Line a raised garden bed with cardboard, landscape fabric, or hardware cloth, depending on whether you need weed control or pest protection—plastic generally shouldn’t be used.
Most gardeners don’t need a liner at all. The question of how to line a raised garden bed usually comes up for one of four reasons: you want to block weeds from below, stop burrowing pests, keep soil from washing out of the gaps, or protect your family from questionable wood treatments. Each goal calls for a different material, and picking wrong means ripping the bed apart later to fix it.
Here’s the practical breakdown of what to use, what to skip, and how to install it right the first time.
Do You Actually Need A Liner?
Skip the liner entirely if your bed sits on grass or soil and your only concern is drainage. Impermeable plastic at the bottom is the most common mistake—it traps water, soaks your soil, and rots roots over time.
A liner earns its place only when you have a specific problem to solve:
- Weeds and grass creeping up from below: cardboard or landscape fabric
- Chipmunks, voles, or gophers digging in: hardware cloth at the bottom
- Soil washing out through gaps in the frame: landscape fabric
- A bed made from pressure-treated lumber: a wood or fabric barrier between soil and frame
If none of those describe your situation, save the money and fill the bed directly over leveled ground.
Liner Materials: What Works, What Doesn’t
Match the material to the threat. The cheapest effective option is usually cardboard—it blocks weeds, breaks down over a season or two, and adds organic matter as it decomposes. Newspaper works the same way; lay it several sheets thick and overlap the edges so grass can’t find a seam.
Landscape fabric is the breathable upgrade. It blocks weeds and holds soil in place while letting water pass through, and it lasts for years instead of one season. The trade-off is that it won’t stop anything that digs, and you’ll need to cut it to fit the bed’s interior exactly.
Hardware cloth is the only material that stops burrowing pests. One key warning from garden builders: standard chicken wire is too coarse. Chipmunks can squeeze right through it—use hardware cloth with ¼-inch mesh or finer to actually exclude them. Note that the mesh can rust underground over time, especially in damp soil, so consider it a long-term but not permanent barrier.
Plastic deserves a hard warning. If you use it at all, it must be food-safe sheet plastic with drainage holes punched through the bottom, and even then it risks trapping water in heavy rain. For edible gardens, the safer call is to skip plastic entirely and use landscape fabric or cardboard instead.
How To Install A Liner Step By Step
Installation is the same regardless of material, with a few material-specific tweaks. Start by clearing the site completely: pull weeds, roots, rocks, and sod, then level the ground. A bed that sits on uneven dirt will shift, and gaps will let weeds and pests find their way in later.
Measure the bed’s interior and cut your material generously. For landscape fabric, leave plenty of extra to run several inches up the inside walls of the frame—this is what keeps soil from washing out through the corners. Lay the material flat with no folds or air pockets, overlapping pieces by several inches if your bed is large enough to need more than one sheet.
Secure the liner to the frame. Roofing nails work well for landscape fabric on wood frames; heavy-duty staples placed every 6 to 12 inches are the more common approach and hold just as well. If you’re using hardware cloth, staple or nail it flat across the bottom and up the lower walls so nothing can tunnel around the edges.
Once the liner is tight and secure, fill the bed with your soil and compost mix. The liner should sit completely flat against the bottom—if it’s loose or folded, the weight of the soil will shift it around and create pockets where the barrier stops working.
What About Pressure-Treated Wood Frames?
Pressure-treated lumber resists rot but raises a fair question about what’s leaching into your food. One common approach used by DIY builders is lining the interior of the frame with red cedar boards—cedar naturally resists moisture and decay, and it gives you a clean barrier between the treated wood and your soil. It’s more work and more cost than fabric, but it’s the most durable solution for a long-lived bed, particularly if you’re growing root vegetables.
If cedar isn’t in the budget, a heavy landscape fabric liner running up the inside walls achieves a similar separation for a fraction of the cost. Either way, the goal is the same: keep soil from sitting directly against treated lumber.
The material you need depends entirely on what you’re fighting. For weeds, cardboard or fabric. For diggers, fine hardware cloth. For treated frames, cedar or a fabric barrier. If you’re ready to buy, our roundup of tested garden bed liners compares the top options by durability, drainage, and pest resistance.
| Material | Best For | Key Caveat |
|---|---|---|
| Cardboard / newspaper | Weed and grass suppression | Breaks down after 1–2 seasons; needs replacement |
| Landscape fabric | Weed control and soil retention | Doesn’t stop burrowing pests |
| Hardware cloth (¼” mesh or finer) | Chipmunks, voles, gophers | Chicken wire won’t work; mesh rusts underground over time |
| Food-safe plastic with drainage holes | Moisture retention in specific situations | Risks trapping water; generally avoid for edible beds |
| Cedar boards | Lining pressure-treated frames | Most expensive and labor-intensive option |
FAQs
Should I put anything under my raised garden bed?
Only if you have a specific problem. Cardboard or landscape fabric blocks weeds, hardware cloth stops digging pests, and cedar or fabric protects against pressure-treated wood. If your bed sits on clean, level ground with no pest pressure, you can skip the liner entirely and avoid drainage issues.
Can I use plastic as a raised bed liner?
It’s not recommended. Impermeable plastic traps water and can drown your plants’ roots in heavy rain. If you insist on using it, choose food-safe sheet plastic and punch drainage holes through the bottom, but landscape fabric or cardboard is the safer choice for edible gardens.
Does chicken wire stop chipmunks from digging into raised beds?
No. Chipmunks can squeeze through chicken wire openings. Use hardware cloth with ¼-inch mesh or smaller, and secure it flat across the bottom and up the lower walls of the frame so pests can’t tunnel around the edges.
References & Sources
- The Grounds Guys. “What Should I Put Under My Raised Garden Beds?” Covers cardboard, landscape fabric, and drainage considerations for raised beds.