Should you put landscape fabric under a raised bed?

Generally no. Lining the bottom with landscape fabric blocks the very thing that makes a ground-level raised bed work — roots growing down into the soil below for extra depth, water and nutrients — and over time fabric can also impede drainage and clog with fine roots and soil. For weed control before filling, plain cardboard laid on the ground smothers grass and then breaks down, letting roots through afterward. Save landscape fabric for paths and the inside faces of wooden walls, not the bed floor.

What should you put on the bottom of a raised bed on soil?

For a bed on open soil, the best bottom is usually nothing that blocks roots. Loosen the ground with a fork so roots can penetrate, then lay plain cardboard directly on the grass to smother it — it kills the lawn and decomposes within a season, after which roots pass freely into the earth. If burrowing rodents like voles or gophers are a problem, add hardware cloth (galvanized wire mesh) at the bottom, which stops animals while still letting roots and water through.

Does landscape fabric stop weeds in a raised bed?

It reduces weeds from below at first, but it is not a lasting solution and brings trade-offs. Over time, windblown weed seed lands and sprouts in the bed's own soil regardless of any liner, and roots and fines can clog the fabric so it impedes drainage. Cardboard smothers existing grass more cheaply and then disappears. For the bed floor, the weed benefit of landscape fabric rarely outweighs the harm to rooting and drainage; keep fabric for pathways around the beds instead.

Should you line the inside walls of a wooden raised bed?

Lining the inside faces of a wooden bed is worthwhile — it slows the wood from rotting by keeping wet soil off it, extending the bed's life. Use a heavy plastic or a pond-liner-grade material on the side walls only, and do not line the bottom, so drainage and rooting are preserved. Staple it above the soil line. This is the one place lining clearly helps: it protects the wood without the downsides that a bottom liner creates.

Is it OK to use cardboard in the bottom of a raised bed?

Yes, plain cardboard is a widely used and effective bottom layer for a bed on soil. Laid over grass, it smothers the lawn and weeds by blocking light, then decomposes within a season or so, after which plant roots grow straight through into the ground below. Remove any tape and heavy glossy print, and overlap the sheets so grass cannot find gaps. It is cheaper than landscape fabric, does the weed-smothering job better for this purpose, and does not permanently block roots.

Should You Line a Raised Bed With Landscape Fabric?

Written & researched by Elena Marsh Gardening & Landscaping Editor

Updated October 2026

Wide view of a person's hands pressing seedlings into dark soil in a timber raised bed, in soft early-morning light

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Usually not on the bottom. Lining the floor of a ground-level raised bed with landscape fabric blocks what makes it work — roots growing down into the soil below for extra depth, water and nutrients — and over time the fabric can impede drainage and clog with roots and fines. For weeds, plain cardboard smothers grass and then breaks down, letting roots through afterward; against burrowing rodents, use hardware cloth, which stops animals but not roots. Where lining does help is the inside faces of a wooden bed's walls, to slow the wood from rotting. Match the material to the job.

Why not line the bottom?

A ground-level raised bed's biggest advantage is that it is open to the earth beneath it. Roots that reach the bottom of the frame keep going into the native soil, drawing water and nutrients and giving plants a far larger effective root zone than the frame's depth suggests — a 12-inch bed can behave like a 24-inch one. A landscape-fabric floor throws that away by separating the bed from the ground. Worse, over a few seasons fabric tends to clog with fine roots and settled soil, so it starts impeding drainage exactly where you least want a barrier. The weed benefit it offers below is modest and temporary, since windblown seed sprouts in the bed's own soil regardless. For the bed floor, the costs outweigh the benefit.

Golden-hour view of a person's hands pressing seedlings into dark soil in a timber raised bed

What to put on the bottom instead

Match the material to what you are actually trying to solve.

Goal	Best material	Why
Smother existing grass/weeds	Plain cardboard	Blocks light, then decomposes; roots pass through after
Stop burrowing rodents (voles, gophers)	Hardware cloth (wire mesh)	Blocks animals but lets roots and water through
Protect wooden walls from rot	Plastic / pond liner on sides only	Keeps wet soil off the wood, extends bed life
Preserve rooting and drainage	Nothing / loosened soil	Open bottom is the whole point on soil

Overhead view of a person's hands pressing seedlings into dark soil in a timber raised bed, in soft early-morning light

Cardboard for weeds, hardware cloth for critters

Two cheap materials cover the real problems a bottom liner is meant to solve, without blocking roots. Plain cardboard laid over the grass before filling smothers the lawn by cutting off light, then rots away within a season — after which roots grow straight down into the earth. Remove tape and heavy glossy print, and overlap the sheets so grass cannot sneak through gaps. If burrowing rodents are a genuine problem in your area, staple galvanized hardware cloth across the bottom of the frame before filling; the wire mesh stops voles and gophers coming up from below while letting roots and water pass. Cardboard and hardware cloth can be combined — cardboard on top of the mesh — to handle weeds and critters at once.

Wide view of a person's hands pressing seedlings into dark soil in a timber raised bed, in bright midday sun

The one place lining helps: wooden walls

Lining is genuinely useful in one spot — the inside faces of a wooden bed's walls. Constant contact with wet soil is what rots wood, so a barrier of heavy plastic or pond-liner-grade material stapled to the side walls (above the soil line, sides only) keeps moisture off the boards and can add years to the bed's life. Crucially, this leaves the bottom open, so drainage and rooting are untouched. It is the inverse of the common mistake: line the sides to protect the wood, leave the bottom bare to protect the plants. Metal beds do not need this, and beds on hard surfaces are a separate case with their own drainage rules.

The bottom line

Skip landscape fabric on the bottom of a soil-based bed — use cardboard to smother grass, hardware cloth against burrowers, and wall liner only to protect wooden sides. Keep landscape fabric for the paths around your beds instead. What actually goes inside matters more than what lines it — see what to fill a raised bed with and how deep it should be. For a bed on a hard surface where the bottom rules differ, see raised bed on concrete.

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