Lawn Repair after Autumn Flooding

Lawns such as Sir Walter handle flooding rains quite well but what happens after the flood waters have receded – what is the best way to repair your lawn from the damage it has suffered?

 

There isn’t a lot you can do while the rain still falls and until the water has drained away. In fact, it’s best you don’t do anything to your lawn until then.

 

Damage to your lawn will depend greatly on the length of submergence, the water depth and temperature, the variety of grass, the light intensity and the condition of the lawn prior to the flooding.

 

Turf in flooded conditions will decline from a combined lack of oxygen and light but most damage won’t occur unless the lawn has been submerged for over 4 days.

 

The damage can be caused by:

  • Suffocation from long term submersion or remaining debris
  • Silt and sand coverage
  • Water contaminated with petroleum products and pesticides
  • High water temperature scalding the lawn plants
  • Algae scum

 

Once the waters have receded you should remove any debris that may cause a safety hazard to people walking on the lawn or using equipment such as mowers.

 

After that, the repair tasks are determined by the amount of silt or sand deposits left on your lawn.

 

Lawns with silt/sand deposits up to 2.5cms deep (usually minimal – to moderate damage):

 

If you have no water restrictions in your area or have your own water supply, use a garden hose to was away as much silt as possible from the lawn;

 

Break up the remaining silt crust throughout the growing season or until the lawn is re-established to encourage root development. You can use a steel toothed rake to do this but be careful to not push too deeply or you will pull the turf out;

 

Apply a quick release nitrogen fertiliser at the rate of 250gs per 90 square metres of lawn area;

 

Have the soil tested to determine the rates of lime, phosphorous and potassium and the requirements of your lawn post-flooding.

 

Lawns with silt/sand deposits more than 2.5cms deep (may be heavily damaged):

 

Remove as much of the silt as possible, as soon as possible after the water recedes;

 

If the silt is less than 7.5cms or has been removed to this depth, till the area, making sure that the silt is mixed thoroughly and uniformly into the top 10 to 15 cms of the original soil;

 

Re-plant the areas as you would to establish a new lawn. Do not sod over existing dead or buried vegetation. The old dead layer of grass must be thoroughly tilled into the soil before laying new sod.

 

Flooded but no silt/sand deposits left:

 

Apply a top dressing if a significant amount of soil has been washed away or there are now bare patches in your lawn;

 

Apply a quick release nitrogen fertiliser at the rate of 250gs per 90 square metres of lawn area;

 

Have the soil tested to determine the rates of lime, phosphorous and potassium and the requirements of your lawn post-flooding.

 

You should also keep any eye on any recently flooded lawn regardless of obvious damage – flooding can make your lawn susceptible to pest and weed invasions as the lawn struggles to regain its condition and repair. If you have suffered significant flooding damage and need to relay part or all of your lawn, contact the team at Daleys Turf for advice on the best variety of turf for your yard.

 

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