Once the flood waters have receded and the homes are recovered, it will be time to clean up the yard.
Common sense would tell you to pick up any debris, such as wood, glass, stones, nails and other metal objects, deposited on lawn areas. This debris is a safety hazard to operators and can damage mowers or other equipment used on the lawn. Remove leaves or any other material that smothers grass.
Turf in flooded conditions declines from lack of oxygen and light. Substantial turf loss can be expected after 4 days of continued submersion. Other factors associated with flooding also damage turf grass, i.e. silt/sand cover, water contaminated with petrol or pesticides, high water temperature and algae scum.
As flood waters recede, sun and high temperatures can literally cook the turf in its soggy surroundings.
Silted lawns — 1 inch or less
Lawns submerged less than 4 days and covered with an inch or less of silt have a good chance to recover.
To assist recovery:
If water use is unrestricted in your area, use a garden hose to wash as much silt as possible from the lawn.
To encourage root development, keep the remaining silt crust broken throughout the growing season or until grass is well established. Use a steel tooth garden rake.
Apply a nitrogen fertilizer to the lawn.
Have the soil tested as soon as possible to determine lime, phosphorous and potassium requirements. Follow the recommendations given with the soil test report.
Silted lawns — more than 1 inch
Lawns covered with more than 1 inch of silt may be heavily damaged, with only a slight chance of recovery. Degree of recovery will vary with grass species and depth of silt.
Re-establish the lawn as follows:
Remove as much silt as possible, especially if silt accumulation exceeds 3 inches, as soon as possible after water recedes.
If silt is less than 3 inches or has been removed to this depth, till the area, making sure silt is mixed thoroughly and uniformly in the top 4 to 6 inches of original soil.
Re-plant the areas as you would to establish a new lawn.
Do not turf over existing dead or buried vegetation. The old dead layer of grass must be thoroughly tilled into the soil before laying new turf.
Flooded lawns (not silted)
Degree of injury will depend on duration of submergence, water depth, temperature, grass species, light intensity and the condition of grass prior to flooding.
Most grasses will survive 4 to 6 days submergence at normal summer temperatures. Aerate and lightly fertilize flooded areas as soon as possible after water recedes. Areas submerged more than 4 to 6 days may not survive and will require complete re-establishment as previously noted.
Got questions? Wild Horse Turf are available to talk you through the recovery process – call Jess in the office 54969790.
This information has been adapted for Australian conditions from research by the University of Missouri. You can read the original here: https://extension.missouri.edu/publications/g6722