Choosing the right artificial grass is important, but choosing the right sub-base matters just as much. A good lawn does not only depend on the grass you see on top. It also depends on what is underneath it.
If the sub-base is wrong, even high-quality artificial grass can end up looking uneven, draining badly, or sinking over time. If the sub-base is chosen and installed properly, the lawn has a much better chance of staying level, draining well, and lasting for years.
If you are planning a new artificial lawn, this guide explains how to choose the correct artificial grass sub-base, what options are commonly used, and how to decide what works best for your garden.
What Is an Artificial Grass Sub-Base?
An artificial grass sub-base is the layer of material laid underneath the grass to create a firm, stable, and free-draining foundation. It sits between the ground below and the artificial grass above.
This layer does a lot of important work. It helps support the lawn, improves drainage, reduces movement, and gives the final surface a more even finish. Without a proper sub-base, the grass may shift, wrinkle, develop dips, or collect water in low spots.
In simple terms, the sub-base is what helps the lawn perform like a lawn rather than just a roll of grass laid over the ground.
Why the Sub-Base Matters So Much
It can be tempting to focus only on the look or feel of the artificial grass itself, but the base underneath is what supports everything.
A well-prepared sub-base helps with:
Stability
It creates a firm surface that can cope with foot traffic, garden furniture, and daily use without sinking or moving too easily.
Drainage
It helps water pass through and away from the lawn, which reduces the chance of pooling after rain.
Longevity
A stable foundation can help artificial grass stay in better condition for longer and reduce future issues.
Overall finish
Even the best artificial grass will not look quite right if it is laid over an uneven or unstable base.
This is why the sub-base is one of the most important parts of the installation process. It is also one of the reasons homeowners comparing artificial grass in Warwick or other local options often find that the finish of the lawn depends as much on preparation as it does on the grass itself.
Can You Lay Artificial Grass Straight Onto Soil?
In most cases, this is not the best idea.
Laying artificial grass directly onto soil can lead to several problems over time. Soil moves naturally depending on moisture, temperature, and use. It can become soft when wet, compact unevenly, or shift under pressure. That movement can cause the grass above to dip, crease, or wear unevenly.
Soil on its own also tends to be less reliable for drainage. In wetter conditions, this can lead to puddling or soggy patches underneath the grass.
That is why a proper sub-base is usually recommended if you want the lawn to stay stable and look good over the long term.
Common Types of Artificial Grass Sub-Base
There is no single sub-base that suits every project. The right one depends on the surface, the amount of levelling needed, the expected traffic, and how the garden will be used.
Here are the most common options.
Crushed Granite
Crushed granite is one of the most popular choices for artificial grass sub-base. It compacts well, creates a firm finish, and offers good drainage.
This makes it a strong option for many standard garden installations, especially where the area does not need major raising or heavy structural support. It is often used where natural grass, shingle, or paving has been removed and the ground only needs moderate preparation.
Crushed granite can be a very good choice when you want a balance of drainage, stability, and a neat finished surface.
MOT Type 1
MOT Type 1 is often used where more strength and build-up are needed. It is made from larger aggregate and fines, which allow it to compact into a harder and stronger base.
This can be especially useful when:
- the area needs raising by more than a shallow depth
- the garden ground is soft or unsettled
- a flowerbed, pond, or previously disturbed area is being covered
- there is a greater risk of sinkage over time
In some installations, MOT Type 1 is used as the lower structural layer, with a finer material such as crushed granite placed above it to improve levelling and drainage.
Aggregate Without Fines
For some pet-friendly areas, an aggregate without fines may be preferred because it encourages cleaner drainage. This can help reduce the chance of odour building up in lawns used regularly by dogs.
If the lawn is mainly being designed for pets, drainage becomes even more important, so the base choice should reflect that. In those cases, it also helps to think about whether the finished lawn needs to be more suitable for artificial grass for dogs and day-to-day pet use.
Sand and Other Surface Layers
Some installations may also include a finer levelling layer depending on the project and the condition of the ground. The exact build-up can vary, but the main aim is always the same: a compacted, stable, level, and draining base that suits the area.
How To Choose the Right Sub-Base for Your Garden
The best way to choose the correct artificial grass sub-base is to look at the site conditions first rather than picking one material for every job.
1. Consider the Existing Surface
Start by looking at what is already there.
If you are replacing natural grass in a fairly level garden, a compacted granular base may be enough. If you are covering an area that was previously paved, a flower bed, loose soil, or something that has been recently disturbed, you may need a stronger or deeper build-up.
The starting surface tells you a lot about how much support the new lawn will need.
2. Think About Drainage
Drainage should always be part of the decision.
Gardens that already hold water, clay-heavy ground, or areas with poor runoff need extra care. A well-draining sub-base helps water move through the system rather than sit under the grass.
If drainage is poor from the start, the lawn may not perform well even if the grass itself is high quality.
3. Check How Much Levelling Is Needed
Some gardens only need a shallow layer of base material. Others need more work to correct dips, uneven sections, or changes in level.
If the area needs to be built up significantly, a stronger structural base may be the better option. In many cases, deeper areas are best built up in layers and compacted as the work progresses.
4. Think About How the Lawn Will Be Used
A small decorative area may not need the same base as a busy family garden.
If the lawn will be used by children, pets, or for regular entertaining, the base needs to cope with more traffic and wear. If furniture will sit on the surface regularly, a firm and stable sub-base becomes even more important.
5. Do Not Ignore Long-Term Performance
It is easy to focus on what looks quickest or cheapest in the short term, but the sub-base affects how the lawn performs over the years.
Choosing the correct base from the beginning can help reduce the risk of movement, poor drainage, and avoidable repair work later on.
Basic Steps in Preparing a Sub-Base
While every project is slightly different, the process usually includes the same core stages.
First, the area is cleared of existing grass, weeds, debris, or old surface material. Then the ground is excavated to create space for the new build-up. After that, the chosen sub-base material is added and compacted thoroughly to create a firm foundation.
A weed membrane is often included to help reduce weed growth from underneath. Once the base is level and draining properly, the artificial grass can be installed on top.
The key point is that the base should not just be tipped in and left. It needs proper preparation and compaction if you want the lawn to perform well.
Common Mistakes To Avoid
A lot of artificial grass issues start below the surface. These are some of the most common mistakes:
Laying directly on soil
This often leads to movement, unevenness, and drainage problems.
Choosing the wrong base material
Not every surface needs the same solution, so the base should match the site conditions.
Skipping compaction
Even the right material can fail if it is not compacted properly.
Ignoring drainage
A lawn that cannot drain well is likely to develop problems later.
Using too little depth
A shallow or weak base may not provide enough support for long-term performance.
Why Choose Artificial Super Grass
At Artificial Super Grass, a good-looking lawn starts with more than the grass itself. The final result depends on preparation, proper support underneath, and choosing the right approach for the space.
The right sub-base helps artificial grass stay level, drain better, and cope with everyday garden use more effectively. Whether the area is a family lawn, a pet space, or part of a full garden refresh, getting the foundation right is one of the best ways to achieve a cleaner and longer-lasting finish.
Final Thoughts
If you want your artificial lawn to look good and last well, choosing the correct artificial grass sub-base is one of the most important decisions in the whole project.
A good sub-base supports the lawn, improves drainage, reduces movement, and gives the final installation a much better finish. The right choice depends on the existing ground, how much levelling is needed, how the space will be used, and how important long-term performance is to the project.
When the foundation is done properly, everything above it has a better chance of staying neat, stable, and easy to enjoy for years to come. And if you want to compare options before you commit, ordering an artificial grass sample pack is a simple way to make a more confident decision.