First frosts: How does frost affect your lawn?

One frosty morning in a week shouldn’t do too much damage to your lawn. When frost is a regular occurrence in your region, you may need to consider the lasting effect it may have on your grass. Remember that frosty grass is weakened when you (or your pets) walk on it - and this is one of the reasons patches of dead grass appear on your lawn.

How does frost form?

Frost is essentially water vapour that freezes when an outside surface cools past ‘the dew point’. The dew point is when the water vapour (gas) turns into a liquid because it is so cold, and therefore forms on the grass and freezes the blades. This happens overnight as air temperatures drop. You will then notice that most frost will disappear mid-morning as temperatures become milder and your grass begins to thaw.

What damage can frost do to my lawn?

Frost freezes your grass blades and makes them rigid and brittle. Much of grasses’ ability to ‘bounce back’ from wear and tear is its flexible blades. When cold winter frosts remove your lawn's ability to do this, it will be much more likely to show signs of ill-health as winter takes its toll.

How can I stop frost from damaging my lawn?

Pre-frost preventative measures:

Apply a lawn fertiliser

Just like us, your lawn has an immune system that needs to be built up over time. You can aid this by applying a granular autumn/winter fertiliser that is high in potassium to give your lawn up to 4-months of protection from the cold weather of winter.

Alternatively, you can use a quick-release autumn/winter liquid fertiliser that is fast-acting and gets to work instantly after applying, feeding your lawn an intensive feed of nutrients for 6-8 weeks. Both options will help strengthen your grass's resilience to disease and frost, ensuring it's healthier, greener and in better condition after winter ends.

It's best to apply our fertiliser anytime from August to October - this gives your lawn the ultimate protection from winter disease and frost during the cold winter months.

Your lawn will not have the nutrients it needs to fight winter-borne diseases and may succumb to them if you decide not to feed it with fertiliser before winter. If you have a relatively young lawn (sown in spring or summer this year), we recommend applying fertiliser in autumn to ensure your grass is ready for cold weather when it arrives.

Don’t mow your grass too short

When planning your last mow of the season, make sure to mow a little higher than your usual setting. You also need to make sure that your mower blades are sharp. Be aware that cutting on a low setting with a blunt blade can sever the cells within your grass, which stops them from being able to repair and grow again.

Post-frost actions:

Don’t walk on the lawn

The most obvious way to stop frost from damaging your lawn is not to add to the problem. This means staying off the lawn when there is frost – and this goes for your pets too! Grass blades that are walked on when frozen can split and break. And when your lawn wakes up again in spring, it can appear yellowed/brown or dead.

Repair in early spring

If your lawn does emerge damaged in spring, you can, of course, repair it – but to avoid this happening year after year, using the above advice will help cut out this extra work!

We also have some quick tips to help you make sure your garden is ready for winter, and we have some further reading to ensure your lawn stays in shape all year:

• Lawn Care Calendar
• Lawn Care Seasonal Checklist
• How to revive your lawn after winter