What to put under artificial grass for drainage?

If you are thinking about installing artificial grass, you might be wondering what to put under artificial grass for drainage. Good drainage is one of the most important parts of a strong, long-lasting artificial lawn. When water drains well, it keeps your yard clean, dry, and safe. When it does not, puddles, bad smells, and even mold can form under your turf.

In this guide, you will learn what materials to use under artificial turf, how to build the right base layer, and how to make sure water drains easily through your new lawn.

Why Drainage Matters for Artificial Grass

Artificial grass or synthetic turf is made with small drainage holes in the backing. These holes let rainwater and washing water move through the turf and into the base layers below. If you use the wrong materials under your turf, the water cannot escape and will collect on the surface.

Poor drainage can lead to:

• Puddles and standing water
• Mud and slippery areas
• Mold and mildew growth
• Bad smells, especially in pet areas
• Damage to the grass backing

That is why having the right drainage system under your artificial lawn is so important. A good base helps water flow away just like it does with natural grass.

How the Drainage System Works

The drainage system under synthetic grass is made of layers that allow water to pass through each one until it reaches the soil or a drain below. These layers usually include:

1. A weed membrane or geotextile fabric
2. A sub-base layer made of crushed stone or decomposed granite
3. A thin leveling sand or grano dust layer
4. The artificial turf with small drainage holes

Together, these layers form a strong base that supports the turf and keeps your yard dry after rain.

In very wet yards, you can add French drains, perforated pipes, or drainage mats to help move more water away. These are small trenches filled with stones or pipes that carry water to a safe place like a storm drain or catch basin.

Step 1: Preparing the Ground

Before installing your artificial lawn, you need to prepare the area. This part of the installation process is called ground preparation, and it makes a big difference in how your lawn drains.

Clear and Level the Area

• Remove the natural grass, roots, and about 2–4 inches of topsoil.
• Make sure the area slopes slightly away from your house or patio so rainwater can run off. A slope of 1–2% works best.

Check Irrigation Lines

If you have sprinklers, remove or cap them. Many people use sprinkler caps or irrigation lines to prevent leaks before installing turf.

Apply Weed Killer

To stop weeds from coming back, use a weed killer or place a weed barrier cloth over the soil before adding the base materials.

Step 2: Building the Sub-Base Layer

The sub-base layer is the most important part of your drainage system. This layer gives your lawn strength and lets water pass through quickly.

Most professionals use crushed stone, crushed granite, or decomposed granite for this step. These materials have small gaps that let water flow easily between them.

Choosing the Right Base Materials

Here are some good options:

• Crushed stone (¾-inch or smaller pieces)
• Class II road base (a strong mix of crushed rock and sand)
• Crushed granite or decomposed granite for smooth, natural drainage
• Type 1 MOT or crushed limestone if you want a firm base

Spread the material evenly and compact it with a plate compactor or stamp compactor. Compacting helps the rocks lock together, making the ground stable and solid.

For regular backyards, make the sub-base about 2 to 4 inches thick. For play areas or driveways, use up to 6 inches. This helps handle more weight and rainwater.

Step 3: Add a Weed Membrane or Geotextile Fabric

After the crushed stone layer is compacted, place a weed membrane or geotextile fabric over it. This thin sheet lets water flow through but keeps soil and weeds from mixing into your base.

Some people also call it landscape fabric or weed barrier cloth. It is one of the easiest ways to stop weeds and keep your lawn looking neat. The fabric also prevents small soil particles from clogging the spaces between the stones, which keeps the drainage layers working well for years.

Step 4: Add a Thin Leveling Layer

Next, spread a thin layer (about half an inch) of fine material to make the surface smooth. You can use sharp sand, stone dust, rock fines, or grano dust for this layer. This is called the leveling sand or base layer.

This layer is not meant for drainage. It just makes the surface even so the turf sits flat. Once you spread it, use the plate compactor again to pack it down.

Step 5: Installing the Artificial Grass

Now it is time to install your artificial turf or synthetic lawn. Roll out the turf carefully over the leveled base. Make sure the grass backing lines up correctly and that the drainage holes face down.

Securing the Turf

• Trim the edges with a utility knife.
• Join the pieces with turf seam tape and glue.
• Fix the edges using landscaping nails, landscape staples, or a bender board.
• Around flower beds, use rubber edging strips or paver base to keep everything tidy.

During the installation process, make sure you do not block the small holes in the turf backing. These holes are key to your drainage system.

Step 6: Adding the Infill Layer

Once the turf is in place, you need to add an infill layer. This material helps the blades stand upright, adds weight to keep the turf in place, and improves water flow.

Good infill materials include:

• Silica sand – helps water flow and gives stability
• Zeolite infill or Zeofill minerals – helps with odor control and keeps the surface cool
• Recycled rubber mulch – soft for playgrounds or pets
• Pet-safe turf deodorizer – optional for pet areas

Brush the infill into the grass using a stiff broom or power brush. Spread it evenly until you see the blades stand tall again.

Step 7: Extra Drainage for Wet or Clay Soils

If your yard has clay-based soil or often floods, you may need more than just the normal base layers.

Here are some options:

French drain: a gravel trench with a perforated pipe that carries water away.

• Perforated pipe systems under the turf to channel water into a drain or garden bed.
• Drainage mats or plastic paver tiles that lift the turf and help water move underneath.

These upgrades cost more but are worth it if your yard gets heavy rain or has poor water drainage.

Common Mistakes to Avoid

When learning what to put under artificial grass for drainage, it helps to know what not to do. These are the most common mistakes people make:

     1. Using the wrong base material

Never use only sand or soil as the base. They hold water and become muddy.

     2. Skipping compaction

If you do not compact the sub-base layer, your turf will sink or ripple over time.

     3. Blocking the drainage holes

Do not cover the bottom of your turf with plastic or thick liners. It will trap water underneath.

     4. Ignoring the slope

Even with good materials, your turf needs a small slope so water can move off the surface.

     5. Not using a weed membrane

Without a weed barrier, weeds will grow through the turf and block the drainage holes.

Tips to Keep Good Drainage After Installation

Even after a perfect artificial turf installation, you should do a little care to keep the drainage system working well.

• Rinse the turf once a month to wash away dust and leaves.
• Brush the infill layer occasionally so it does not compact too tightly.
• Check the slope after heavy rain. If water pools, lift a small area to see if the base layer has shifted.
• Look for signs of mold and mildew growth and clean them right away.
• If pets use the area, rinse more often and refresh the infill material when needed.

Cost and Value of a Good Drainage Base

Many people worry about the cost of artificial grass, but the base work is where most of the value lies. A well-built base with quality base materials such as crushed stone, decomposed granite, and geotextile fabric can last 10 to 15 years without replacement.

Spending a little more on the right sub-base layer and installation techniques saves you from fixing puddles, bad smells, or sagging turf later. Companies like Petgrow often say that drainage problems are the top reason for early turf replacement.

So, if you plan to invest in synthetic turf, make sure your drainage layers are installed correctly from the start.

Conclusion

Knowing what to put under artificial grass for drainage helps you build a lawn that stays beautiful and functional all year long.

When done right, your artificial turf will drain quickly after rain, feel firm underfoot, and stay free of puddles and mold. You will enjoy a clean, green space without the work of maintaining natural grass.

If you are unsure about your soil or local rain levels, follow the manufacturer’s guidelines or hire a professional who understands turf drainage. A proper base today means a dry, healthy lawn for years to come.

Contact us today for more Information.