THE BIRTH OF APUTTING GREENA turf manager's guide for establishing a new putting green.BY CHARLES B. (BUD) WHITE

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e green complex sod is laid. Pre-plants areapplied. The putting surfaces are floatedout, ready for planting. The club has

invested hundreds of thousands of dollars in thisproject and you have the responsibility of gettingthe green complexes ready for play.The contractoris finished and now they're yours and you havelittle or no grow-in experience. Are you ready asthe turf manager?

Growing in new greens is probably the mostunderestimated challenge in golf turf manage-ment. This is because superintendents rarely havethe opportunity to establish a new green and,consequently, are not well versed on the subject.To bridge this gap, the key areas of a successfulgrow-in are presented in this article as a reference.When appropriate, this article also can serve as aneducational tool to help golfers, course owners,and real estate developers appreciate the scope ofwork involved in establishing new greens.

A poor grow-in can have devastating conse-quences to both the short- and long-term successof a project for several reasons. The more familiaraspects of growing in new greens involve soilfertility and disease suppression; however, thereare many other facets that are equally importantand are often overlooked or misunderstood. Thesemight include how to compact the rootzone,

when and how to reduce daily irrigation, whento mow the turf for the first time, and how tomanage the grow-in layer as the new turfmatures. To provide helpful instruction on thesubject of grow-in, this article discusses theprocess in chronological order, from seedbedpreparation to green opening.

SEEDBED PREPARATIONThe first phase of a successful grow-in is seedbedpreparation, which begins well before the first seedor sprig is planted. Preparing a seedbed basicallyinvolves firming up the rootzone to minimizedevelopment of depressions and tracking after turfestablishment, and applying starter materials topromote healthy seedling development.

The most effective method for settling therootzone after it has been pushed into the greencavity, shaped, and firmed is to bring the rootzoneto field capacity with extended irrigation on twooccasions before planting. To reach field capacity(i.e., water flows continuously out of the drain-pipe), a new green typically requires one hour ormore of irrigation from all of the sprinkler headssurrounding the putting surface. The secondheavy irrigation cycle is best scheduled the daybefore planting to insure that the seedlings orsprigs have adequate soil moisture.

The decision as towhen the first mowingshould occur is basedon vertical growth. notturfgrass density. Thisbentgrass (left) is readyfor the first cut 17 daysafter seeding. The Tif-dwarf bermudagrassgreen (right) is ready tobe mowed 18 days aftersprigging.

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The two- to three-foot-wide area at theedge of the greencavity is the mostdifficult to firm priorto planting. Extraattention should bepaid to this criticalarea during thecompaction step.

In addition to heavy irrigation, the rootzoneshould be compacted with a heavy roller. This,of course, is in addition to thorough floating(shaping) of the green, usually done with amechanical rake and drag mat. And, in cases wherethe sand is inherently resistant to compaction, therootzone should be rolled several times. In mostcircumstances, a l-ton roller will produce greatresults despite the natural hesitation of the super-intendent or project manager to operate such alarge machine on new greens. Keep in mind thatsoft greens can also benefit from rolling cifter turfestablishment.

An easy way to judge the proper firmness of anew green prior to establishment is to measurethe depth of footprints in the soil. Ideally, foot-prints should be less than 0.25 of an inch deep. Ifthey are deeper than 0.25 of an inch, additionalirrigation and rolling are needed. When testingthe firmness of a new green, give special attentionto the perimeter of the cavity, where settling afterestablishment is most common. This zone ofabout 24 inches at the green cavity edge is usuallythe most difficult establishment area of the greento compact. Multiple passes in this zone with amechanical rake, after irrigation, can be effectiveas the tires target compaction in this narrowband.

