The short answer
To lay artificial grass on soil you remove the existing turf and excavate a few centimetres, then build a stable, free-draining base. The usual UK build-up is a layer of Type 1 MOT sub-base compacted with a plate compactor (wacker plate), topped with a thin sharp sand or grano dust layer screeded level to take out bumps. A weed membrane goes down to suppress growth — often one layer over the soil and one above the aggregate. The grass is then rolled out, left to settle and acclimatise, trimmed to fit, joined at any seams, and secured around the edges with galvanised pins or a timber/edging perimeter. Finally a kiln-dried sand infill is brushed in. Getting the base flat, firm and free-draining is the part that determines whether the finished lawn looks and performs well.
Laying artificial grass on soil is mostly groundwork. The grass itself goes down in an afternoon, but the digging, basing and compacting beneath it is what makes the difference between a lawn that stays flat and one that ripples, sinks or puddles.
Laying on soil at a glance
- First jobRemove turf, excavate
- Sub-baseType 1 MOT, compacted
- Levelling layerSharp sand or grano dust
- Weed controlMembrane layer(s)
- FinishPins/edging + sand infill
Preparing the ground
The first stage is clearing and excavating:
- Remove the existing turf and topsoil to a depth that leaves room for the new base plus the grass — commonly around 50–75mm, though it depends on the base depth you plan and the finished level you want against paths and patios.
- Mark out edges and set the finished level so the lawn sits just below adjoining hard surfaces, allowing for the grass thickness.
- Set a slight fall away from the house for drainage where possible — a gentle slope helps surface water run off rather than pool.
- On heavy clay or poorly draining ground, dig a little deeper and use a more generous free-draining sub-base, as drainage is the most common cause of problems on soil.
Excavated turf and soil will need disposing of, so plan for a skip or bags if the area is large.
Building the base
A good base is the heart of the job. The standard UK build-up over soil is:
- Weed membrane on the soil: a geotextile membrane laid over the excavated ground suppresses weeds coming up from below.
- Type 1 MOT sub-base: spread crushed stone in layers and compact each with a plate compactor (wacker plate), ideally dampening it so it binds. This creates a firm, free-draining foundation that won't sink.
- Levelling layer: a thin layer of sharp sand or granite (grano) dust, screeded and compacted to a smooth, level surface that takes out any remaining bumps and gives the grass a flat bed.
- Second weed membrane: many installers add a membrane over the levelling layer too, for extra weed protection beneath the grass.
Compaction is what stops the lawn rippling and sinking, so take time over it. The finished base should feel firm underfoot and look flat, with no soft spots.
| Layer (top to bottom) | Material | Purpose |
|---|---|---|
| Grass | Artificial turf + sand infill | The lawn surface |
| Upper membrane | Weed membrane | Suppress weeds under grass |
| Levelling layer | Sharp sand / grano dust | Smooth, flat bed |
| Sub-base | Type 1 MOT, compacted | Firm, free-draining foundation |
| Lower membrane | Weed membrane | Suppress weeds from soil |
Indicative typical build-up on a soil lawn. Depths vary by site.
Laying, fixing and finishing the grass
With the base ready, the grass goes down:
- Roll out and acclimatise: lay the grass loosely and leave it for a few hours (longer in cold weather) so it relaxes flat and any creases settle. Keep all pieces running in the same pile direction.
- Trim to fit: cut the grass to the edges from the back with a sharp blade, working slowly for a neat line.
- Join seams: where two pieces meet, butt the rows of stitches together and bond them with jointing tape and adhesive, keeping fibres out of the glue.
- Secure the edges: fix the perimeter with galvanised U-pins or ground pins, or fasten to a timber/composite edging board, so the grass cannot lift or move.
- Brush in sand infill: spread kiln-dried sand and work it into the pile with a stiff brush. This weighs the grass down, supports the blades and keeps it flat.
A final brush against the pile lifts the fibres and gives the lawn a full, even finish. Done carefully, a soil installation should look natural and stay flat for years.
Tools, timing and common mistakes
Knowing what the job needs and where people go wrong makes a soil installation far more likely to succeed first time.
Tools and materials for a typical soil lawn include: a spade and rake or a turf cutter for excavation, a plate compactor (wacker plate) which can be hired by the day, a wheelbarrow, a screeding board and spirit level, a sharp utility knife with spare blades, a stiff broom, galvanised pins or edging, jointing tape and grass adhesive, and the aggregates — Type 1 MOT, sharp sand or grano dust, weed membrane and kiln-dried sand infill. The compactor is the one piece most people don't own and is worth hiring rather than skipping.
Timing and conditions: the work is easier in dry weather, since wet soil is heavy to dig and aggregate compacts better when lightly dampened rather than waterlogged. Grass also relaxes and lies flat more readily when it is warm, so cold days mean allowing longer for it to acclimatise. Adhesive at seams cures more slowly in cold, damp conditions.
The most common mistakes on soil are worth flagging:
- Under-compacting the base — the leading cause of a lawn that later dips and ripples. Compact each layer properly.
- Skipping the weed membrane — invites weeds up through the lawn and seams.
- An uneven levelling layer — every bump and hollow telegraphs through the grass, so screed it carefully.
- Mismatched pile direction between pieces — produces a patchwork that no amount of brushing fixes.
- Stretching the grass while pinning — it should lie relaxed; over-tensioned grass can pull and pucker.
Allow enough time, get the base flat and firm, and the grass-laying itself is the quick part. A soil installation done patiently looks natural and stays flat for many years, which is why the groundwork is where the effort belongs.
Frequently asked questions
Can you lay artificial grass straight onto soil without a base?
It is not recommended. Laying grass directly on soil tends to lead to an uneven, lumpy surface, poor drainage, weeds pushing through, and the grass sinking or rippling over time. A compacted Type 1 sub-base with a sharp sand levelling layer and weed membrane gives a flat, firm, free-draining result that lasts. The groundwork is what makes the lawn perform.
What depth do you need to dig out for artificial grass on soil?
It varies with the base you plan, but excavating around 50–75mm is common for a domestic lawn, allowing for the sub-base, levelling layer and grass thickness while keeping the finished level just below paths and patios. On heavy clay you may dig deeper to fit a more generous free-draining sub-base for better drainage.
Do you need weed membrane under artificial grass on soil?
Yes, weed membrane is strongly advised on soil. A geotextile membrane over the soil suppresses weeds growing up from below, and many installers add a second membrane above the levelling layer for extra protection. The membrane still lets water drain through while stopping most weed growth beneath the lawn.
Sources & further reading
Figures on this page are typical UK ranges drawn from published cost guides and are intended as guidance, not a quotation.