Cutting Sod for a New 4-by-12 Perennial Bed With a Cutter Mattock: Edge Lines, a 1- to 2-Inch Slice, and Flipped Turf

Disclosure: This post contains affiliate links. If you purchase through these links, we may earn a small commission at no extra cost to you.

A 4-by-12 bed along a fence is 48 square feet of lawn to lift. That is small enough to do by hand in an afternoon, and a cutter mattock handles both the edge cuts and the slice under the roots.

How deep should you cut sod to start a new garden bed?

Slice just under the grass roots, about 1 inch deep and no more than 1 to 2 inches. Water two or three days before if the soil is dry, cut the outline first, then lift the sod in pieces small enough to carry. Keep the sod, because it holds valuable topsoil.

Iowa State University Extension's guide to killing grass for a new garden bed says to slide the blade horizontally just under the shallow root system, about 1 inch deep. It says to dig a couple of days after a soaking rain or water two or three days ahead.

The University of Maryland Extension's lawn removal methods page describes slicing the top 1 to 2 inches for areas under 100 square feet. It says to flip the sod beside the bed to dry and die, then mix it back into the soil once it turns completely brown.

Sod Job for a 4-by-12 Bed

Item	Figure
Bed area	48 sq ft
Slice depth	About 1 in., up to 2 in.
Sod volume at 1 in.	4 cu ft
Sod volume at 2 in.	8 cu ft
Compost to spread	2 to 4 in. per UMD
Pre-water	2 to 3 days ahead

At 1 inch, the sod lifted from 48 square feet fills only about two-thirds of a level 6-cubic-foot barrow. The thinner you slice, the less topsoil leaves the bed.

Using the Two Blades

The cutter blade chops a clean outline straight down through the turf. Short, controlled strokes keep the edge straight along a string line.

The adze blade then skims under the roots from the side. Hold it nearly flat and pull toward you in short strokes so it slices instead of digging.

Materials and Tools

• 5 lb cutter mattock with a 36-inch fiberglass handle
• Four stakes and a string line
• A garden fork for loosening the subsoil
• A tarp for stacking sod
• Finished compost for a 2- to 4-inch layer
• Safety glasses, gloves, and sturdy boots

Sod Cutting Steps

1. Test the soil. UMD says soil testing should be the first step when converting lawn.
2. Water ahead. Soak the area two or three days before if it has not rained.
3. Mark the bed. Stake the corners and run a string line.
4. Cut the outline. Chop straight down along the string with the cutter blade.
5. Cut a grid. Divide the bed into 12-inch squares so each piece is easy to lift.
6. Slice under. Skim the adze under each square about 1 inch deep.
7. Flip the sod. Lay pieces grass-side down beside the bed or on a tarp.
8. Loosen the base. Rock a fork into the subsoil without turning it over.
9. Add compost. Spread 2 to 4 inches, then mix in the dead sod once it browns.
10. Mulch. Cover the bed right away so weeds do not sprout.

Mistakes and Hazards

• Slicing too deep and hauling away the bed's best topsoil
• Working sopping-wet soil, which ISU says makes sod heavy and compacts the bed
• Lifting pieces too big to carry with a straight back
• Leaving the bed bare for weeks
• Swinging the cutter blade near your feet or a helper

If the new bed will hold daylilies, see lifting and splitting an overgrown daylily clump. For a framed bed instead, read filling a new 4-by-8 raised bed 12 inches deep.

If moles or gophers work the lawn next to the new bed, a buried wire floor stops them. The hardware cloth mesh size and gauge guide explains which mesh to use.

FAQ

Can I skip digging and just smother the grass?

Yes. ISU describes smothering with at least 8 inches of wood chips, settling to 6 to 8 inches, and checking after 2 to 4 weeks.

What about areas over 100 square feet?

UMD suggests renting a sod cutter for larger areas, then flipping the strips and leaving them in place.

Should I throw the sod away?

UMD says no. Sod holds topsoil and organic matter, so flip it, let it die, and mix it back in.