Once the rootzone has been compacted,pre-plant fertilizers are applied to create perfectagronomic conditions for seedling or sprig

development. Pre-plant materials, includingmicronutrients and chemical soil amendments, areassembled based on soil tests. Starter fertilizersshould not exceed 2 lbs. phosphorus per 1,000 sq.ft. as more will be unusable. If soil tests call formore phosphorus, apply the balance 30 days afterinitial pre-plant. A lIb. N per 1,000 sq. ft. appli-cation of slow-release nitrogen completes thepre-plant package. This provides a nitrogen sourcefor the first 10 to 12 days after planting so thatfertilizer does not have to be applied during thistender phase of germination/turf development.Readily available nitrogen is on hand in the soilsolution as soon as the turf has developed enoughfor uptake.

EROSION PROTECTIONErosion and sediment control are normally notconsidered part of green establishment, but theyare essential elements. Damaging erosion canoccur on a high-sand rootzone, even when theentire complex is sodded. Erosion damage isespecially likely at the putting green/collar transi-tion or sod line during establishment. Silt fencingslows and distributes runoff to prevent washing ofthe mix.

ESTABLISHMENTOnce the ground has been prepared, the secondphase of a successful grow-in is to establish theturf. Bentgrass seeding is best done in two direc-tions with a drop seeder. It is often mixed 50:50with a granular material such as a greens gradeorganic fertilizer to increase volume for easierdistribution. Rates for seeding creeping bentgrassshould not exceed 0.75 lb. of pure live seed (PLS)per 1,000 sq. ft. in each of the two directions.Sprigging rates for the ultradwarfs should be 25bushels (Georgia bushel measure) per 1,000 sq. ft.minimum or 8-12 live sprigs per sq. ft.

Mter seeding, tracking with the knobby-tiremechanical rake is the most common process.Extra tracking at the green cavity/collar transi-tion, before and after seeding, with good soilmoisture, usually provides adequate firmness.Again, careful attention to compaction at thegreen well edge will save much work later tryingto smooth this transition from collar to puttingsurface.

Tracking-in seed is efficient, but another optionis to lightly rake with the back of a leaf rake, help-ing ensure good seed/soil contact. This is donewith no down pressure to prevent planting the

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seed too deep. Light rolling completes the finish-ing task of seeding. This firms the surface, maxi-mizes seed/soil contact and removes the "fluff"at the surface, which reduces the tendency fordrying out in the upper 0.25 of an inch. Rollingoften is not utilized enough when seeding.

With the seed or sprigs planted in the ground,the next key element of establishment is watermanagement. During the first eight to ten days,the emerging turf will require frequent irrigationto prevent desiccation. The key to water manage-ment during grow-in is stepping down waterfrequency and amounts properly after initialrooting or germination to enhance maturity. Thequestion of when to start this water reduction is acommon query of inexperienced grow-inmanagers. It is usually not the timing of waterreduction that creates problems, but instead it isthe manner in which water reduction is initiated.

It is vitally important that in the initial stagesof water reduction, the run times of irrigationcycles be reduced first and not the start times. Forexample, a program is set up for new bentgrassgreen establishment in which five to six starttimes a day are programmed, and generally about20 to 22 minutes per green (3-4 minutes per head)is the desired run time. The initial thought mightbe to first reduce the number of start times aftersignificant establishment to assist with root devel-opment. However, this can create drought stresson the bentgrass, especially on a late spring seed-ing. The same is true with bermudagrass sprig-ging, particularly in August. Remember that thegrass is quite immature and there is not enoughroot system eXploitation of the soil volume toallow for adequate moisture recovery. This isespecially true in a new high-sand or straight-sand green profile, which initially is more suscep-tible to drying out at the surface. Significantdrought stress can occur within the plant beforevisual signs are apparent with this type of waterreduction versus proper initial reduction.

The proper reduction sequence is to firstreduce the run times of each cycle to achieve areduction in the amount of water being applied.It is much more efficient to reduce run times -the amount of each application - with thenumber of applications remaining the same. Thisreduces the chances of drought stress because thetender seedlings or new sprigs do not go too longbetween irrigation cycles, and the upper half inchof soil moisture is more adequately maintained.Mter some hardening of the plants, start times can

be reduced to achieve further maturity androoting.

