Renovation may be defined as a process of restoring a poor quality turf to good condition without completely tilling or removing the lawn. It is necessary to reconstruct heavily weed infested lawns or lawns with structural faults such as poor drainage or uneven levels. It is important before renovating to determine the cause or causes of deterioration of the lawn, then carry out a corrective program, otherwise you may have to repeat the process again in another year or two. Faults which can usually be corrected by renovating an existing lawn include low soil fertility, soil compaction, too much shade, undesirable grasses and general neglect.
If you are renovating your lawn, make sure you follow these three key areas.
Heavy traffic areas frequently become compacted. Nutrient intake is impaired, grasses die off from water-logging in winter, and scalding in hot weather, and thatch often develops. The lack of deep irrigation reduces root depth and the lawn becomes less tolerant to drought or infrequent irrigations. Weakened turf grass is also more susceptible to a number of diseases.
Generally speaking, both thatch and compacted soils cause the same problem in that they prevent intake of nutrients.
For heavily compacted soils, coring needs to be undertaken. This can be done by a coring machine, leaving a hole or cavity in the turf to a depth of about 7.5 – 10 cms. These holes then allow water to penetrate down into the root zone, while at the same time providing adequate drainage. After coring spread Gypsum and coarse sand over the area.
Scarifying (Verti – mowing)
All lawns build up thatch from time to time and a small amount can be beneficial to the lawn as it helps prevent evaporation, aids water retention and gives increased tolerance to wear and tear. However, when the accumulation of thatch reaches a point where it impedes water, air and fertiliser penetration, then scarifying needs to be carried out.
Scarifying can be achieved by slicing vigorously through the turf with a scarifying rake or a scarifying machine and removing the debris. The best time to carry out this procedure is from October to December on Warm season grasses (running type) and September/October on cool season grasses (upright growth).
Top dressing is utilized for smoothing or levelling turf. Surface top dressing is one of the most effective controls of limited thatch and should be carried out when the lawn is at optimum growth stage.
Before top dressing cut the lawn down close, if you haven't fertilised the lawn recently, give it a feed and water in well, then lightly top dress no more than 2cm. Top dressing soil should be clean, free of pests and weeds, and be of a good sandy loam consistency. Spread the soil as evenly as possible over the area.