There are a number of issues that need to be addressed if your lawn is going off in summer. They can occur individually, or as an interrelation between two or more of them. The reasons have been listed in order of priority.
- Hydrophobic soils
- Fertlising & Mowing
- Beetles (pests) and fungus's
- Soil Compaction
The first cause is a retic system that is not giving adequate coverage. Likely reasons are blocked / broken/ misaligned sprinklers, change in pressure or sprinklers that have been replaced and don’t match the system. You check retic systems by finding out how many millimetres of water are being applied during each watering time. The pressure is measured by putting aerosol caps around your system and measuring the amount of water in each. If watering twice a week you need a minimum of 30mm on each day in normal conditions. These figures will let you know how long to run each station to get the required amount of water (stations may vary depending on pressure and sprinkler type). Different types of sprinklers put out vastly different amounts of water. Contrary to public perceptions, there is no time limit to how long each station runs for, as long as you water within your allocated watering day and time. Consideration must be given to drift from prevailing winds. Once you have audited your retic system and it is working satisfactorily you can look at the non wetting properties of your soil (hydrophobia).
Hydrophobic soils repel water and this doesn’t allow for even distribution of water. The water makes runnels, following down through easier penetration areas, over wetting some areas and completely missing others. This is a natural occurrence in our dry, waxy sandy soils. So, if your retic system is working efficiently and you are still having problems with a dry lawn, use a spade to cut out a square of lawn 100mm deep from the stressed area. You can then compare it with an area of healthy lawn. If it is drier, you probably have hydrophobic soil (at the same time you can check for beetles and grubs). Applying a good quality wetting agent such as Bailey’s Gro Sorb, Soil Soak, Eezi-Wet or Aqua Soak before the first heat wave and reapplying as required (we recommend 4-6 weekly in summer) will improve and even out the water penetration through your lawn.
Fertilising / Mowing
Lawn should be fertilised lightly every 6 to 8 weeks with a quality fertiliser such as Sir Walter Buffalo Fertiliser or Baileys 3.1.1 or 4.1.1. This should continue even into winter to keep your lawn green and vigorous when others have gone dormant. A tonic of iron, manganese and nitrogen sprayed on the leaf does wonders. This is available at Bunnings. It is important that your lawn is mowed at a suitable height (above 20mm and higher in shade). This helps the lawn to keep its vigour and minimises porpoising (when the runners leap over each other due to the lawn being scalped). Scalping also stresses the lawn as it doesn’t have as much surface area in the leaf to retain moisture and promote photosynthesis and it is a known fact that the length of the leaf has a direct relationship to the length of the roots (longer roots make the lawn more drought tolerant).
Beetles (Pests) and Fungus
Pests (black beetle etc) and funguses (virtually unheard of in Sir Walter but more prevalent in other buffalo types and very occasionally in the couch varieties) can also be the cause of problems with your lawn, however these add up to less than 1% of turf related problems. You can check for beetles by soaking an area of a metre square by holding the end of your hose 150mm below the surface for several minutes and seeing how many float to the top. If you get 50 or more you may have a problem and can treat with a suitable pesticide and for Velvetene lawns (ONLY APPLICABLE FOR THE VELVETENE _ DO NOT USE ON ANY OTHER LAWN VARIETY) you can apply a salt solution (1kg pool salt dissolved in 5tl water). The black beetle is not a problem if you have less than 100 to a square metre of lawn. These little creatures generally do more good than harm as they are a natural way of aerating the soil. Do not treat for black beetle unless you have an infestation of them (100/sqm). Funguses can also be treated with a suitable garden fungicide such as Fongarid or Mancozeb plus depending on the type (be aware that you do need to read the label and make sure that it is compatible with your lawn type).
Some lawns do become compacted. Like us they need air. Opening up the ground (de compacting / aerating) with a sturdy pitchfork (pushing it in and working it backwards and forwards) is one way in a small lawn or you can hire a corer from a garden hire company such as The Hire Guys. This will allow for air to circulate through the lawn and make it easier for water to penetrate.
Finally spills including fertiliser, chlorine, petrol or BBQ fat will damage the lawn. Other secondary problems can be excessive thatch, dog urine and builders slurry (lime and mortar washed out of concrete mixers etc during building). Also, all lawns have a flowering and seeding time. Buffalo lawns flower in late spring and can occur more prevalently in a new or stressed lawn. Any problems can be minimised (or even eliminated) by checking the above points and you should be well on the way to having the best lawn in the street.
THREE GROUND RULES TO A HEALTHY LAWN
Adequate water; 30mm on each of the two days allocated for watering.
Regular dusting of fertiliser
Regular mowing all year round – do not remove more then 1/3 of the leaf.