Remember also that start times are notnecessarily evenly spaced over the 24-hour clock.The start times, especially on bentgrass springseeding, must be concentrated during the latemorning and early and late afternoon periodsbecause of the greater tendency for drought stressduring the heat of the day. Commonly, the firstwatering occurs about 7:00 AM - 8:00 AM, andconcentrated water begins about 10:30 AM -11:00 AM. The last cycle is set for about 6:00PM - 7 :00 PM, with no water applied during thenight. Night irrigation is not needed and canpromote disease activity.

SPRAYINGInitial pest- and disease-controlproducts and nutrient applicationsshould be made with a walkingboom. Freqently, new greens are toosoft for a self-contained sprayer forthe first six to eight weeks afterseeding. If the superintendent is notprepared with a walk-type boom, hemay be forced to rut the greens toapply a control product in the eventof a disease outbreak. This specializedpiece of equipment should not beoverlooked for this phase of greendevelopment.

A fungicide application afterplanting is usually made to preventdamping-off. This can be a very activeand devastating pythium diseaseproblem if environmental conditionsare favorable. The fungicide can beapplied in spray or granular form atthis stage. Also, treated seed ispreferred, if available.

MATURATIONThe third and final phase of a successful grow-ininvolves nurturing newly established seedlings orsprigs into a mature turf canopy that will holdtogether under the rigors of daily play. The key tothis endeavor is the light application of fertilizer ona frequent schedule. It is commonly thought thatfertilizer is applied during grow-in on a seven-dayfrequency, with about 1 Ib. nitrogen or potassiumper 1,000 sq. ft. per application as the standardrate. Grow-in is accomplished at a much moresuccessful and rapid rate when this frequency is, in

Improperly firmingthe rootzone mix priorto planting results insevere scalping ofthe turfgrass.

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the initial phases, reduced from a seven-day appli-cation rotation to a five-day rotation at lighterrates, usually 0.3-0.61b. N per 1,000 sq. ft. Ratesdepend on turf species and weather.

Potassium nitrate (KN03) has been utilized forbentgrass grow-in with excellent success usingthe above outline. Ammonium sulfate (NH4S04)

should be a primary nitrogen source for bermuda-grass, along with adequate iron, magnesium, andmanganese. This is rotated every third applicationas a complete material. Mter four to five weeks,the strategy changes by reducing the frequency.Micronutrient sprays and/or chemical soil amend-ments are applied as needed to assist in turfmaturity. A complete analysis, granular, slow-release material should be the foundation toaddress soil and plant nutrient needs during thishigh-input phase of development. This alsocombats the tendency for nutrient depletion fromthe higher irrigation cycles still being utilized.Remember, watering in fertilizer materials isvitally important, and applications during the heatof the day are to be avoided.

Grow-in fertility rates are considerably higherthan maintenance rates for obvious reasons.Generally, on a USGA spec green the nitrogenrate the first year after seeding will be approxi-mately 8-11Ibs. ofN per 1,000 sq. ft., dependingon region, rainfall, physical properties of thegreens mix, and water management. Research hasshown relatively little leaching loss of fertilizerswhen good water management is utilized.Straight-sand construction requires more fertilitybecause of reduced water retention and nitrogenholding capacity.

Grow-in managers often struggle with applyingthis high rate of fertilizer on establishing bentgrassgreens when they have been utilizing maintenancelevels ofl-3Ibs. N per 1,000 sq. ft. for so long.Young seedlings can develop stress from inade-quate nutrition very quickly in new sand root-zone environments, and proper levels must bemaintained. The same, of course, is true withbermudagrass sprigs. Nitrogen levels will approxi-mate 9-12Ibs. ofN per 1,000 sq. ft. for the frrstyear on Tifdwarf or ultradwarf greens.

