Cardboard vs Landscape Fabric for Weed Control: Pick by Job

Use cardboard for anything you plan to plant, and landscape fabric for ground you'll cover with stone and rarely touch again. That split covers most yards. The exceptions are weeds that spread by roots, and neither material handles those alone.

How does each material block weeds?

Both starve weeds of light, but cardboard smothers them and then rots away, while landscape fabric stays put as a permanent barrier.

Cardboard is the base layer of sheet mulching. Lay it over grass or weeds, soak it, and bury it under 3 to 4 inches of wood chips or compost. The plants beneath run out of light and die back. Over the season the cardboard softens, and worms and soil microbes work it into the ground as organic matter.

Landscape fabric is a woven or nonwoven sheet that passes water and air while blocking light. It stops weed seeds already in the soil from sprouting. It does nothing about seeds that blow in or drop onto the mulch above, and those seedlings root in the mulch and can grow down through the fabric. So fabric stops weeds from below, for a few years. From above, it doesn't. A bed that looks clean in year one can be a mess within a few years.

Cardboard vs landscape fabric: cost, lifespan and water flow

Cardboard is the cheaper option, often free, while landscape fabric costs a little more up front but can last years longer under stone.

What does it cost for a 4x8 bed and a 30-foot path?

The barrier is the small expense for either material: about $0 to $8 for a 4x8 bed in cardboard and $6 to $19 in fabric, with the mulch on top costing more than both. These figures assume a 32 square foot bed and a 30-foot path 3 feet wide (90 square feet), at typical U.S. prices that vary by region.

Bagged mulch costs noticeably more per cubic foot than bulk delivery, and delivery fees vary. Fabric price climbs with weight and weave. Budget a few dollars more for landscape staples.

Where does cardboard win?

Cardboard wins in any bed you will plant, amend or rework, including vegetable gardens, no-dig beds and new perennial borders.

It costs almost nothing, you can cut a hole through it for a transplant, and it disappears into the soil so nothing needs digging out later. In a vegetable plot, cardboard mulch for weeds is the clear pick. Roots push through the softened sheet by midseason, and you can top-dress with compost every year without defeating the barrier.

Expect a sheet to last roughly 6 to 12 months. A double layer in a dry climate can hang around longer; a single layer in a warm, rainy region may be gone in a few months. Top up the mulch each year and lay a new sheet only if weeds return.

1. Mow or cut existing weeds as low as you can. No need to pull them.
2. Use plain brown corrugated cardboard and strip off tape, staples and shiny labels.
3. Overlap every seam by at least 6 inches so no light gets through.
4. Soak it thoroughly with a hose.
5. Cover with 3 to 4 inches of wood chips or compost right away, before wind lifts it.

Where does landscape fabric win?

Landscape fabric wins under pea gravel, crushed stone and other rock mulch in places you won't replant, such as side-yard paths, utility strips and the area around a patio.

In those spots it also keeps stone from sinking into soft or clay soil, which cardboard can't do for more than a season. Overlap seams 6 to 12 inches, and pin it every 12 to 18 inches along edges with landscape staples. Choose a woven or heavier nonwoven product over the thinnest roll on the shelf, because thin sheets tear when you rake the stone.

Fabric is also reasonable under rock-covered shrub beds where the plants are permanent. Once you want to add a plant, divide a perennial or spread compost, you start fighting it. Weeds that seed into the rock still need pulling, too.

What does each do against bindweed and Bermuda grass?

Neither material reliably stops bindweed or Bermuda grass, because both spread by roots and runners that can survive a season in the dark.

Fabric is the weaker choice. Shoots find the seams, staple holes and planting holes, and Bermuda grass can send stolons across the top of the fabric and root into the mulch. Cardboard does better when you use two layers, overlap seams by 6 to 12 inches, and pile on 4 to 6 inches of mulch. Leave it for a full growing season and pull any shoots that poke through the moment you see them. Large root systems may mean repeating the process.

Nutsedge is the worst case. Its tubers can push through both materials, so don't count on a barrier to beat it. For persistent perennial weeds, your local Cooperative Extension office can tell you what works in your climate and soil.

Which is easier to plant through?

Cardboard is easier to plant through than fabric, and that is the biggest day-to-day difference between them.

With cardboard you cut an X or a hole, set the plant, and move on. With fabric you cut a hole for every plant, and each hole is a gap where weeds come up. Using landscape fabric in vegetable garden beds is the worst case: you replant every year, tomato and squash roots tangle in it, and torn fragments end up in the soil for good. We'd skip it there entirely.

Compost on top is the other trap. Spread it over fabric and weed seeds root in it within weeks. Over cardboard, compost simply becomes the next layer of soil.

With drip irrigation, lay the lines on top of the barrier and under the mulch, then check the emitters after you mulch. Keep mulch a few inches away from house siding, wood foundations and tree trunks, since damp mulch against them invites rot and pests.

Which should you choose for your situation?

Choose cardboard for beds, raised beds and no-dig gardens, and landscape fabric only for stone-covered paths and permanent rock beds.

Start collecting plain cardboard now. In much of the country, a bed laid in fall will be soft by spring and ready to plant.