Why Sink Stones Into The Grass?

A path laid on top of a lawn looks handsome for a season and then becomes a nuisance. The mower scalpels the grass around every stone, the edges crumble, and within a year you have a trail of wobbling slabs surrounded by bald patches. The alternative is to set the stones slightly below the level of the grass, so the mower passes straight over them and the path reads as part of the lawn rather than an interruption to it.

This is sometimes called a flush or sunken stepping-stone path, and it is one of the oldest tricks in garden design. It guides the eye and the foot exactly where you want them without hard-edging, without gravel spilling into the borders, and without the expense of a full paved walk. Done properly, it will outlast most of the planting around it.

Choosing The Right Stone

Not every stone behaves well at ground level. The surface will hold damp for longer than a raised path, so traction matters more than appearance alone.

• Riven sandstone or Yorkstone — the classic choice. Naturally textured, warm in tone, and forgiving underfoot when wet.
• Granite or whinstone — hard, dense and effectively permanent. Ideal for heavy traffic and shady, mossy corners.
• Slate — beautiful in cool grey, but it splits thin and can be slippery. Choose a riven or flame-textured face rather than a sawn one.
• Cast concrete replicas — perfectly serviceable and uniform, though they rarely weather into the garden the way real stone does.

Avoid anything with a polished or sawn-smooth finish. Height of stone matters too: aim for 25mm to 40mm thick as a minimum. Thinner slabs crack the first time you wheel a barrow of compost across them, and the cost saving is rarely worth it.

For sizing, most people find stepping stones of 450mm to 600mm across comfortable. Set them as single slabs for a light, airy rhythm, or as pairs and clusters for a more generous landing outside a door.

Setting Out The Route

Before you cut anything, walk the route you actually take. Lay the stones loose on the grass and use them. Strangers to the garden will follow whatever line the stones suggest, so let the path curve gently rather than running dead straight — a straight run draws attention to itself.

Spacing is personal, but a stride of 600mm to 750mm between centres suits most adults. If children or older visitors use the garden regularly, close that up to around 500mm so nobody has to stretch. Keep at least 150mm of grass between neighbouring stones; less than that and the turf will struggle to knit back.

Check that the route clears anything the mower needs to reach, and that no stone sits within about 100mm of a wall or fence base, where you will want to use a strimmer rather than a blade.

Excavating And Bedding In

Cut around each slab with a half-moon edger or a sharp spade, then lift the turf in neat squares and set it aside on a tarpaulin. You will want it later.

Dig out to a depth of roughly 75mm to 100mm, depending on the thickness of the stone. On heavy clay, go deeper and fork the base to break up the pan so water can drain away.

Build up the layers:

• Sub-base — 50mm of compacted MOT Type 1 or a similar crushed stone, firmed with a plate compactor or the end of a sledgehammer. On soft ground, lay a geotextile membrane first to stop the sub-base sinking into the soil.
• Bedding — 25mm to 30mm of sharp sand, screeded level. Do not use builder's sand or soil; both shift and settle unevenly.
• The stone — bedded down with a rubber mallet, tapped until it sits firm and true.

Getting The Level Exactly Right

This is the part that decides whether the path works or haunts you every weekend. Lay a straight edge across the stone and onto the grass either side. The top of the stone should sit 10mm to 15mm below the crown of the surrounding turf — visible as a clean line, but low enough that a rotary mower passes over without clattering.

If you use a cylinder mower, be stricter still. A reel will catch anything proud of the surface, so check every stone individually rather than trusting a glance along the run. Stand on each one and rock your weight over it; any movement now means lifting and re-bedding before the grass fills in.

Once you are happy, backfill the joints with sieved soil, firm it gently, and replace the turves you lifted, trimming them to fit tight against the stone edges. Water the lot in well.

Aftercare And The Long Term

For the first few weeks, keep the new joints damp and stay off them as much as you reasonably can. Grass seed scattered into any bare gaps will close them within a fortnight in a growing season.

After that, maintenance is almost nothing. Mow as normal, raising the blade slightly for the first cut over new stones. Keep an eye out for moss and algae in shady spots — a stiff brush and a dry day is usually enough.

Every couple of years, lift any stone that has settled or become a trip hazard, top up the bedding sand, and reset it. Set into a proper base, a well-chosen stone path will outlast the fence, the shed and probably the mower. That is the quiet pleasure of doing one small piece of stonemasonry properly: it stops being a project and simply becomes part of the garden.