Most important is the satisfaction of having a nicely groomed, healthy lawn. Perhaps your lawn is not looking that bad. However, a little foresight and an understanding of what the lawn needs at di?erent times during the year can prevent unhealthy conditions from developing. What is done now will be beneficial all summer. The following remedial and preventative action will maintain your lawn in good health and have it looking good throughout the summer.
Mowing: Fine turf species, like browntop and fescue, like to be mowed short. For the home garden, a good height is around 20mm. Mowing weekly is a summer requirement and clippings should be removed. If the grass is consistently longer, then thatch build-up occurs: thatch is a tightly intermingled layer of living and dead stems, leaves and roots which accumulates between the layer of actively-growing grass and the soil underneath. Rye grasses can be mowed longer, comfortably 30mm. Sharp blades produce a better result on any type of mower.
Watering: The most misunderstood lawn activity is watering. The ultimate aim is to maintain a soil moisture content between soaked and dry (known as field capacity and permanent wilting point). This can generally be achieved by one good early-morning watering per week, with two during very hot periods.
Never water every day. It wastes water and it encourages disease, thatch and weak, shallow-rooting plants. There is no fixed rule to how long to water. It depends on your soil type and method of application. Generally, irrigation is not required between April and October. An excellent idea is to apply a wetting agent to the lawn areas three times over the summer, starting now. This assists with moisture retention in the soil, reducing the watering requirement during the summer. Wetting agents are a must on sloping lawns and old, mature or thatchy lawns.
Thatch control: Excessive thatch (over 1.5cm thick) creates a favourable environment for pests and disease so needs to be controlled. Spring and early autumn is the best time to scarify lawns to remove any surplus thatch. If the lawn is thin or the renovation was particularly aggressive, it is beneficial to follow this by topdressing and oversowing. If oversowing, identify the current grass types and match the seed to it. Specialist help may be required to identify the lawn type. The risk is having multiple grass types in your lawn giving variable texture, colour and growth rates.
Caterpillar and grub control: Many lawns can appear quite hungry and yellow at this time of year. They have often been chewed to bits by overwintering grass grub, porina caterpillars and other chewing insects. The grubs will now be preparing for adulthood and breeding, ready to lay millions of eggs into the lawn to start the entire process over again. Control is easily done with a soil insect killer applied at a rate of 100g to 20sq m. Leave the pellets on the surface for a couple of nights so that the caterpillars are treated. They surface feed during the night and live deep in a burrow during the day. Water the pellets down into the soil after two days. This is to treat any grass grubs that might be present.
Weed control: Spray unwanted weeds with a selective herbicide (one that kills or stunts weeds in lawn grasses with little or no harm to the grass). There are many products available, some general and others that are specialist products to target individual weeds. Read and understand the label before applying. Thoroughly clean spray equipment after each spray. Many disasters have occurred when nonselective herbicides, have been applied to lawns. Moss is most evident in late winter and can be controlled by using a commercial moss killer.
Fertilising: This is best carried out three times a year – September, January and April are the best months. Slow-release lawn-specific fertilisers are best as they slowly release nutrients over eight to 12 weeks. Slow-release fertilisers also reduce the mowing requirements, especially in the initial weeks after application.
Relevelling: To fill in holes or patches that have occurred in the lawn, topdress with soil or topdressing mix but never smother the grass entirely. The best way to fill low areas is to apply a little often and sweep it into the turf. If the turf is smothered, then it should be overseeded and treated like a new lawn area. Beware, however, of subsidence as the turf layer below decays. A simpler way is to scrape o? the sunken area with a spade, level with some new soil and lay Ready lawn. Job done!