Cup cutters to the rescue!
Our long-time greens-keeper, Alberto Aguiar, strode past my office window with a stern expression on his face. He was headed for the tool room. After 16 years, I knew this look. He had an unexpected problem.
When he came out, he was carrying two cup cutters and a topdressing blade (similar to a metal squee-gee). This indicated that the trouble was on a green.
I went to the door and asked, "Something wrong, Alberto?"
He described how a coyote had been digging in the middle of the No. 1 green. "Must be a dead mouse or something in the drain pipe," he explained.
"Can the damage be moved?" I asked.
"I think so." He said, "It looks like the damage is only about 3 or 4 inches wide. I'll let you know if it's worse."
His damage estimate was encouraging. Because we operate a low-end, low-green-fee course, unexpected expenses can put a real dent in our maintenance budget. To deal with such problems in a low-cost way, we've developed some repair methods that don't tie up much manpower or equipment. One of these is the use of two cup cutters to move small bad spots in a putting green out to edge areas where they won't affect play.
Fixing the damage A golf cup is 4.25 inches in diameter. If the damage to the green is smaller than that, repair is simple. Use one cup cutter to cut a cup hole directly over the damaged area. With the other cup cutter, take a fresh, 10-inch-deep plug with healthy turf from the edge of the green, close to the collar. (It's best to do this on the high side of the green.)
Next, you simply switch the locations of the two plugs. First, put the new, fresh plug in the hole where the damage was. Then, place the damaged plug at the edge of the green. Using the same sand with which the greens are regularly dressed, lightly sand the new plug location and work the sand into the turf with a broom or some similar tool.
Apply a generous amount of sand on the location of the old, damaged plug. Be sure to level the sand in the damaged area of the plug. If most of the plug's surface has lost grass, use a weeding knife to steal a 1- or 2-inch turf plug from a fresh place near the green collar. Insert this small plug in the center of the damaged area. Fill any small holes with topdressing sand and tap it down.
A one-plug repair procedure like this only takes about 5 minutes. It removes unsightly damage from a location where it could affect play and moves it almost completely off the green. Then, near the collar, the damaged section can fill in quickly and will experience little traffic. The chance that the new edge location will seriously interfere with a golfer's shot is remote.
As described, you can use a broom to work sand into the turf or you can build a tool specifically for this purpose. For example, take an ordinary steel angle iron, with 1.5-inch legs, 1/8-inch thick and about 2 feet long. Weld this to the shaft of a broken hoe, rake or similar garden tool. The edges of the steel angle iron will quickly acquire a smooth, curved surface that glides over the turf and guides the sand into the spaces between turf blades. You can use the 4-foot and 6-foot-wide aluminum blades on the back of landscape rakes for topdressing large undamaged areas, but a short steel blade does a better job for spot repairs.
The "two-cup-cutter repair" technique, when you can use it, has several advantages over patching with cut sod. For one, it's fast and doesn't disrupt play for more than 2 or 3 minutes. Second, you can easily take up to a full 10-inch deep section of the green's root-zone material and accurately switch the repair core between the two locations. Doing so will not adversely affect the root-growing medium. In addition, the repaired spot is no more noticeable than an old cup location, which golfers are used to seeing on the greens. Best of all, the turf in the repair plug has the same grooming and local environment as the surrounding turf. It will quickly blend with its new neighbors.
Because this last advantage is so beneficial, you should consider using the two-cup-cutter repair technique even when the damage exceeds the area of one-cup diameter. For example, if the damaged area is 2 or 3 feet long, but not more than 4 inches wide, you can make a series of plug removals and replacements. You can easily take one dozen or more cores from the high edge of the green. Leave at least 6 inches of healthy turf between these plug cuts to maintain the vigor of the turf that must grow in to heal the old plugs.
When the damaged area is too large for the two-cup-cutter technique, you can use hexagonal-shaped cutting tools. Several golf-supply companies sell these tools. Sod patches cut by these hex tools fit and lock together well and cover large areas with no open soil spaces.
However, more care is required with the sod-patch methods for several reasons:
*You must bring in the turf from an outside source, such as a nursery green on the golf-course property or a turfgrass producer at a more distant location.
*When using sod, you must be sure that the repair turf and the soil in which it is growing are compatible with the turf and root-zone material of the damaged putting green.
*The sod must be mowed at exactly the same height as the putting green in which you place it. Failure to do so may cause long-term color and textural differences.
*Roots on purchased turf or turf cut from a nursery green will not be as thick or as long as the 10-inch deep section taken by a cup cutter. The depth of cut sod is ordinarily less than 2 inches. It usually does not include all of the established root mass.
For that reason, you need special skill to prepare the compacted soil surface on which you'll place the replacement sod.
*The repaired playing surface must be at the identical level of the existing mowed surface. You must take great care to avoid scalping high spots with a mower or forming water-collecting depressions. When you mow a bentgrass putting green at 1/8 inch, a sod-placement-height error of 1/16 inch can affect play and appearance for weeks.
So far, we've discussed simple damage to the putting green and damage of limited extent, both in area and in depth. Of course, many more causes of severe putting green damage exist, even if we exclude environmental conditions such as drought, insects, disease, weeds and other problems.
When inspecting damage to golf greens, it is essential to consider the entire depth of the green structure. Damage can involve issues other than the playing surface of the turf. Two additional culprits are compaction and the contamination of the root zone by foreign materials.
