Mowing is a cultural practice necessary for a quality turfgrass. Regular mowing will help develop colour, density, texture, root development and wear tolerance. Following are some useful tips to help develop a uniform turf sward:
Prior to mowing, debris such as rocks, sticks etc. should be removed from the turf area. This not only reduces the damage caused to mower blades and bed knife (cylinder mowers) it may also prevent serious injury as mowers can throw solid objects considerable distances.
Mow when the turf is dry, it cuts more easily, doses not clog up the mower, gives a finer appearance and requires less time to cut. Mowing when wet dulls the mower blade quicker, can leave clumps of grass on the surface which may kill the mown turf undereath and assists in the spread of disease - mowing wet grass should be avoided altogether.
The mowing pattern or direction should be regularly changed. This will prevent rutting of the turf suface, wheel marks or lines (which are not "stripes") and soil compaction from machinery. Changing the direction of cut will also mean that the turfgrass does not lay flat or produce excessive grain. Mowing aginst the grain, if present, can cause significant scalping.
Mowers should be maintained in good working order and blades kept sharp. Turfgrass vigour, quality and leaf growth are impaired if the turf is mowed with a dull, improperly adjusted mower. Poorly maintained mowers can be a dangerous source of personal injury. Appropriate footwear and other recommended safety equipment (PPE) should be used when mowing.
The cutting height usually depends on the type (species and variety) of grass, its intended use, whether it is in full sun or shade, and the season of the year. In general, the finer leaf grasses such as green couch perform best when regularly mowed 20 mm to 30 mm or lower. Other, warm-season grasses (broad leaf varieties), such as sweet smothergrass, buffalo grass, and broadleaf carpet grass prefer a higher cut of about 30 mm to 50 mm. It should be noted that the shorter a turf is mowed the more often it must be mowed to maintain an acceptable turf quality and to help prevent scalping.
The frequency of mowing depends on the growth rate of the turfgrass, season and what inputs you have been applying e.g. water and fertiliser. A rule of thumb is to NOT remove more than one-third (1/3) of the leaf area per mowing as this stresses the turf plant and prolongs recovery e.g. if you current height is 30 mm, only take a maximum of 10 mm off the sward height.
Grasses growing in shady areas should be cut 30% to 50% higher to help maintain the leaf surface needed to carry on photosynthesis. Similarly to managing shady areas, it is advantageous to raise the mowing height during prolonged periods of drought stress and after prolonged wet, rainy periods. For grasses that are in full sun, or sports turf, do not raise the cutting height between summer and winter. The only time the height should be adjusted is when the field is being prepared and utilised for multi-use sport e.g. transition from AFL to cricket.
Usually, the higher the cut, the deeper the root system. Low cut lawns have shallower root systems, which leave the plant susceptible to wilt and stress on hot dry days. Shallower root systems require more frequent watering leading to an increase.
It is important to regularly check the sharpness of the mower blades. A frequently seen symptom of dull blades is “feathering” or tearing of cut leaves. The surface area of the cut is greatly increased and the tissue is often crushed, increasing tip browning, the entry of disease and plant water loss, as well as reducing the overall uniformity of the lawn surface. For a better looking lawn, aim to keep blades sharp for a straight clean cut that seals quickly. It may be best to have someone undertake sharpening for you. Anually prior to spring is a good idea.
The rotary-type mower cuts by the impact of a knife blade operated in a horizontal plane. It causes a certain amount of mutilation and injury to the leaf blade at the point of impact. The rotary mower can be used to cut taller grass and weeds and can mulch fallen leaves. Scalping can be a problem with rotary mowers when the turf surface is uneven.
The cylinder guides the grass leaves against the bottom blade (bed knife). The bed knife is the actual cutting blade and should be maintained and sharpened regularly. The cutting action of the cylinder against the bed knife results in a scissors-type effect. Cylinder mowers require a relatively smooth surface for effective operating. The cylinder mower is preferred and more effective when regular close cutting occurs and a dense turf sward is required. Cylinder mowers can be more costly to run than rotary types, as the cylinder requires specialist machine sharpening.
Mulching mowers tend to cut grass into finer pieces allowing it to filter down among the existing grass leaf. Use a catcher when weed seeds are prevalent or when excess grass is rolling up behind the mower.
Content included on this page has been modified; original content was published in Lawns and Lawn Care, a homeowner’s guide (no date) and on the web by the former Dept of Primary Industries and Fisheries. Permission for use has been granted by the now Dept of Agriculture and Fisheries.