Lawn weeds versus lawn grasses are an ongoing struggle, perhaps more so at this time of year, especially on lawns regularly used by pedestrians, and dare I say it, vehicular traffic.

It is not obvious to most people that if a weed-free lawn of established lawn grass is the order of the day, specific needs have to be considered to obtain the end result. Such needs not only give the garden a better appearance - usually 80 percent or so of a garden is lawn - it also lowers the labour costs in both dollars and time spent. A thick sward of grass reduces weed infestation, however there are activities required to achieve the goal.

A healthy lawn is very active in the growing season and therefore creates a thick cover or sward, which ordinarily chokes out competition from weeds be they grasses or plants. However, at the first sign of weakness in the lawn, weeds will take hold, and once established can be difficult to eradicate. Cutting height, type of mower, fertiliser programme, pest and disease control and most importantly, water, are all very significant in producing a healthy lawn.

Cutting height is important for different types of grass. This is especially true of St. Augustine lawns. In Florida the height for cutting St. Augustine lawns is between three and four inches, and the final product is a thick carpet of grass with little if any weed being present. St. Augustine is a thick-bladed grass and has a prostrate habit, it fills in quickly, leaving little if any bare patches for weed infestation, especially in the summer or growing season.

From November to April when the grass can go into a dormant state if temperatures drop too low for prolonged periods of time, winter weeds can become a problem. It is therefore important to keep height of cut at least three inches. Bermuda grass can be cut on the short side or allowed to grow a little higher; I would suggest heights between a quarter of an inch to one and one half inches are best for this type of grass.

Zoysia is also a fine leaved grass, but is very wiry and needs close cutting to be at its best. Zoysia and low cut Bermuda should be cut with a reel mower, as this gives finer cleaner finish, whereas, a rotary blade can be used to cut taller Bermuda and St. Augustine lawns. Sharp blades on any mower will result in finer looking lawns and can usually give a quicker cut.

If purchasing a reel mower, remember the greater number of blades on the reel, the finer the cut obtained. This is more so on hybrid forms of Bermuda lawns, like those found on golf courses. Rotary mowers come in various engine sizes and width of cut. An important feature is to have a machine that has adjustable wheels for height of cut.

At the time of writing we are in a major drought situation, the question of cutting lawns when grasses are under stress therefore needs serious consideration. A rule of thumb is never to remove more than a third of the leaf blade at any cutting. When under stress this exercise becomes even more critical; it is better to leave uncut than induce more of a problem.

Watering a lawn at this stage of a drought situation is questionable. The ground is so compacted that run-off is always a problem, even when a natural shower occurs. Even in the best of times, how much and how often you should water is a subject of debate. Some argue that lighter watering produces a surface growing root system, while occasional heavy watering encourages roots to search for water and go deeper.

Fertilising and pest and disease control help to reduce stress on lawns and water is an important feature when looking at such programmes. Fertiliser should be of a mix to encourage strong growth and should contain minor or trace elements.

A combination of fertiliser and herbicide for weed control is also available, but the active ingredients in the herbicide should be of such a nature that they control the weeds presents in the lawn.

For spot weed control, liquid applications and herbicides are available. Always inform the sales representative as to the type of grass your lawn consists of, as St. Augustine lawns require different treatments than Bermuda grass lawns, both from the type of weed that is to be controlled, be they lawn grasses or broad leaf weeds.

The major pest problem at this time of year is Chinch Bug in St. Augustine lawns, and especially so at this time, when conditions are right for attack - hot and dry. On shallow soils, detection is difficult as the symptoms are similar to the actual insect damage, which appears as dead areas of grass moving in an outward direction.

Control is by liquid or granular chemical application. Whenever using chemicals in the garden, always read the instructions as to rate of application and weather conditions required for application. Instructions are written on the label attached to the bottle or bag and if not followed can cause damage or even death to the area being treated.

It is unfortunate but a reality that ignorance is bliss when it comes to lawn care. With most lawns starting to show stress one should discourage the trespass of vehicular traffic on any lawn area. This is true not only at this time but at any time when the exercise is to be continuous. Compaction to soil by tyre pressure will encourage weed growth in the area of compaction, and this can be seen during hot dry periods where the colour of the 'grass' under compaction is different from 'untouched' areas. When grass is under stress the activity of driving over the leaf blades alone causes additional stress.

After all, a leaf blade is comprised of cells, just imagine a car driving over your hand and what your skin would look like after a period of time.