"Compact" problems are no small matter Most superintendents have had to deal with compaction caused by the use of heavy equipment. But, what about the unexpected problems caused by horses, deer or other livestock wandering on your putting surfaces? These animals can cause substantial compaction damage. For example, a horse's hoof can apply an impact load of half a ton on a 6-inch circle. Such compaction can damage the root zone worse than it does the turf surface, particularly if rain or irrigation has just occurred. In these cases, don't be content with merely lifting the surface turf and restoring the level appearance of the grass. You also must investigate the subsurface compaction.
To do so, use a standard 16-inch coring tool to examine the material under the center of the hoof-print (or wheel mark, if you've had vehicles riding over your course). Compare this damaged section to a similar core taken in an adjacent undamaged area. If you find a significant increase in compaction over the top 6 inches of the core, you should remove the soil under the damage imprint and replace it with non-compacted material. Once again, you can use the two-cup-cutter technique.
Damage from foreign materials Damage from foreign materials--such as oil and fuel spills, chemicals and the blood, urine or feces of animals affect the root-zone as well as the surface of the turf. If the contaminant is a large quantity of non-soluble liquid such as oil or fuel, you'll typically need to remove the damaged grass plants and all traces of contaminated soil in the root-zone. This can extend to the full depth of the USGA-type 14-inch root-zone layer. Then, immediately begin repair procedures. Any delay will give the contaminant more time to penetrate the ground and spread. Again, two major concerns will be re-establishing the level putting surface and matching the compaction condition of the existing undamaged green structure.
If the contaminant is water-soluble, such as animal urine or similar waste, an immediate and thorough flushing with irrigation water may be sufficient to cleanse the root-zone materials. Undetected urine damage will reveal itself later as a small, dead area surrounded by a lush green and succulent growth ring caused by the excess nitrogen. This condition will eventually restore itself, but when immediate correction is imperative, use the cup-cutter or sod-patching methods.
Critters underfoot Burrowing animals (typically moles or gophers) cause another kind of damage. They remove soil from the root zone. The removal of root-zone material may not always visibly affect the playing surface. In other cases, you'll find obvious mounds of dirt on the green. You can easily repair some of this damage, but some cases can be difficult. Moles usually cause more problems than gophers. A mole tends to burrow along just under the grass surface, disrupting a long line. A gopher typically constructs a nearly vertical waste tunnel through which it brings up excavated soil and piles it on the surface. The excavated soil often contains small pebbles that come from the main horizontal runs in which the animals live. These runs may be from 2 to 3 feet below the surface--where they don't directly affect the green.
You must carefully remove gopher mounds using a broad-bladed scoop shovel. Sometimes the gopher will bring up coarse sand and gravel from the drainage base of USGA-type greens. Remove this coarse material at once because it can damage greens mowers. Likewise, you must remove soil that has been contaminated with gopher dung. After you repair the damage, work any traces of soil into the green and pick up all coarse material.
Finding and repairing tunnels Use a coring tool to locate the direction taken by the gopher tunnel. Then use the two-cup-cutter technique to remove a core of green that contains the upper part of the gopher tunnel. Center the cup cutter on the gopher hole. Do not try to follow the tunnel. All cores should be vertical. If the tunnel has not remained entirely within the first core, it may be necessary to take a second core alongside the first, to capture the lower portion of the tunnel.
Install poison bait in the tunnel below the bottom of the core and cover it with a page of crumpled newspaper. Then, pour topdressing sand into the tunnel, filling it to the bottom level of the removed core. Tap the sand lightly with a wooden tool handle.
Finally, insert the replacement core taken from the green's edge as you would any other repair using the cup cutter.
When the burrow is entirely beneath the surface, but shallow, it will probably reveal itself by a softening and depression of the turf. Use the coring tool to find the extent of the damage. A quick way to expose the site is to make a deck hatch cut in the shape of the letter "I." You can fold back the two flaps created by the cut to expose the subsurface conditions. Then fill all voids with topdressing sand to correct the problem. If appropriate, install poison, tap the filled area to produce compaction equivalent to the normal green, and fold the turf flaps back into place. Topdress the surface, then remove excess sand and water with a fine spray until thoroughly damp.
USGA-type putting greens contain proper underground drainage systems and 12 to 14 inches of selected root-zone soil materials comprised primarily of sand. They will usually respond to repair efforts more promptly than greens of so-called "push-up" construction in which no effort has been made to provide subsurface drainage or to control compaction. Frequently, the grass on these greens has simply been planted directly on existing local topsoil. Therefore, you'll get better response on the USGA-type greens because they flush out more easily and they hold a perched water table, which provides optimum growing conditions for fast root and stem recovery.
And so... In evaluating putting green damage, do not be concerned only with the appearance and condition of the turf surface. Consider the entire underlying green structure, including the subsurface-drainage system, the full depth of root-zone material and the living root system. The objective is to restore all components of the putting green as nearly as possible to their pre-injury condition and that of the unaffected portions of the green.
Every incident of putting-green damage is a case unto itself. You must carefully examine and determine both the nature and the extent of the damage. Only then can you devise a proper and cost-effective remedy.
Joseph Phelps teaches turfgrass management at the Professional Golfers Career College of California--Temecula and manages Rancho del Cielo Golf Course, near Temecula.
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