Mowing the lawn appears to be a simple task. You simply start the mower, yank the cord, and walk or ride around the yard for a while. But, as any lawn expert will tell you, there's a lot more to it than that. How you mow, when you mow, and what you do with the clippings all have an impact on how well your lawn performs. Mowing the lawn is, in fact, the most undervalued and overlooked aspect of good lawn care.
It all starts with grass height
Cutting grass too short is the most common mowing blunder made by the average homeowner.
This is a bad idea for several reasons:
- As the grass tries to recover from near-total decapitation, it increases moisture and nutrient demands.
- It reduces the amount of chlorophyll available for the grass roots to produce energy. (Longer blades indicate that there is more chlorophyll per grass plant, resulting in more vigorous grass.)
- It allows the soil to dry out faster, which increases the negative effects of drought.
- When taller grass blades aren't shading them out, weeds germinate better and get off to a faster start.
What makes a mown lawn look good is the evenness of the cut — not its height. Most people are just as happy with a 3-inch-tall evenly cut lawn as a 1-inch-tall evenly cut lawn.
The theory that cutting short lengthens the time between cuts also doesn’t hold up. Grass grows faster after it’s been cut short as it tries to rebuild itself to its genetic norm.
A good in-season height for most turfgrasses is 2½ to 3 inches — typically the highest setting on mowers. The exception is toward the end of the season when it makes sense to cut a little shorter so the grass blades will dry faster over winter. That can help head off early-spring fungal problems such as snow mold.
Don’t wait too long between mows
A second important issue is how often to mow. A good rule of thumb is to mow the lawn often enough so you’re never removing more than one-third of the blade length at a time.
Mowing is pruning. And that’s a form of injury to the grass plants. Severe cutbacks are much more stressful on grass than lighter cuts and require more energy to heal.
When grass is growing fastest in mid-spring, this may mean mowing twice a week or every four or five days. It’s much better to cut that often than to wait a few more days and end up having to whack 3 inches off of a 6-inch stand. That’s not only a shock to the grass but creates an unusually large mass of clippings.
What to do with grass clippings?
Big piles of clippings are bad news because they can’t be left on the lawn. They’ll mat down the living grass blades and shut off the sun’s rays, which will yellow the grass and encourage diseases. Clippings that can be seen even in small piles should be raked up and preferably composted or used as a mulch over garden beds.
Clippings can provide one-third of your lawn’s Nitrogen needs
If you’re mowing regularly, clippings won’t be a problem. They’ll be short enough to disappear into the lawn. It’s best to let the clippings drop into the lawn as opposed to bagging them. Why?
- As they decompose, they return valuable nutrients to the lawn soil. According to Penn State University turfgrass researchers, allowing the clippings to decay in place provides about one-third of the lawn's total nitrogen needs for the season.
- The decaying clippings enrich the soil with organic matter.
- Keeps organic “waste” out of the trash stream.
Mulching mowers do an excellent job of chopping the clippings into small pieces. Even ordinary side-discharge mowers disperse clippings well enough to let them lie when you mow at frequent enough intervals.
If you fall behind, at least try to work around the perimeter of the yard, shooting the clips inward so you’ll end up having to rake only one or two channels in the middle.
Avoid cutting the grass when it’s wet. The clippings are more likely to mat together then, you won’t get an even cut (the mower wheels will flatten grass blades), and you may even compact the soil if it’s wet.
Also, don’t attempt to mow when the grass is going brown and dormant in a drought – even if you’re mainly doing it because weeds are continuing to grow and are poking up. Grass crowns become brittle and fragile in drought conditions, and if you smash them with your feet and mower wheels, the plants won’t recover when rains return. Dead crowns equal dead grass.
Lawnmower types and blades
Some people swear by their reel mowers — the ones with the old-fashioned bladed drums that go around and snip off grass blades like scissors. These work great, but so do rotary mowers when they’re kept in good condition.
No matter which style of mower you’re using, the most important thing you can do is keep the blades sharp. Nice, sharp lawn mower blades make a clean cut. Dull blades rip the heads off grass blades and cause ragged edges.
Rough, ragged cuts make bigger openings that turn brown and stand out more than sharp cuts. But even worse, those bigger openings cause the grass to lose more moisture, which increases drought stress in hot weather. And bigger openings leave grass blades more vulnerable to disease spores.
Sharpening your lawnmower blades once every few years is not enough. Two or three times during the growing season is a better game plan. Some homeowners own two different lawn mower blades so they always have one for the mower while the other is being sharpened.
Habits and mowing patterns
Finally, there’s the issue of the course you take as you mow. Many homeowners take the same route every time because it makes sense to them for one reason or another (convenience, habit, avoiding the nosy neighbor, etc.) There’s no horticultural problem with that, but altering the route can make a cosmetic difference.
Look closely and you’ll notice that the color of the grass appears different depending on which way you passed over it with the mower. That’s because the force of the spinning mower blades blows the grass blades as it cuts them. Light-reflecting off the grass will make it look lighter or darker, depending on which way the blades are laying.
It’s this pattern of mowing that accounts for the designs commonly seen on athletic fields. Some avid home-lawn fans do the same thing themselves, and there are even special mower blades designed for creating patterns.
Varying your route can make a slight difference in the evenness of the cut by making sure no particular areas keep getting pushed down while others are always cut off.
Lawn mowing might not be rocket science, but it isn’t exactly foolproof either. Just remember these few key rules, and you’ll be master of your mower: Mow high and often. Let those clips lie. And keep those lawn mower blades sharp!
Now that you know how to mow, be sure to use the best lawn care products from GreenView.