Short answer
To stop grass spreading into beds, either cut a trench edge about 4 inches deep and 4 inches wide and re-cut it once or twice a year (University of Illinois Extension), or bury edging at least about 4 inches so runners hit a wall. Steel strip is the most durable buried edge, plastic is cheapest, and a flat brick or concrete mow strip lets you mow without trimming. Shallow no-dig borders hold mulch but do not stop grass roots.
Why grass crosses the line
Many lawn grasses spread sideways by runners, either underground (rhizomes) or along the surface (stolons). Any edge that only sits on top of the soil lets those runners pass straight underneath. That is why the depth of a lawn edge matters more than how it looks. Hunker notes that plastic edging in particular does not deter grass roots well, mostly because cheap strips sit too shallow or lift over time.
Spade edge vs buried edging
| Spade (trench) edge | Buried edging strip | |
|---|---|---|
| What it is | A V-shaped cut between lawn and bed, no material | A strip of steel, aluminum or plastic set in the soil |
| Depth | About 4 in deep and 4 in wide (Illinois Extension); 3 to 4 in (Hunker) | Usually about 4 to 6 in into the ground for metal (Edge Right, maker) |
| Cost | Free | About $1 to $11 per foot in material, by type (LawnStarter) |
| Upkeep | Re-cut once or twice a year (Illinois Extension), or every few months (Hunker) | Trim along it; fix heaved sections |
| Look | Natural, soft shadow line | Thin line or visible border |
A spade edge is the cheapest lawn border there is, and many gardeners prefer the soft look. Buried edging costs money and an afternoon, but it saves the yearly re-cut and holds mulch better. A good middle path: cut a spade edge this season, and add strip edging later along the beds where the grass keeps winning.
Lawn edging borders
-
01Most durable
Steel strip edging
Best for: long lawn edges where you want a thin line that lasts
- Height
- 4 to 8 in
- Shows
- About 1/2 to 1 in
- Stakes
- Bed side
- Illinois Extension calls steel the longest-lasting edging
- Can heave in frost unless staked well
- Full guide: metal landscape edging
-
02Budget
Plastic coil edging
Best for: big yards and curvy edges on a small budget
- Height
- Often 4 to 5 in
- Top
- Round bead is best
- Stakes
- Angled through the strip
- Illinois Extension prefers round-top styles to flat ones
- Lipped or grooved styles with steel stakes resist frost heave
- Full guide: plastic edging
-
03No trimming
Concrete mow strip
Best for: lawns where you want to mow right to the edge
- Form
- Poured or precast
- Cost
- $3 to $8 per ft poured
- Install
- Usually a pro
- A mower wheel rides along the top
- Permanent, and can crack
- Full guide: concrete curb edging
-
04Classic
Brick or paver mow strip
Best for: traditional gardens and DIY mow strips
- Laid
- Flat, level with lawn
- Base
- Sand or concrete
- Shows
- Flush
The concrete cost above comes from Lawn Love. For a full side by side of every material, see landscape edging materials compared.
Mow strips: the lowest-upkeep lawn edge
A mow strip is a flat band set level with the lawn surface. Because it is flush, one mower wheel rides on it and the blade cuts the grass right to the edge. That removes most string trimming along beds. Brick, pavers, flat stone and poured concrete all work. Illinois Extension recommends setting brick or stone on a sand or concrete base so it stays level. Poured concrete curbing is the continuous version; Lawn Love puts poured curbing at about $3 to $8 per linear foot.
How to cut a lawn edge by hand
Mark the line
Lay a hose along the edge you want and mark it with marking paint. Call 811 first if you will dig deeper than a few inches (Call 811).
Cut the lawn side straight down
Stand on the lawn and push a half-moon edger or flat spade straight down along the line, about 4 inches deep.
Angle the bed side
From the bed side, cut at an angle toward the bottom of the first cut so you lift out a V-shaped wedge of soil.
Clear the trench
Remove the wedge and any loose runners. Keep the trench open, or fill the bed side with mulch up to the cut.
Re-cut as needed
Touch up the edge once or twice a year, per Illinois Extension, or whenever grass starts to lean into the trench.
Lawn edging tools
Tools for lawn edges
A string trimmer turned on its side does a fair job of keeping a vertical edge, but it does not cut runners below the surface. Use it between the yearly re-cuts, not instead of them.
Next steps
Ready to bury edging? Follow how to install landscape edging and check how deep to set it. For the bed side of the line, see flower bed edging. Costs for a typical yard are in landscape edging cost.
Questions people ask
What is the best edging to stop grass spreading?
An edge that goes deep enough to block runners. Steel and aluminum strip edging, buried with only about 1/2 to 1 inch showing, works well and lasts. A concrete curb or a mortared mow strip also blocks grass. Shallow no-dig and loose stone borders do not stop roots well.
How deep should lawn edging be to stop grass?
University of Illinois Extension says a spade edge about 4 inches deep contains bluegrass, so buried edging should reach at least that deep. Most metal edging is set about 4 to 6 inches into the ground, according to maker Edge Right. Grasses with deep runners may need a taller strip.
How often should I re-cut a lawn edge?
For a spade-cut edge with no edging, University of Illinois Extension suggests touching it up once or twice a year. Hunker puts it at every year or every few months. Fast-growing lawns and wet seasons need it more often.
What is a mow strip?
A mow strip is a flat band of brick, pavers or concrete set level with the lawn along a bed. One mower wheel rides on it, so you can cut right to the edge without a string trimmer. Poured concrete curbing is a continuous version.
What tool do I use to edge a lawn?
A half-moon edger (a flat, curved blade on a long handle) cuts a clean manual edge. A string trimmer turned on its side, or a dedicated string trimmer edger, keeps the line tidy between cuts. Powered stick edgers with a steel blade are faster on long runs beside paths and drives.
Sources
- Hunker, The best types of landscape edging
- University of Illinois Extension, Bed edges (Rhonda Ferree, 2015)
- Edge Right, Types of landscape edging: why size and depth matter (maker)
- LawnStarter, How much does landscape edging cost? (updated December 27, 2025)
- Lawn Love, How much does landscape curbing cost? (updated October 2026)
- Call 811, Know what is below (national call-before-you-dig line)
Last reviewed October 12, 2026. Products, sizes and listings change; check the product details before you buy, call 811 before you dig, and follow the maker’s instructions.