How To Prep For Artificial Grass In 7 Simple Steps
A high-quality artificial lawn starts with what sits underneath it.
Artificial grass can hide the soil from view, but it cannot disguise an unstable base, poor drainage or uneven ground forever. Taking the time to prepare the area properly helps your finished lawn stay smooth, secure and comfortable for years to come.
If you are replacing natural grass, preparation usually involves clearing the area, excavating the soil and creating a firm, free-draining base. Concrete, paving and decking require a different approach, so it is important to identify your existing surface before starting.
This guide explains how to prepare for artificial grass in seven straightforward steps. We will take you up to the point where the area is ready for the grass roll to be installed. For cutting, joining and securing the turf, follow our How To Lay Artificial Grass guide.
Why Proper Artificial Grass Preparation Matters
Artificial turf does not need soil, sunlight or watering, but it does need a stable foundation.
Without the correct preparation, your lawn may develop:
- Visible dips and bumps
- Loose or lifting edges
- Areas that move underfoot
- Standing water after rainfall
- Weeds growing around joins and borders
- Incorrect levels beside paths and patios
The preparation stage also gives you the chance to check drainage, plan the finished height and spot any potential problems before they cause issues.
It may be the least visible part of the project, but it is one of the most important steps in creating a smooth, long-lasting finish.
Check Your Existing Surface
Before ordering materials or starting to dig, work out what surface the artificial grass will be laid on.
Natural Grass Or Soil
Existing grass and vegetation will need to be removed before a suitable base can be installed.
You should also check the soil conditions. Firm, free-draining soil is generally more straightforward to prepare than heavy clay or ground that becomes waterlogged.
Follow our Installation On Soil Guide for the complete surface-specific process.
Concrete Or Paving
Artificial grass can be fitted over concrete and some paved surfaces, provided they are stable, clean and able to drain.
Check for:
- Loose or moving slabs
- Large cracks
- Uneven sections
- Water pooling after rain
- Sharp edges that could damage the backing
Our Installation On Concrete Guide explains the full method.
Decking
Decking should be structurally sound before it is covered. Check for loose boards, movement, rot and large gaps.
Artificial grass can improve the appearance of tired decking, but it should not be used to hide structural damage. See our Installation On Decking Guide for more advice.
Measure And Mark Out The Area
Measure the garden before removing the existing lawn.
For a square or rectangular space, record the length and width in metres. If the lawn has an irregular shape, divide it into smaller sections and calculate each area separately.
Take several measurements rather than assuming the boundaries are perfectly straight. Many gardens narrow slightly towards one end or contain small sections that are easy to miss.
Use our Artificial Grass Calculator to estimate how much artificial turf you will need.
When planning the layout, consider:
Each section of grass should face in the same direction. Planning this before ordering can reduce waste and help the lawn look more consistent.
Mark out the proposed perimeter using string, spray marker or small stakes. This gives you a clear line to follow when clearing and excavating the area.
Remove Existing Grass And Vegetation
Artificial grass should not be laid directly over an existing natural lawn.
Real grass, roots and other organic material break down over time. If they are left underneath, the surface can sink and become uneven.
For smaller gardens, the turf can usually be removed with a spade. A turf cutter may make the job quicker and more consistent across a larger lawn.
- Existing grass
- Weeds
- Visible roots
- Loose soil
- Stones
- Garden debris
- Old edging or damaged paving
- A skip
- Waste collection bags
- A licensed collection service
- Space to store soil temporarily
- Wheelbarrow access through the property
It is also worth planning what will happen to the removed turf and soil. Even a relatively small lawn can create a surprising amount of waste.
Be careful around trees, cables, pipework and drainage points. Large roots or unknown underground services may require professional advice.
Excavate To The Required Depth
Once the area is clear, excavate enough soil to make room for the base layers, weed membrane and artificial grass.
Many soil installations require around 70mm to 100mm of excavation, but the correct depth depends on:
- The ground conditions
- The sub-base specification
- The chosen pile height
- Drainage requirements
- The level of nearby paths and patios
Do not select a depth without considering the finished height.
The top of the artificial lawn should meet surrounding surfaces neatly. If the groundwork is too shallow, the grass may sit higher than a patio or path. If it is too deep, it can leave an awkward step around the perimeter.
Use a tape measure to check the depth in several places as you work.
The base may need to be deeper in areas with soft ground, poor drainage or heavy use. If the garden regularly holds water, address the cause before continuing.
Install Edging And A Suitable Sub-Base
The perimeter edging helps define the lawn and provides a secure point for the artificial grass to be fixed during installation.
Depending on the garden, suitable edging may include:
- Treated timber
- Recycled plastic rails
- Concrete edging
- Paving
- Sleepers
- Existing walls
The right option will depend on the shape of the lawn, the surrounding materials and the style you want to create. Our guide to artificial grass edging ideas explores different finishes for modern, traditional and family gardens.
Whichever material you choose, make sure the edging is secure, level and positioned at the correct height before moving on to the base
Many artificial grass installations on soil use a compactable aggregate such as MOT Type 1 or crushed stone. Spread the material evenly across the area, working it into the corners and edges with a rake. Avoid leaving deep piles in one place, as these can be more difficult to compact consistently.
