Straight Talk on Turf?EUR??,,????'??+part 1 of 3

By Dr. Van Cline

Mowers with high-dispersion discharge chutes spread clippings over a wider path, making bagging unnecessary. Recycling models make it even easier to leave clippings where they fall because they produce a finely chopped residue that?EUR??,,????'???s good for the turf.

The family of plants known as the grasses is enormous, comprising upwards of 7,500 species, but only a small number of these are suitable for what we refer to as turf. These are the species that tolerate intensive management and heavy use in places like lawns, parks, sports fields and golf courses.

Some basic information on how these turf plants grow is important background for any discussion on turf care. First, each turf species grows according to a predictable annual growth cycle. The species are divided into two general categories: cool season grasses and warm season grasses. The distinction between the two categories is based on physiological differences that have evolved through time in response to cool and warm climates.

Because the growing points of a grass plant are protected in the crown, which is located at the soil line, scalping can permanently damage turf and should be avoided. Cool-season grasses should be mown closer to two inches in height.

The cool season grasses, such as Kentucky bluegrass, perennial ryegrass, creeping bentgrass and the fescues, are adapted to cool conditions, and, as a result, grow vigorously in the spring and fall, when conditions are optimum. The cool season grasses tend to suffer through the heat of mid-summer, however.

Today's advice is to leave clippings on the lawn because they return important nutrients to the soil. However, long, wet clippings and leaves should be removed so they do not smother the grass plants beneath them.

The warm season grasses, such as bermudagrass, zoysiagrass, centipedegrass and St. Augustine, are adapted to hot climates and grow most vigorously in the high temperatures of summer. The warm season grasses are most delicate in periods of cool weather in the late fall, winter and early spring.

What?EUR??,,????'???s important about the two categories is that the timing and intensity of all turf management practices should respect the condition of a species in a particular stage of its annual growth cycle. The effectiveness of any management practice ?EUR??,,????'??? whether it?EUR??,,????'???s mowing, fertilizing, aerification or watering ?EUR??,,????'??? depends in large part on the condition of the grass plants. With that in mind, let?EUR??,,????'???s examine some ways to ensure you are properly mowing, as well as watering, the turf under your care?EUR??,,????'???

Mowing

Mowing creates a dense and uniform turf. Grass plants contain all their buds or growing points in what?EUR??,,????'???s known as the crown. The crown of the plant is located at the soil line. Grass plants grow by pushing leaves up from growing points at their base. It?EUR??,,????'???s this characteristic that allows turf plants to be cut frequently without harm. Mowing removes leaf tissue without damaging the growing points of the plant.

Is there a proper cutting height when mowing grass?

Cool season grasses have an upright growth habit. As a result, they perform best under lawn conditions at mowing heights between two and three inches. Creeping bentgrass is the exception because of its creeping or ?EUR??,,????'??stoloniferous?EUR??,,????'?? growth habit. Bentgrass can tolerate mowing heights well below one inch on golf course putting greens. The warm season grasses are predominantly creeping in growth habit, and prefer mowing heights under lawn conditions between one inch and two inches.

Am I harming the grass by cutting it too short?

Mowing is a significant stress on individual grass plants. Mowing removes photosynthetic leaf tissue, which reduces the plant?EUR??,,????'???s ability to produce energy from sunlight. As a result, no more than one-third of a turf?EUR??,,????'???s total height should be removed in a single mowing. Frequency of mowing should be based on growth rather than on the calendar. If the turf grows too much to obey the one-third rule, raise the mowing height, give the turf a chance to recover for a few days after mowing, then lower the height to the preferred setting and mow again.

Rooting depth is directly related to turf canopy height. In general, the longer the height of cut the deeper the root system. A deep root system is generally associated with a healthier, more stress-resistant turf. Therefore, mowing at the upper end of a species mowing range is generally preferred over the lower end.

Additional tips: Because the growing points of a grass plant are protected in the crown, scalping can permanently damage turf and should be avoided. Also, lawn weeds are generally more competitive when turf is cut short. Therefore, mowing at higher heights of cut can reduce the incidence of many weeds simply by shading them out.

No more than one-third of a turf?EUR??,,????'???s total height should be removed in a single mowing. If turf grows too much to obey the one-third rule, raise the mowing height, give the turf a chance to recover for a few days, then lower the height to the preferred setting and mow again.

Does grass mind if I mow it in the same pattern every time?

Turf species with creeping growth habits (bentgrass and most of the warm season species) can develop what?EUR??,,????'???s known as ?EUR??,,????'??grain,?EUR??,,????'?? where the leaves and stems grow in one direction. Changing mowing patterns is one way to reduce grain. Cool season species with more upright growth habits are less likely to develop grain. Changing mowing patterns is less important, as a result. Alternating mowing directions or developing other creative mowing patterns can produce an attractive striping effect in turf, giving the homeowner or landscape contractor a chance to display some artistry in the same way that baseball fields or golf course fairways are striped!

Is it better to remove or recycle grass clippings?

Today?EUR??,,????'???s advice (contrary to what was recommended in the past) is to leave clippings on the lawn. The old belief that clippings contribute to thatch is inaccurate. Clippings actually decompose quickly under normal conditions. Thatch is a spongy accumulation of roots and stems at the soil surface. Clippings returned to the turf do not contribute to thatch in a significant way. Leaving clippings on the lawn reduces environmental waste, saves the labor of collecting and composting them, and reduces the amount of fertilizer required, since the clippings return nutrients to the soil as they decompose. Research has estimated that 20 to 30 percent of the fertilizer applied to a lawn is removed and discarded if clippings are removed. That represents a significant savings.

Some of today?EUR??,,????'???s new mowers include high-dispersion discharge chutes that spread clippings over a wider path, making bagging unnecessary. In addition, new recycling mowers make it even easier to leave clippings where they fall. They cut each grass blade several times, producing a finely chopped organic residue that is then forced back into the turf. When shopping for a mulching mower, make sure you are getting the real thing. Some manufacturers simply block off the clipping exit areas in the deck and call it a mulching machine. True mulching mowers feature a closed deck design and other unique features, such as a special blade, front throw chamber and/or baffles on the underside of the deck.

There are situations when you should not leave clippings on the lawn. If you have been unable to mow for a long period or must mow in wet conditions, the long clippings are likely to form heavy, soggy clumps that cover the grass. In such cases, remove the clippings so they do not smother the grass plants beneath them.