Revitalise Your Lawn
If you have a lawn, you probably know it needs maintenance, but what exactly are your lawn’s maintenance requirements?
There are four broad groups of problems you might encounter with a lawn:
1. Nutritional
Either too little or too much of a particular nutrient.
2. Environmental
The conditions of the air and or soil environment are having some detrimental effect on the turf varieties.
3. Pests and Diseases
Some other animal or plant growth (often microscopic) is damaging the turf.
4. Weeds
Plant growth which competes with the turf for water and nutrients.
Nutritional Problems
Nitrogen deficiency symptoms: yellowing of the leaf blades. Older leaves go yellow first, stalks become slender and weak.
Remedy: If badly drained area then install drain, otherwise feed sulphate of ammonia.
Phosphorus deficiency symptoms: purplish tints on leaf blades.
Remedy: super-phosphate at the rate of 250 gms per 100 sq. metres.
Environmental Problems
Dry Patch: Caused by soil compaction leading to poor water penetration and subsequent drying out. It shows up as large irregular areas of brownish, discoloured grass with localized spots of extreme dryness. Usually some form of aeration is the recommended remedy.
Heat Scald or Scorch: Here a thick mat of roots of trees or shrubs prevents the turf roots from penetrating very deep. This root mat can absorb a lot of water in hot weather which can heat up very quickly resulting in scalding the turf roots. The grass will look scalded or scorched becoming brown first the later black. Scarifying which is a mechanical method of thinning out the root mat, is practiced as a remedy.
Mechanical Injury: Mowing turf too close will result in a patch of dead or burnt grass. Turning machinery too quickly or sharply can pull out grass or bruise it. A hose left lying on a part of a lawn will cause the grass under it to yellow.
Tree Roots: If turf is watered frequently but lightly only the top inch or so of soil is moist. Tree roots in this situation will come to the surface pushing lumps in the lawn and competing with the grass for food and nutrients. These roots can be cut out, but unless the watering is occasionally heavier in the future the problem will be recurring.
Pests and Diseases
Crickets and locusts feed on foliage: Leaves are obviously being eaten. Control with a spray of rogor.
Brown Patch: Yellow to brown patches appear approximately 1 metre diameter, occurs in hot weather on badly drained turf. Reduce watering and spray with a fungicide (e.g. Benomyl). There are many other fungus problems with similar affects which are all treated similarly, for example, Dollar Spot - eventually can get a white cobweb affect on grass; Fairy rings - circles of affected grass (grass in centre still OK).
Rust: Another fungal problem where orange dots or streaks appears on leaves. Spray with Zineb.
Removing Weeds
Most types of grass grow slowly in winter, giving weeds the opportunity to grow strongly. If you only have a few weeds, dig them out with a hand weeder (e.g. a two-pronged weeding fork). For more severe weed problems, spot spray with glyphosate or, if the grass is growing actively, use a special lawn weed/feed spray that won’t harm the lawn grasses.
Replant with seed or turf as soon as the weeds die off, otherwise they’ll simply take over again.
If thatch is a problem, remove it before you spray the weeds (see below for instructions). Planting new grass over the top will simply perpetuate the problem.
Lawn Renovation
Winter can be a good time to repair the lawn. You are less likely to be using the lawn over winter, so the lawn renovations are less likely to be an inconvenience.
What do you do to renovate a lawn? The three most important steps in renovating a lawn are:
- Getting rid of the weeds.
- Aerating the soil to improve water and air penetration.
- Establishing lawn grasses in the bare spots.
Aerating the Soil
Many lawn problems are caused by soil compaction, as people and vehicles repeatedly move over the lawn. Wet soils are especially prone to compaction.
For small lawns, use a garden fork to aerate the soil. Work the fork backwards and forwards at approx. 10 cm intervals to open up the soil.
On larger lawns, a coring machine will do the job quickly and thoroughly. The coring machine removes small plugs of soil, leaving them on the surface of the soil. These machines can be readily hired from tool hire companies.The holes can then be filled with topdressing soil or coarse sand.
In severely compacted or contaminated soils, it may be necessary to lift the turf and replace the sub soil, before replanting.
Re-establishing Lawn Grasses
Spot treatments: Once you’ve got rid of weeds and thatch, rake the soil evenly (top up the soil first if necessary) and spread seed over the bare patches. Alternatively plant runners or lay rolls of turf.
What is Thatch?
A layer of old, dead runners under the turf, a thick layer of thatch will feel spongy underfoot and prevent water, air and fertiliser penetrating the soil.Kikuyu, Buffalo and Queensland Blue grasses are especially prone to thatching.
Thatching
If thatch has built up too much, cut the lawn closely and rake it severely with a steel rake. You may need to mow and scarify it several times, until there is a bare cover of grass.
A mechanical de-thatcher can be hired to do the job, or hire a lawn specialist with a de-thatcher. Fertilise and water the lawn afterwards to help it quickly recover. Note: This is best done when the grass will recover quickly – late winter in cooler areas.
Liming the Soil
Poor lawn growth can be a result of acid soils. Some soils are naturally acid, while others become acid through the repeated use of lawn fertilisers that contain sulphate of ammonia. A dressing of lime or dolomite during winter will help to reduce acidity. Apply at the recommended rate, as too much lime encourages clover and other weeds to flourish.
For more information on lawn renovation go to:
Or why not do a course on turf care?
Turf care:
Turf repair and renovation:
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