Best Sub Base for Artificial Grass for a High Quality Install

Artificial Grass

Have you ever wanted a picture perfect lawn but don’t want to go through the time consuming chore of maintaining one? Well the answer is simple: get artificial grass. 

Artificial grass, also called artificial turf or synthetic grass, is a layer of fiber-like material that is an alternative to natural grass and is shaped and colored to resemble blades of grass. Artificial grass comes in different shapes to resemble a specific type of grass and can be cut into different sizes to better fit a lawn.

Synthetic grass was originally used for sporting venues like football or soccer fields but have grown in popularity with homeowners in recent years. If you can imagine being on vacation for a week or so and not having to worry about weeds or grass growing out of control, then it’s pretty clear why artificial grass is becoming so popular. 

But how can you install artificial grass and what needs to be done beforehand? Can you simply plop down a layer of artificial grass on some soil? The answer is NO. 

There are a number of things that you need to do first before installing artificial grass. The most important factor, and our topic for today, is finding a good sub base for your artificial grass. Using the right sub base for your artificial grass will help it last longer and be more viable for use for yard activities like barbeques. There are different types of sub base that each have their own pros and cons. In this article, we’ll be going over the most common and the best sub base for artificial grass.

Table of Contents

Best Artificial Grass Sub Base: A Comprehensive Guide

Types of Sub Base

There are different types of sub base materials that can be used as for artificial grass. Here are some of the most commonly used materials as a sub base for artificial grass.

Crushed Miscellaneous Base (CMB)

Crushed Miscellaneous Base (CMB)

Crushed miscellaneous base, also called CMB for short, is a combination of crushed up concrete, also known as recycled concrete, or asphalt mixed together with gravel, limestone and sand. This is one of the more common types of sub base for artificial grass because it is easy to find and source. The chunks in CMB are large enough to let some water through, allowing for better drainage, yet sturdy enough to not be easily deformed when you step on it. After all, crushed up cement is still cement and is dense enough to support a lot of weight especially when compacted.

CMB is cheaper than other options for sub bases and is considered by many to be the default choice by homeowners. It does have its disadvantages. During installation, CMB can be challenging to flatten properly without the proper tools and does not offer as much drainage as decomposed granite because of the smaller compact nature of CMB.

Type 1 MOT 

Type 1 MOT 

Type 1 MOT is a type of aggregate commonly used in construction as a sub base for roads and sporting venues like football pitches. This is an expensive alternative and is used more for commercial purposes rather than residential properties. Type 1 MOT can be made with different materials such as crushed limestone, granite and concrete. A sub base layer of Type 1 MOT can provide great support and stability for high traffic roads and is meant to be easy to flatten because of the different sized particles. When used for residential properties as a sub base for artificial grass, Type 1 MOT  provides the best support and prevents any deformation or sinking but does not provide good drainage.

Decomposed Granite (DG)

Decomposed Granite (DG)

Decomposed granite, also called DG for short, is made of chunks of granite that have weathered down to the point that it breaks down into smaller pieces. Decomposed granite is an excellent choice as a sub base for artificial grass because it easily allows water to pass through it while still providing ample support. DG is also commonly used for pathways and even growing bonsai trees because of its pleasant appearance and its good drainage. The downside of DG is that it is more expensive than CMB and you will need to buy more sacks of DG because of its smaller particles.

Sub Bases NOT to Use for Artificial Grass


Sand is a type of material that is made up of finely broken up pieces of rock. The particles of sand are usually tiny and are made of minerals like silicon or aragonite. Sand is a common ingredient to make cement but is a bad sub base for artificial grass. It doesn’t offer much support, deforms easily, holds water instead of letting it drain and can be hard or expensive to source.


Mulch is a type of material that is commonly used in gardens or for pathways. Mulch is made up of wood chips, grass clippings, leaves or bark chips and is great at promoting the health of the soil as it breaks down naturally. Mulch is a bad choice as a sub base for this reason and could potentially lead to the growth of weeds or other plants beneath your layer of artificial grass. Mulch also absorbs water pretty well and acts as an insulator which prevents the water from evaporating. This could lead to mold growth. Mulch is a much better choice for those looking to actually grow their garden or lawn instead of using artificial grass.

Important Factors to Consider

Type of Surface


It is important to take note of what type of soil makes up your lawn before removing the top layer and applying any sub base. The type of soil that your lawn has would help you make a better decision on what type of sub base to use. Soil that has bad drainage like clay will require you to use a sub base that has good drainage to compensate for this or even to create channels where water can pass through. On the other hand, loam-like soil would have no issue absorbing water and will let you use any type of sub base for your artificial grass. 


Cement acts as a great surface for artificial grass. Cement provides great support and a solid foundation that will let water freely flow on it. For cement surfaces, you won’t need a sub base and can apply a layer of artificial grass directly on its surface. This makes it viable to apply artificial grass on balconies or porches that you feel need a more natural look.


The weather in your area is another important factor to consider. If it rains a lot in your area, you might want to consider getting a sub base that has good drainage. Snow will eventually melt and so, it is also important to get a sub base that would handle the amount of water. Hot temperatures are usually not a problem for artificial grass or the sub base. In fact, one good reason to get artificial grass is if you live in an area that has high temperatures that would make maintaining or growing a lawn much more difficult.


Drainage is one of the most important factors to consider when looking for a good sub base for artificial grass. A sub base with good drainage would let the water seep through properly and let it be absorbed by the soil. You could also create small channels or canals around the sub base, giving the water a clearer path to where they could seep into the soil faster. Good drainage is not just important for rain water but also for pets who might urinate on the artificial grass or in case one of your guests spills their drink during an outdoor barbeque. 

Existing Plants

Taking into consideration the current plants in your lawn is important because installing a sub base for your artificial grass requires you to completely remove the top soil of your lawn. This will effectively kill any and all plants that are currently in your lawn. In case you want to keep any of the plants growing in your garden, we recommend you put the plants you like in pots and arrange them around your artificial grass instead of throwing them away.

Size of Lawn

Lastly, the size of your artificial lawn is an important factor to consider because it would help determine how much sub base you would need and how much you would be spending. Sub base is commonly sold in sacks or by truck load and can cost hundreds of dollars depending on the type and amount of sub base you need. Sub bases such as DG will require you to buy more simply because of how small the particles of DG are.


Q: Why can’t I put artificial grass on soil?

A: Putting artificial grass directly on soil is a bad idea for several reasons. For one, soil does not provide the best support for artificial grass and could potentially deform or sink. This is because the soil is usually helped by the roots of plants for support and would be less stable without them. Another reason is that most types of soil absorb water very easily. This makes the soil expand or contract and could lead to wrinkles or air pockets forming in your artificial grass.

Q: How do I flatten out the sub base?

A: If you’re planning to install a sub base manually, you would need some tools to flatten it out evenly. Some tools you could use include a rake, hoe or a shovel. If you need more power for your artificial grass installation, you could use a plate compactor power tool or even rent out a small road roller. 

Q: Can I use different types of sub base?

A: Yes! You absolutely can use different types of artificial grass sub base. If you don’t mind the extra effort and expense, using two or more layers of sub base would give your artificial grass even more support. For example, you could use a thinner layer of DG or granite dust over a thicker layer of CMB to recreate a multilayered sub base.  


Sub bases are a useful and necessary part of installing artificial grass. We hope that this article has taught you a thing or two about the different types of sub base, how they differ and that you leave here with a better understanding on which sub base is best for you and your artificial grass.

Check out our picks for the best artificial grass to use in your next project!

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