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Grass #4 of 4
by Dan Clost
by Dan Clost

email: dan.clost@sympatico.ca

First serious garden earned 25 cents from the Kemptville Horticultural Society when I was 12. Have been poor in horticulture ever since but rich in spirit.

Went to work writing the Good Earth column (over 500 articles published in newspaper, magazine, website and journal.) and learned that what was printed wasn't what I wanted to say and certainly not what Gentle Reader understood me to say. Subsequently have developed a certain clarity and economy of words.

Day job- nursery and production manager for a large nursery/garden centre
Side job- Garden restoration and renovations, design consultations, remedial pruning.
Night job- garden writer and communicator (overnight success in another 20 years)

Dan gardens in Canadian Zone 5b


August 11, 2002

We're almost finished with lawns. This week we'll discuss mower blade sharpness and direction of cut. It is sort of boring but it would be a shame to have all your hard work go for naught because of a few overlooked technical bits.

Before we get into that let's take a moment to look at grubs and unseen crawly things under the ground. Are bits and pieces of your lawn dieing out for no apparent reason? Are some of the dead splotches similar to the urine circles caused by dogs- and you don't have one? Does your front yard look like a minefield from skunks digging? If the answer is yes, the cause is likely one of several types of grubs. Unfortunately, treatment now is not recommended unless the devastation is considerable and you have decided to replace the whole carpet. For now, repair the small patches with a bit of topsoil worked into the spot and then seed it. Remember to keep these patches moist. For the rest of us, we want to wait until July when the adults lay their eggs in the ground to start the cycle over again. That's when the little devils are most vulnerable. Come the end of June, we'll spend a little time with these odious pests. (Given the recent "Hudson" ruling look for major changes across the country in regards to chemical intervention in the green industry.)

With the rain finally here we can expect a spurt of growth with our grass which means we'll be out there cutting possibly every fourth day or so. We've already established our preferred heights of 2.5" to 3". When to cut is equally important. Cutting grass involves time and money so we want to be both prudent and efficient. The general rule of thumb is to never cut more than 1/3 of the blade at any one mowing. The greater amount removed, the greater the shock; the 1/3 rule is a good compromise. If you have a 3" lawn, don't let it grow past the 4" mark. If you have a 2.5", then a tad under 3.5" is the longest. (Oops, forgot the metric; 6 cm height is cut at 8 cm and 7.4 cm is cut at 10 cm, approximately.)

Sharpness of the blade is rather important. We can easily figure out that a dull blade will not slice through as nicely as a sharp one. But here is what happens to the grass itself. Firstly, the tip of the blade will be torn off leaving a jagged wound. Secondly, the portion just below the cut will be bruised and crushed. The plant now has a much longer cut to mend and, due to the internal damage, it will experience some difficulty doing so. The biological result is a monocultured area that is weakened and susceptible to pests, diseases and environmental stresses. It's like hanging out a big neon sign inviting trouble. The visual result is an uneven surface covered with brown tips.

We change the direction of mowing for the same reason. Grass, if continually cut in one direction, will bend over, forming a grain. Grounds keepers at baseball parks will cultivate this bent to favour the home team. (Two bad puns but my brother-in-law really likes them). Golfers spend a long time on the putting greens looking at the direction of cut as much as looking for the slope. Mind you, these are intense management situations. When we cause a grain to develop in our home lawns, the mower blade will actually bruise and tear the grass blade before it cuts off the tip. (See the above paragraph for effects.) So, one week, cut in one pattern, i.e., back to front, and next time cut side to side. Next time, switch to the diagonal. An added benefit is that this pattern draws the eye along the new "length" making it appear "longer."

That's it for lawns.

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