Nearly all turf professionals deal with the task of maintaining high-quality turf. But as a golf course superintendent, the standards for a quality cut are exceedingly strict. A wide variety of factors contribute to an acceptable appearance after mowing. Some of these are agronomic-related and you can eliminate or avoid them by adhering to the appropriate cultural practices for the location and type of cultivar growing there. However, many other quality factors are dependent upon the type of mowing equipment you are using as well as your maintenance program for this equipment. Eliminating deficiencies in these areas can lead to enhanced quality of cut, improved turf health and better playing conditions.
Turf conditions play a dramatic role in turf's appearance after mowing. You must always consider turf conditions before attempting to remedy a problem with adjustments to your turf equipment. Equipment used strictly for mowing cannot remedy turf conditions but, oftentimes, you can adjust this equipment to adapt to a given turf condition.
The goal of a turf equipment service person is to help address concerns by matching the equipment to the current conditions. This is a partnership between you and those persons responsible for the turf. The ultimate solution is usually a combination of turf remedies and machine adjustments.
It is important to remember that the same cutting unit setup will not work for every turf condition; nor will it work every time in what seems to be identical conditions. Requirements are different between warm-season and cool-season grasses. Cutting units should be set up for the grass type and seasonal differences.
An incorrect cutting unit setup can cause you more problems than it can resolve. You should check the items listed below, correct them if necessary, and try to ensure that setup is identical on all cutting units used on multi-cutting-unit machines.
Adjusters, pivots, bushings and compensating springs: Lubricate if necessary, and check to ensure they are tight and in good working order.
Bedknife: Correct for the application with sharp, flat and straight cutting edge.
Bedknife attitude: Set to manufacturer recommendations.
Bedknife contact: Set properly according to manufacturer recommendations.
Reel: Make sure it has a sharp cutting edge (relief or backgrind recommended) with less than 0.002 (0.05mm) run out as a general rule of thumb. Always refer to manufacturer recommendations.
Reel bearings: Check to see that these are in good condition, have no end-play and are adjusted properly.
Reel diameter: This should meet or exceed the manufacturer-recommended minimum diameter.
Rollers: These should be parallel to the reel (see operator's manual).
Roller condition: Check bearings (no end-play). The surface run-out, as a general rule, should be less than 0.015 (0.38mm) (but always refer to manufacturer recommendations), and bearing should be centered in the frame.
Height of cut (HOC): Set mower to obtain the correct effective HOC. Remember that the effective HOC can differ from the bench setting due to several factors including the weight of the cutting unit, rollers, bedknife attitude and turf conditions.
The wear factors must be equal. If you have a new part on one unit and the same part is worn on another unit, it can cause a difference in cut.
Define the issue. You must clearly understand and define the problem before you can begin to address it correctly.
Evaluate turf conditions for their part in the outcome (e.g., extremely wet or dry, recent turf maintenance performed such as top dressing, extreme heat or cool temperatures, etc.).
Verify that the traction unit is operating properly and is in good condition (switches functional, proper RPM, maintenance is up to date, etc).
Check the cutting units for accurate and proper setup.
While attempting to increase the quality of cut and resolve turf appearance issues, it is necessary to make physical changes to components of the cutting unit or traction unit. You should make all adjustment, changes and modifications from a current condition singularly, using a scientific process. Make only one change at a time and take careful notes of the conditions resulting from each change before making additional changes or adjustments. Making multiple changes to a cutting unit at one time will result in the inability to identify which adjustment or setting resulted in the improvement or worsened result. A systematic approach to troubleshooting will assist you in resolving issues timely and effectively.
What follows are some types of poor-quality cut and possible corrective tips. Although the tips listed are observed individually, the ultimate solution to the problem could be a combination of two or more corrective actions.
Description: The discharge from the cutting unit should be spread evenly over the turf. The discharge collecting and dropping in clumps on the turf is referred to as clumping.
Some causes and corrective tips for uneven dispersion:
Cutting off too much grass at one time. Mow more frequently
Mowing while grass is damp. If possible, allow turf to dry out prior to mowing
Grass collecting on rollers. Use powered rear-roller brushes or scrapers
Description: Rocking movement of the cutting unit that leaves an unacceptable wave-like appearance. This could be caused by all or one of the cutting units. Color variations may be present. The appearance of light and dark patches could be an indication of bobbing. You can usually identify this pattern by observing that the wave tips are approximately six to eight inches tip to tip.
Note: Change mowing direction 90 degrees. If the pattern follows the mowing direction, it is bobbing. If it does not, the pattern is most likely due to turf variations.
Some causes and corrective tips for bobbing:
Inconsistent turf density. If pattern matches turf density changes, then apply turf remedy to gain consistent density (dethatch, verticut and aerate).