A 1:1 ratio of nitrogen:potassium has been theusual approach in the first year of fertility manage-ment. Routine phosphorus and minor elementsare applied according to soil and tissue tests.Follow-up soil tests are very helpful at about 4months and 10 months after planting. Tissueanalyses during grow-in can help monitor

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nutrient availability. Nitrogen levels during grow-in should be 5.25-6.5% in bentgrass and 6-7% inbermudagrass as benchmarks for monitoring.These levels are higher than is ideal for mainte-nance.A slow-release, granular fertilizer with acomplete analysis should also be included in thefertilizer schedule during turf maturation to offSetthe rapid leaching of nutrients caused by frequentirrigation. When applying granular fertilizers,make certain to avoid the heat of the day andirrigate immediately afterwards to prevent burn.

With the turf properly fed and watered, itusually does not take long for it to require mow-ing on a regular basis. The act of mowing shouldnever be underappreciated during the grow-in ofnew greens, as it can have a direct impact on turfquality. The most common mistake with respectto mowing is waiting too long to mow the turffor the first time and doing so at too high acutting height.

The determining factor for when to mow anew green for the first time should be the heightof the turf, not its density. However, it is easy forthe turf manager to look at a green and believe itis not quite ready. Grow-in managers often allowdensity to be too great a part of the equation ofdetermining when mowing is needed. Densityhas nothing to do with mowing new greens - itis strictly vertical growth development. Rememberthis in evaluating when mowing shouldcommence.

As a guideline, mowing should begin when theheight of the turf just surpasses the upper limit ofits preferred cutting height range. For example,many of today's creeping bentgrass and hybridbermudagrass varieties have a cutting heightrange between 0.120 and 0.180 of an inch. Usingthe upper limit of 0.180 of an inch as the heightadjustment for the mower, the first mowingshould commence when the turf reaches a heightof approximately 0.200 of an inch.Within fourto six weeks after the first mowing, the cuttingheight should be whittled down to the midpointof the turf's cutting height range or, in ourexample, 0.150 of an inch.

This guideline may not be appropriate if therootzone is prone to rutting after mowing begins.In this instance, the turf has to be protected fromscalping while it is trying to mature. Nonetheless,the objective for any grow-in should be to workthe cutting height down to the middle of theturf's cutting height range as quickly as possibleto promote lateral growth and stand maturity. The

mowing rule of thumb has been tonever remove more than ~ of the leafat any mowing. During establishmentthis target is better set at X to reducethe chance of scalping or shock.

Late morning or afternoon mowingis also important in the early stages.A dry turf will mow cleaner and haveless likelihood of pulling seedlings outof the ground. Frequent mower back-lapping will be required. Solid frontrollers should be used on the puttinggreen mowers for the first months, asthe grooved rollers are too damaging.They can also dig into the somewhatexposed rootzone surface. The firsttwo to three cuts are done withoutbaskets to reduce weight; after that,baskets are used.

Scouting during the early stages of developmentis a critical part of grow-in management, to keepa close eye on disease development and insectactivity. When establishing new greens, scouting isactually so important that it should be a dailyroutine. If left unchecked, there are numerouspathogens that can literally destroy a stand ofyoung plants in a matter of hours.

Daily scouting is also essential for monitoringweed contamination. Rouging is a term used bysuperintendents in the South and refers to check-ing greens for weeds on a daily basis. The mostcommon weeds found in southern greens arenuts edge and off-type bermudagrasses. Creepingbentgrass greens can also become contaminatedwith invading bermudagrass from the surroundingarea or by Poa annua blown in on the wind.

Topdressing completes the management circlewhen it comes to producing a smooth, successfulgrow-in. Throughout the grow-in of a newgreen, topdressing should be applied at a light rateof 0.5-0.7 cu. ft. per 1,000 sq. ft.Working the sandinto the young turf without bruising, however, isoften a bigger issue than rate and frequency ofapplication. Herein is the great value of a spin-type top dresser capable of applying sand evenlyenough to work down into the turf with irriga-tion alone. As maturity progresses, the turf willbecome more wear resistant, but not so much thatone should consider using a steel dragmat towork topdressing into the turf canopy.

