Mow high. Set the mower blades at 3" - 3.5". Mowing high contributes enormously to the health of a lawn. Higher grass shades weed seeds and keeps them from growing; encourages a deep, extensive root development and shades the soil, helping to keep it cool and moist thereby increasing the chance of withstanding periods of drought and severe heat.
Cutting too low may create a shallow root system, thus making the turf susceptible to dying out and the roots being burned from the hot sun. Too low a cut may also provide just enough sunlight for weeds to germinate and gain a foothold.
Frequent mowing encourages the grass to expand, helping to build a thicker, heavier lawn that is more resistant to weeds and disease.
Never cut off more than one third of the blade at one time. Cutting off more may cause the grass plant to go into shock. Also, longer clippings take longer to decompose and may suffocate some grass plants. If grass is overgrown, mow twice; first at a high setting and then at a lower one.
Mow your lawn when the grass is dry, never when it is wet.
Vary your mowing pattern, cutting horizontally one week, vertically the next and diagonally the following week.
The last mowing in the fall should be short, to prevent winter damage.
Use a mulching mower that returns the grass clippings to the lawn through a continuous cut and re-cut motion. This process eventually drops the finely cut clippings back into the lawn. Mulched clippings are full of nutrients and organic matter and returns moisture to the soil.
Sharpen your mower blade at least once a year. A dull blade tears grass blades which increases the potential for disease. A sharp blade creates a clean cut on the grass, which quickly heals.
Keep blades clean. Wash the mower under deck after each mowing.
Water deeply, ensuring that the water goes down at least 4" to 6" or to the full depth of the root zone. This will require at least 2.5cm to 3.75cm (1" to 1.5") of water at each watering. Proper watering encourages deep root growth which will make the grass healthier and more drought resistant. Light watering encourages shallow root growth. These shallow roots will dry out quickly in dry, hot weather and die off from the hot sun.
Be sure the top half inch of topsoil dries out between watering. This will allow newly germinated weed seeds to die.
Water according to need rather than on a set schedule. Grass needs watering when it turns a dull, purplish colour, and does not spring back, leaving footprints, after you walk over it.
Do not over-water. Soil saturated with water will deprive the roots of oxygen, suffocating the turf. Overly wet conditions can also encourage the establishment of weeds and encourage disease.
Early morning is the ideal time for watering. Watering in the evening leaves the grass wet for a longer period, increasing the risk of disease. Do not water in the middle of the day, evaporation loss is greater.
Grass growing near large trees may need more frequent watering, because the tree roots use much of the soil water.
If using an in-ground irrigation system, make sure heads are properly adjusted to direct water towards the grass, not on the sidewalk, driveway or the road. A sprinkler head should spray large droplets of water instead of a fog or mist, which wastes water by evaporation and wind drift.