Grass build up on roller. Use scrapers or brushes to clean rollers.
Cutting unit weight bias (not using or misadjusting turf compensation system). Use (or adjust) turf compensation springs.
Counterbalance/down pressure set wrong (too light on ground). Adjust counterbalance/down pressure for more weight on turf.
Out of round rollers. Verify roller condition.
Excessive mowing speed. Slow down.
Description: An unacceptable wave pattern on the surface of mowed turfgrass. You can identify this problem if you notice that the wave tips are two or less inches, tip to tip. The clip and the HOC, as a rule of thumb, should be approximately the same, but can be varied to achieve specific results.
Some causes and corrective tips for clip marks:
Ground speed is too fast for the reel speed. Decrease ground speed.
The reel speed is too slow for ground speed. Increase reel speed.
HOC is too low for the number of cutting unit blades. Verify the proper cutting unit configuration and number of blades for the application.
Description: The tendency for turfgrass or its runners to grow horizontally. Horizontal growth can also be the result of recurring weather, water flow, wind and sunlight direction. Some cultivars (i.e., bentgrasses and bermudagrasses) tend to naturally grow horizontally.
Some causes and corrective tips for grain:
Note: When addressing issues of excessive grain, remember that the appearance may worsen initially, then gradually improve with continued mowing.
Not alternating mowing direction. Establish a pattern of mowing that changes direction regularly. The more random the directions change, the better. Circle cutting.
Turf conditioning or maintenance is incomplete. Dethatch, verti-cut and aerate.
Inconsistent turf density or texture. Using groomers, brushes and combs may prove helpful.
Description: Cutting units running side by side cut at different heights. The cutting units on one line cut at a different effective HOC than cutting units on another line. In another case, one cutting unit appears to be cutting lower on one side while all other points appear equal in height.
Some causes and corrective tips for mismatch:
HOC is set different from one end of the cutting unit to the other. Verify all HOC settings within 0.005 (0.12mm) of each other.
Rollers are not parallel to the reel and to each other (vertical and horizontal). Verify that rollers are paralleled prior to setting HOC.
Weight distribution of cutting unit is uneven. Ensure that weight is distributed evenly. Set counterbalance adjustment to obtain consistent effective HOC over all cutting units. This can be different for each cutting unit. Make sure that the reel motor hoses are not hindering free rotation of the cutting unit. Hoses should be free of twists and tight bends.
Description: The area of overlap is that area where cutting units mow over the path of other cutting units. This is either individual cutting units within the path of a machine or where those paths meet (up and back). The grass is rolled or cut at least twice within this area. Various color variations can appear.
Some causes and corrective tips for overlap marks:
The effects of being rolled twice usually create raised or darker marks in turf. These marks should dissipate within a few hours after mowing. Use rollers with different end designs (shouldered rollers).
Excessive thatch or grain. Dethatch, verti-cut, aerate.
Dull cutting units. Sharpen reel and bedknife.
Description: Scattered uncut grass blades throughout the cutting unit path. The uncut blades stand above the general line of the effective HOC. Cutting unit sharpness, adjustment, clip-versus-grass length, resiliency of grass and bedknife attitude are the key factors affecting this condition.
Frayed leaves from poor cutting efficiency can have the same effect.
Some causes and corrective tips for stragglers:
Dull cutting edges (reel and bedknife). Sharpen cutting unit (bedknife and reel).
Bedknife adjustment is incorrect. Adjust bedknife (light contact is preferred).
Cutting unit is out of clip range (driving too fast for the reel speed or the reel speed is too fast for HOC). Increase/decrease forward speed or increase/decrease reel speed.
Description: A line of taller grass that has not been cut. Single streaks are the result of a bent or nicked bedknife. Multiple streaks are more often the result of rifling due to heavy contact between the reels and bedknife. Streaks may also occur where a tire rolls down an area before it is cut or where grass passes uncut between adjacent cutting units.
Some causes and corrective tips for streaks:
Damaged bedknife (picking up objects, such as spikes). Beware of objects that could get caught in the reel. Check area to be mowed for foreign objects prior to mowing.
Rifled bedknife or reel (uneven wear). Repair or replace damaged reel and bedknife (regrind if necessary).
Turing too sharply or cutting on side hills where the rear of the machine can shift over to the downhill direction. Change mowing direction or pin the cutting units in the straight position.
Avoiding poor turf appearance involves several aspects of turf and mower maintenance. This guide addresses some of the most common causes and offers corrective tips to remedy turf or machine deficiencies. Being able to identify the cause and implement the right solution will result in high-quality cut on your manicured turf.
Tony Ferguson is senior marketing manager for The Toro Co. (Bloomington, Minn.).
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