The first topdressing application for creepingbentgrass greens can normally be scheduled fourto six weeks after seeding. Hybrid bermudagrass

greens are usually ready for the first topdressingapplication three to four weeks after sprigging.Light topdressing applications on sodded collarsand approaches should be scheduled within fiveto six weeks for cool-season grasses and two tothree weeks for warm-season grasses.

AERIFICATIONOne of the goals of early turf development is tomaximize the growth rate by using relatively largeamounts of water and fertilizer. Under theseconditions, the turf unavoidably produces thatchat an accelerated rate. Moreover, due to earlytopdressing restraints, the thatch layer is lessporous and denser in composition, producing alayer more subject to hydrophobic or anaerobicconditions. This unique thatch condition givesrise to the term grow-in layer.

The grow-in layer begins developing on newgreens in a matter of a few weeks and is oftenunderestimated in terms of its long-term impacton turf performance. The high accumulation oforganic matter just beneath the turf surface is notreadily evident to the eye, but rather to the touch.The detrimental effects of a grow-in layer usuallybecome apparent after a green has been openedto daily play, as would a similar layer created bysodding a new green. The principal detriment isthe sealing off of the soil surface that, in turn,causes water to stagnate in the grow-in layer. Thisis why scheduling aerification a few months afterthe establishment of a new green is often criticalto its long-term success.

Desiccation onmounds or greenslopes occurs veryquickly when the timebetween the irrigationcycles is lengthenedtoo quickly afterplanting.

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This early aerification may seem radical, butcompaction relief is not the reason for aerificationat this point. The goal is to permanently break upthe surface tension created by this newly developedgrow-in layer of thatch. It is not only critical toaerify new greens at this early stage, but hollowtines must be used to physically remove a corefrom the green. Solid tines are not beneficial inthis case.

On the whole, the first two aerification treat-ments of seeded creeping bentgrass greens aredone with %-inch-diameter hollow tines on 2-inch centers. Afterwards, greens develop greaterfirmness and surface stability and can be aerifiedwith larger tines on i-inch centers. The samegeneral principle also would be true for hybridbermudagrass greens.

TOUCH-UPAs is often the case, some things tend to go astraydespite the best-laid plans. During the grow-in ofnew greens, there are always spots on the puttingsurface with poor or no turf coverage that willrequire touching up. This occurs for many reasons,such as vandalism, animal damage, erosion duringa severe storm, ete. The most common area is thecollar! putting surface transition edges because ofthe instability reasons described above. If firmnesswas not achieved prior to the first mowing, severescalping will occur. A grooming reel from a putt-ing green mower attached to a handle makes a

great tool for roughing up bare areas that need tobe reseeded or resprigged.

OPENING THE GREENSBefore the grow-in is complete, it will probablybe necessary to withstand golfer pressure to openup the green(s) ahead of schedule. Understandably,the pressure arises when the putting surface(s)appear mature to golfers. Remaining patient foran additional four to six weeks, however, is criticalto give the new turf time to produce horizontalstems that bind the plants together and allowthem to survive concentrated foot traffic aroundthe hole locations.

Growing in a new putting green is a long andarduous process and requires a high level ofmanagement skill. Plenty can go wrong withoutcareful monitoring. With knowledgeable planningand quality control management, however, mostproblems can be avoided. The craftsmanship andthe enjoyment of the project will certainly be thebetter for it. Good luck!

Special thanks to Keith Ihms, CGCS; Kevin Nettles;Scott Bush; and Neal Dube for their assistance in gatheringphotographs for this article.

BUD WHITE is the agronomistfor the Mid-ContinentRegion and has worked with superintendents on morethan 200 construction/renovation projects.He is also theauthor if Turf Manager's Handbook for GolfCourse Construction, Renovation, and Grow-in.

The grooming reel isan excellent touch-uptool to use for spotseeding or breakingsurface algaeformation.

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