The sub-base should provide:
A finer layer of granite dust or sharp sand may be added above the main base to create a smoother finish. The most appropriate build-up will depend on the soil and installation method.
Compact And Level The Base
A loose base may look level when it is first spread, but it can move and settle after the lawn is used.
Compact the aggregate using a plate compactor. For deeper bases, add and compact the material in stages rather than trying to compress one thick layer at the end.
Work across the full area, including the edges and corners.
After compacting, check the surface using a long straight edge and spirit level. Look for:
- Low spots
- Raised sections
- Loose aggregate
- Soft areas
- Sudden changes in level
Add more material to any dips, rake it smooth and compact the area again.
The base should feel firm underfoot without leaving deep footprints. It does not need to be completely flat if the garden relies on a slight fall for drainage, but it should be smooth and consistent.
Water should move towards an appropriate drainage point rather than towards the house, doors or garden buildings.
Add Weed Membrane And Complete Your Final Checks
Once the base is firm and level, install a permeable weed membrane.
Roll the membrane across the prepared area, keeping it smooth and flat. Where more than one piece is required, overlap the sections so there are no exposed gaps.
Secure the membrane using appropriate pins or fixing nails, then trim it neatly around borders, drains and obstacles using a sharp utility knife.
Avoid using solid plastic sheeting. The membrane should allow water to pass through rather than trapping moisture underneath the lawn.
Before opening the artificial grass roll, complete one last check.
Make sure:
- The perimeter edging is secure
- The base feels firm underfoot
- There are no obvious dips or ridges
- Drainage points remain accessible
- Water can move away from the lawn
- The membrane is flat and correctly overlapped
- The finished level allows for the grass pile
- All stones and sharp objects have been removed
Once these checks are complete, the area is ready for the artificial grass installation to begin.
You can find joining tape, adhesive, fixings and other essentials in our Artificial Grass Installation Accessories range.
Common Artificial Grass Preparation Mistakes
Most ground preparation problems are caused by rushing or missing one of the early checks.
Common mistakes include:
One small dip may not look serious while the base is exposed, but it can become much more noticeable once the artificial grass has been laid.
Correct any uneven or unstable areas before moving on.
When Is The Ground Ready For Artificial Grass?
The ground is ready when it is firm, smooth and able to drain.
You should be able to walk across the area without leaving deep marks. There should be no loose material, obvious hollows or sharp stones.
The edging should be secure, the weed membrane should sit flat and the finished level should allow the artificial lawn to meet nearby surfaces neatly.
At this point, you are ready to position the grass, allow it to settle and begin the fitting process.
Follow our How To Lay Artificial Grass guide for the next stage.
Artificial Grass Preparation FAQs
How Deep Should You Dig For Artificial Grass?
Many soil installations require approximately 70mm to 100mm of excavation. The exact depth depends on the soil, drainage, sub-base materials, pile height and required finished level.
Do You Need A Sub-Base Under Artificial Grass?
A suitable sub-base is normally required when laying artificial grass over soil. It provides structural support, improves drainage and reduces the risk of the lawn sinking or moving.
Can You Lay Artificial Grass On Soil?
Artificial grass can be installed in an area that currently contains soil, but it should not be laid directly onto loose ground. The area must first be cleared, excavated and given a suitable compacted base.
Do You Need Weed Membrane Under Artificial Grass?
A permeable weed membrane is recommended for most soil installations. It helps reduce weed growth from below while allowing rainwater to pass through.
What Is The Best Base For Artificial Grass?
A compacted aggregate such as MOT Type 1 or suitable crushed stone is commonly used as the main base for artificial grass. A finer levelling layer may then be added above it. The best specification depends on the ground conditions and intended use.
How Long Does Ground Preparation Take?
A small, straightforward garden may be prepared within a day, while larger areas or gardens with poor access and drainage can take considerably longer. It is better to allow enough time than rush the excavation, levelling or compaction stages.
What Happens If You Do Not Prepare The Ground Properly?
Poor preparation can lead to bumps, dips, movement and standing water. These issues may not appear immediately, but they can become more noticeable after regular foot traffic or wet weather.
Can You Lay Artificial Grass Directly Onto Grass?
No. Existing natural grass and vegetation should be removed before the new base is installed. Laying artificial turf directly over grass creates an unstable surface as the organic material underneath begins to break down.
Give Your New Lawn The Right Foundation
Preparing the ground may take longer than rolling out the artificial grass, but it is an essential step in creating a smooth, long-lasting lawn that looks great and can be enjoyed in your garden for years to come.
Clear the area thoroughly, create a firm base and take time to check the levels and drainage. Once the seven preparation steps are complete, you will have a much stronger foundation for a smooth, long-lasting artificial lawn.
Explore our Artificial Grass Installation Accessories or speak to our team if you need help choosing the right products for your project.
View Installation Accessories Use Our Grass CalculatorCall us on 01772 629654, email sales@artificialgrassdirect.co.uk or complete our online contact form and a member of the team will be happy to help.


