Lawns have a role to play in modern gardens because they reduce heat in summer and improve air quality
With soaring summer temperatures experienced across the country, plants are taking strain and your lawn is no exception. If you are contemplating removing lawn and replacing it with hard landscaping or artificial lawn, don’t be too hasty.
Despite a move towards low-maintenance and more water-wise gardens, lawns still have a role to play in the city.
“Natural turf grass controls soil erosion as the root system grows into the soil and can be used to hold soil on a gentle slope,” says Fanus Cloete, chief executive at Evergreen Turf. “Lawn also reduces heat when compared with hard rock surfaces, asphalt and concrete.”
Cloete says on hot days, the temperature on grass may be around 170C or 180C, compared to 550C on asphalt.
“Grass also plays a role in capturing dust, smoke particles and other pollutants so air quality is improved.”
Lawns provide a place for entertainment and for children and pets to play. Like all plants, it absorbs carbon dioxide and releases oxygen.
Buffalo grass (Stenotaphrum secundatum) and indigenous Cynodon species that are able to withstand drought are recommended for the winter rainfall Western Cape region. Gulf Green, a Cynodon variety, is bright green in colour and suitable for a wide range of soil types.
The popular kikuyu is a warm-season grass that requires at least six hours of sunlight a day to thrive. LM is tolerant of shade but not of drought and cold conditions. Cool season grasses, like Shade-Over and Evergreen Gold, are green throughout the year, but require more water.
Summer lawn care
Points to consider for a healthy lawn during the summer.
Mowing regime Cloete says do not to cut your lawn too short in hot weather. “Leave it a little taller so there is enough leaf area for the plant to transpirate and cool.”
Aim for a mowing height of 20mm to 25mm for warm season grasses and Cynodon species and 30mm for cool season lawns in sun and 50mm in the shade.
If your lawn looks whitish and takes a few days to bounce back after mowing, you are likely cutting it too short and exposing the softer parts of the leaf blade to the sun. Also check that mower blades are not blunt.
When to water Water thoroughly once a week rather than a few minutes every day. This encourages deep rooting which helps the grass cope better during periods of limited rainfall. Water in the early morning or after the sun goes down.
“Most varieties will turn pale, brown or bluish when water is needed,” says Cloete. Don’t over-water. If you have an irrigation system, turn it off during rainy periods.
Under Cape Town’s current Level 3 water restrictions, municipal water (using a bucket or watering can only) may be used for watering plants before 9am and after 6pm on Tuesdays, Thursdays and Saturdays, for one hour a day aproperty.
No hosepipes and sprinklers may be used. Use harvested rain water to irrigate your lawn.
“Grey water reuse is extremely helpful in maintaining a healthy lawn during drought and low rainfall,” says Mark Joubert of GardenResQ. “Grey water contains micro-organisms and many nutrients which are supplied to the lawn and plants.”
Never use water from sinks or dishwashers and keep grey water on your property.
If you use laundry water, change to a detergent that is biodegradable.
Never store grey water.
When to fertilise Fertilisers ensure your lawn has a good root system.
“The deeper the root system, the healthier the lawn and the deeper the roots will go to retrieve moisture in the soil,” says Cloete.
Lawns should be fertilised at intervals of between 40 and 60 days. Inorganic products are available immediately to the plant, while organic products take time to break down in the soil.
For a chemical fertiliser, Cloete suggests a 5:1:5 fertiliser which can be used in September and February and a general LAN fertiliser during the interim periods.
Remove weeds Weeds look unsightly and if left unchecked in the lawn, they may choke out turf. Use an appropriate broadleaf herbicide to control them.
Watch for problems Keep an eye out for lawn caterpillar, especially in January and February.
They live below the soil during the day and come out at night to feed on grass, leaving behind dead brown patches.
To confirm lawn caterpillar, place a damp towel on the lawn overnight and check under it in the morning. Once confirmed, treat with a biological insecticide so birds can safely eat the dead caterpillars.
Dollar spot is a fungal disease more prevalent when the weather is hot, with periods of rain. Dead patches are straw-coloured and round in shape, about 25mm to 50mm in diameter.
Brown patch is also caused by a fungus and is more common during hot, humid weather.
Both problems can be treated with an appropriate fungicide.