Mowing, along with watering is one of the two most important cultural practices the homeowner can do to promote a healthy lawn.
What height should you cut your lawn?
Mowing at a height of 2 ½ to 3 inches is ideal for grasses used throughout Alberta. However, many homeowners are tempted to cut a lower height to reduce the need for cutting throughout the growing season. This practice has a detrimental effect on the grass plant. The leaf blade on a grass plant is where it produces its food to sustain itself. By removing most of the leaf blade, you limit food production, which in turn decreases stolon, root and rhizome growth. By cutting too short you also remove most of the greenness from your lawn, which then gives the lawn a brownish look no matter how much you fertilize or water.
How often should it be mowed?
When mowing the lawn you should never remove more than 1/3 of the leaf blade. Example, if your lawn is 3 inches tall, don't remove more than one inch. The number of cuttings per week will change throughout the year as climatic conditions change. Generally you will mow more frequently in the spring and gradually lessen as you progress into summer and fall.
Why sharp mower blades are important
Having a sharp mower blade is very important to keeping your lawn in tiptop shape. A dull mower blade will rip or tear the tips of the grass leaving a shredded look. During the warm summer months this will cause a condition known as "tip burn" causing the tip of the blade to die back about ¼ to ½ of an inch. The condition is only temporary and will disappear within 1 to 2 cuts with a sharp blade. The shredded tip also gives disease and insects an excellent route of entry into the blade.
Grass clippings are an excellent way to return valuable nutrients to your lawn and garden. By mulching, your grass clippings will be small in size and decompose quickly. Rumors that mulching grass clippings lead to a build up of thatch are not true. Research will tell you grass clippings are mostly water, and valuable nutrients, such as nitrogen, are returned to the soil. If however the clippings are too long, leaving them on your lawn you will inhibit growth underneath. In this case bagging or raking is recommended.
Scalping a Lawn
Using a set schedule for mowing is recommended for a healthy lawn. However on occasion, the mowing gets delayed due to weather or vacation, and the grass grows too long. If the grass were to be cut at it's regular height, too much of the leaf blade would be removed. This process is commonly referred to as "scalping". Scalping causes the plant to go into a state of shock and either slows or stops growth completely. This can cause the lawn to weaken, which in turn opens the door for weeds, insects, and disease. If this happens to you, cut your lawn twice by first raising the lawn mower blade, so no more than 1/3 of the length of the blade of grass is removed. Then a couple of days later, cut again at your regular height. Good mowing practices promote a dense turf, which is your best defense against weeds, insects, and disease.