The cold winter weather can be tough on your lawn.
Winter desiccation (or winter kill) is the term used for turf dying in extremely cold temperatures. This happens when grass experiences severe moisture loss, causing the leaves to turn yellow. This can sometimes lead to the roots and crown of the plant dying. No turf is immune to winter desiccation.
Here are a few common causes of winter desiccation and what they mean for your lawn:
Frost damage is a common problem in Australian turf during the colder months. Frost occurs when the grass becomes colder than the air that surrounds it, usually on cold, clear nights. Frost damage causes the leaf blade to lose its colour but will rarely kill the turf. It will usually recover once spring arrives and the weather starts to warm up.
One of the main reasons why turf suffers from winter desiccation (but not so common in most of Australia) is crown hydration. Crown hydration normally occurs in late winter/early spring when the temperature warms up during the day. The turf starts absorbing moisture again in daytime but will be hit with freezing temperatures during the night causing any remaining moisture to freeze. Ice forms on the crown (the base of the grass) causing the cells to rupture, which kills the plant.
Snow mould (again, not so common in Australia) is a disease caused when snow sits on turf for a long time. Snow mould causes circle patches in lawns which can be as small as a couple of centimetres or as large as 30cm in diameter.
There are two types of snow mould. Grey snow mould is less damaging and will only burn the leaf of the grass. Pink snow mould is more serious as it will kill the crown and roots of the turf as well. Both grey and pink snow mould are unique diseases as they can survive the summer months under the ground or in plant debris.
Repairing Winter-Damaged Turf
Returfing is the most common method of repairing severely winter damaged turf. Returfing is best done in spring once the weather warms up. This involves removing any dead grass matter, reconditioning and levelling the soil, before laying new turf over the top. Or you may choose to reseed which can be done during the cooler months and involves the same process as returfing but by spreading new grass seed instead of laying cut turf.
When coming out of winter it’s important to fertilise your lawn. As the weather warms up, fertilising will provide vital micro and macro nutrients to your lawn that may have been lost over the harsh winter months. It’s a good idea to choose a nitrogen-rich fertiliser as this will help your lawn to repair any damage cause by cold temperatures.