Why does artificial grass get so hot, and can I cool it?

This surprises people who expected a low-maintenance lawn and got a surface their dog will not walk on. It is not a fault in the product or the installation; it is what a dark, dense plastic surface over a compacted base does in sunshine. Worth understanding before installation, and worth managing afterwards.

Safety

Step by step

1. Understand why real grass stays cool.A living lawn draws water from the soil and evaporates it from the leaf surfaces, and that evaporation removes a large amount of heat — the same mechanism that cools you when you sweat. Grass also grows in soil that holds moisture and buffers temperature. Artificial grass has neither: no water, no transpiration, and usually a compacted aggregate base beneath it.
2. Know how hot it can get.Surface temperatures on artificial turf in strong sun run far above the air temperature, easily hot enough to be uncomfortable underfoot and to injure a dog's paws. Check with the back of your hand for several seconds before letting anyone onto it — a much better test than the air temperature.
3. Shade it, because that is what works.Shade is the only measure with a large and lasting effect. A shade sail, an awning, a parasol positioned over the area, a pergola or a tree to the south-west all bring the surface temperature down substantially and keep it down. Everything else is a temporary measure.
4. Accept that watering is a short-term fix.Wetting the surface does cool it, by evaporation, and the effect is real but brief — typically around twenty minutes in strong sun before it is hot again. It is a useful thing to do just before children or a dog go out, and it is not a solution.
5. Think about colour and infill if you are still choosing.Lighter-coloured products run cooler than very dark ones, and the infill material matters — some infills store and radiate more heat than others. If artificial grass is going into a south-facing garden that gets full sun all afternoon, these choices are worth making deliberately.
6. Keep dogs off it in strong sun.Paw pads burn on hot surfaces and dogs will often keep walking on it rather than showing distress immediately. Provide a shaded area, a cool mat or a paddling pool, and use the hand test before letting them out. This is the most common real-world harm from hot artificial grass.
7. Expect it to radiate heat into the garden.A large area of hot plastic warms the air above it and radiates heat towards adjacent walls, seating and rooms. A conservatory or patio door facing a big expanse of artificial grass receives noticeably more heat than one facing a lawn.
8. Keep it clean, since that helps slightly.Debris and organic matter on the surface reduce drainage and can make it hotter and less pleasant. Brushing it regularly keeps the fibres upright, which slightly reduces the density of the surface presented to the sun and helps it perform as intended.

Tips

• The back-of-the-hand test for several seconds is the practical rule, and it is the same test used for pavements before walking a dog.
• Hot artificial grass near a house heats the rooms behind the glass it faces. If a conservatory or patio doors already overheat, a large expanse of it directly outside makes that worse.
• A cheap paddling pool or a damp towel in shade gives a dog somewhere to cool down that is far more effective than watering the whole lawn.
• Artificial grass over a solid base also sheds water rather than absorbing it, which matters for drainage as well as for heat.
• If you are considering installing it partly for a dog, the summer surface temperature is worth weighing against the convenience.

Common mistakes

• Assuming it behaves like a lawn in the sun — A living lawn cools itself by evaporating water. Artificial turf cannot, so it behaves like any dark plastic surface and runs far hotter than the air.
• Letting a dog onto it without checking the surface — Paw pads burn on hot surfaces, and dogs frequently do not react until damage is done. The hand test takes five seconds.
• Relying on watering it to keep it cool — The cooling lasts around twenty minutes in strong sun. It is a pre-use measure, not a solution.

Alternatives

• Shade sail or awning over the area: The one measure that substantially and durably reduces surface temperature. Needs secure fixing and to cope with wind.
• A tree or tall planting to the south-west: Shades exactly when the sun is strongest, cools the whole garden, and improves it in every other way. Slow but permanent.
• Wetting before use: Cools for roughly twenty minutes. Genuinely useful immediately before children or a dog go out, and not a fix.
• Lighter-coloured turf and cooler infill: A decision available only before installation, but a meaningful one in a full-sun garden.
• Returning part of the area to planting: Beds, gravel with plants, or a real lawn in the sunniest section reduces both the heat and the radiated load on the house.

Questions people ask