What do frost and snow do to lawns?

UK lawns are well used to frosty mornings and the occasional dump of snow. We all know that it’s damaging for a lawn to walk on it when it’s frosty but we may not know exactly why that is. In this blog, we look at why that is and how best avoid damage and keep the lawn looking perfect all winter long.

British lawns can actually tolerate our winters rather well. Most of the grass species in the UK can survive temperatures down to -20 degrees Celcius. The frost alone will not kill grass, if the lawn is left untouched it will probably manage very well! In freezing temperatures nutrients can’t move around the plant as quickly so the lawn goes into dormancy, it’s life processes just ticking along until the weather improves.

Water is the main constituent of plant cells when it freezes it creates ice crystals. Traffic on the lawn in frosty conditions causes the sharp-edged ice crystals to rupture the cell walls and cause lasting damage to the leaves. Because the plant is in a dormant state, this damage will not heal very quickly but the plant is unlikely to die, it will bounce back eventually. If the frost is very severe and the ground is also frozen then walking on the lawn will cause damage to the roots which is more likely to kill the plants.

Plants have the ability to protect themselves from frost. As winter approaches they build up carbohydrate reserves in their cells which lowers the temperature at which they freeze (a natural anti-freeze, if you like). This happens at the end of autumn when the temperature starts to drop. Plants also use these carbohydrates to grow, so if too much nitrogen is applied at this time of year the plant will not be able to build up reserves and the damage levels will be higher when the frost does arrive. Low nitrogen feeds such as First & Last and AutumnGreen are best suited for autumn applications.

Snow is quite different to frost, it tends to insulate the ground so the lawn is not subject to such cold temperatures. Unfortunately an air gap forms between the snow and the ground which is quite warm and moist, perfect conditions for fungal disease. Diseases such as snow mould will take advantage of this and are far more likely to kill the grass than the snow or ice itself. Clearing snow will help avoid disease but you risk damaging the grass anyway so it’s best left alone, not possible though if there are children involved, snowmen will be making an appearance!


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