdoors while adding a touch of style to your yard. As a bonus, they are the perfect depth to hold just the right amount of our nutrient-rich compost growing medium, which comes free with each bed.
Deep Roots Supports Gardeners
We provide our gardeners with the best products for success – like cedar raised beds, microbe-rich compost and microbe-rich worm castings. Check our online store. Always talk to our customer support team before placing your order online. If you need help or have a question contact us at support[at]deep-roots-project.org and 708-655-5299.
Deep Roots Online Store
See our online store for details about prices, ordering and delivery of raised beds, planter boxes, microbe-rich compost, worm castings, leaf mulch and more. We don’t sell traditional soil, since we use 100% compost as our growing medium. Our online store has 2 sections – (1) raised beds and planter boxes and (2) compost, worm castings, fertilizer.
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