The short answer
Most UK garden installations use a kiln-dried sand infill brushed into the pile after laying. The sand weighs the grass down so it lies flat and resists creasing, protects the backing and stitching, helps the fibres stand upright, improves drainage and adds a degree of fire resistance. No-infill (or non-infill) grasses are designed with a dense, stable construction that holds its shape without sand, which suits balconies, roof terraces and surfaces where added weight is a problem, or where a softer barefoot feel is wanted. For a typical ground-level lawn, sand infill is the standard and usually recommended approach because it improves stability and longevity. Choose no-infill only where weight, the substrate or a specific product designed for it makes sense.
Infill is one of the more confusing parts of buying artificial grass. Here is what the sand does, when you can skip it, and how each route affects how the lawn performs over time.
Infill vs no infill
- Standard for gardensSand infill
- Infill materialKiln-dried silica sand
- No-infill suitsBalconies, roof terraces
- Sand benefitsStability, drainage, fire
- PetsSand fine; rinse regularly
What sand infill does
After artificial grass is laid, a kiln-dried silica sand is usually brushed evenly into the pile. It is dry, fine and free-flowing, and it settles to the base of the fibres rather than sitting on top. Its job is structural: the weight holds the grass flat against the base so it cannot crease, ruck or lift at the edges, and it ballasts the grass without the need to glue or pin the whole surface.
The sand also protects the grass and helps it perform. It supports the fibres so they stand more upright, shields the latex backing and stitching from UV and wear, aids drainage by keeping the base of the pile open, and adds a measure of fire resistance by raising the burning point at the surface. A typical lawn is given several kilograms of sand per square metre, brushed in until it disappears below the fibre tips.
| Factor | Sand infill | No infill |
|---|---|---|
| Stability | Weighted, lies flat | Relies on dense construction |
| Fibre support | Helps fibres stand | Self-supporting design |
| Drainage | Improved | Depends on backing |
| Fire resistance | Improved | Lower |
| Weight added | Yes, several kg/m2 | Minimal |
| Best for | Ground-level lawns | Balconies, roof terraces |
Indicative comparison; follow the manufacturer's infill guidance.
When no-infill makes sense
Some grasses are engineered to be stable without sand, using a dense, low pile and a strong backing that holds shape on its own. These non-infill products come into their own where the weight of sand is a problem — balconies and roof terraces with load limits — or where the grass is laid on a hard surface like concrete or decking and adding sand is impractical. They can also feel softer and more barefoot-friendly because there is no firm sand bed beneath.
The trade-off is that, on the ground, a sand-filled installation is generally more stable and longer-lasting, and many manufacturers specify infill to validate their guarantee. So no-infill is a deliberate choice for a specific situation, not a shortcut to skip a step on a normal garden lawn.
Pets, feel and maintenance
For households with dogs, kiln-dried sand infill is generally fine and even helpful, because it supports drainage and the upright fibres. Regular rinsing keeps it hygienic, and some owners add a specialist antimicrobial infill alongside or instead of plain sand to manage odour. The key for pets is good drainage and routine cleaning rather than the presence or absence of sand itself.
On feel, a sand-filled lawn is firmer and more lawn-like underfoot, while a no-infill grass can feel softer and springier. On maintenance, sand-filled grass occasionally needs the sand topped up and brushed if it migrates over years, whereas no-infill grass simply needs brushing to keep the pile standing. Both need leaves cleared and the surface rinsed; neither is maintenance-free.
How infill is applied and kept topped up
Applying sand infill is one of the final steps of a garden installation, done once the grass is laid, joined and trimmed. The kiln-dried sand is spread evenly across the surface, usually a portion of a bag per square metre, and then worked down into the pile with a stiff brush or a powered brush, repeatedly, until it settles at the base of the fibres and is no longer visible from above. Doing this on a dry day matters, because kiln-dried sand flows freely when dry but clumps and refuses to brush in if it is damp. The aim is an even bed of sand throughout the pile, not patches, so the weighting and support are consistent across the whole lawn.
Over the years, a small amount of sand can migrate or settle, particularly in heavily used areas or where surface water runs across the lawn. Topping up is straightforward — more kiln-dried sand brushed in where the pile feels soft or the grass seems to lift — and is part of the occasional upkeep of a sand-filled lawn. A no-infill grass avoids this step entirely, which is one of its attractions for hard surfaces and balconies, but on the ground the trade-off is the reduced ballast and support that sand provides.
If you are unsure which route a particular grass needs, the manufacturer's specification is the authority. Many garden grasses state a recommended infill rate that forms part of the correct installation and any guarantee, while grasses sold specifically as non-infill are built to perform without it. Following that guidance, rather than assuming, is the safest approach: skipping recommended infill can leave a lawn prone to creasing and movement, while forcing sand into a non-infill product designed without it serves no purpose.
To summarise the decision: for a normal ground-level garden lawn, kiln-dried sand infill is the standard and usually recommended route, because it weights the grass flat, supports the fibres, aids drainage and adds a measure of fire resistance, all of which help the lawn perform and last. No-infill is a deliberate choice for specific situations — balconies and roof terraces with weight limits, hard surfaces where sand cannot be used, and products engineered to hold their shape without it — rather than a shortcut to skip a step on an ordinary lawn. Choosing between them comes down to the substrate, the weight you can add and the specification of the grass itself, so read the product guidance and match the infill approach to the surface you are laying on.
Frequently asked questions
Do you have to put sand on artificial grass?
Not always, but for a normal ground-level lawn it is the standard and usually recommended approach. Kiln-dried sand weights the grass down, supports the fibres, aids drainage and adds fire resistance. Some grasses are designed as non-infill and hold shape without sand, but for most gardens infill is specified.
What kind of sand goes in artificial grass?
Kiln-dried silica sand is used. It is dry, fine and free-flowing so it brushes down to the base of the pile rather than clumping. Builders' sand or play sand is not suitable because it holds moisture and does not flow into the fibres properly.
Is no-infill artificial grass better for balconies?
Often yes. No-infill grass avoids adding the weight of several kilograms of sand per square metre, which matters where a balcony or roof terrace has a load limit. It also avoids sand washing out through drainage gaps. For ground-level lawns, though, sand infill is generally the more stable choice.
Sources & further reading
Figures on this page are typical UK ranges drawn from published cost guides and are intended as guidance, not a quotation.