Green Side Up!Sodding putting greens can be a viable method of establishmentwith proper care, good product, and reasonable expectations.BY MATT NELSON

Given the option, most cool-season turfmanagers would prefer to establishputting green turfgrass directly from

seed. Seeding enables turf grass plants to germi-nate, establish, and mature in the rootzoneselected for the greens. Strong roots will developin a well-oxygenated sand rootzone, and thedeveloping thatch/mat layer can be integratedwith sand during grow-in to avoid layering andmaintain optimal soil structure. Surfaces can beprepared during construction and maintainedduring grow-in with topdressing, grooming,and rolling to provide superior smoothness andplayability. Typically, creeping bentgrass estab-lishment from seed requires at least 12-16 weeksof good growing weather for sufficient matura-tion to tolerate play. Seeding in late summer ispreferred, taking advantage of warm soils, cool-ing nights, reduced disease pressure, and limited

physiological stress for best establishment. Whengrow-in goes well, greens seeded in mid to lateAugust are ready for play by late Mayor earlyJune of the next year across most of the northernUnited States.

At many northerly and higher-elevation sites,however, a limited growing season extends theamount of time required to open seeded puttinggreens. A longer grow-in may not fit the time-line at higher-end projects dependent upon realestate sales and/or revenue generation. Sod hasbecome increasingly utilized at these types oflocations to compress the window between con-struction and opening.

Winterkill and renovation projects also con-tribute to the demand for high-quality puttinggreen sod. Replacing putting green turf domi-nated by annual bluegrass (Poa annua) withcreeping bentgrass sod significantly improves

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A long grow-in timedoes not always fitinto a projecttimeline. Sodprovides anopportunity forrapid putting greenestablishment.

turf grass reliability over the winter. Installingbentgrass sod will not overcome limitations withrespect to shade or poor design, but improvedresistance to freeze injury can be expected.

Regrassing with improved creeping bentgrasscultivars also may be a viable means of nleetinggolfer expectations with respect to puttingquality and turf grass performance.! Many of thenewer cultivars of creeping bentgrass exhibitgood tolerance of close mowing, disease resist-ance, outstanding morphological characteristics,and enhanced overall stress tolerance. In someclimates it is a real challenge to meet currentgolfer expectations for ball roll and consistencywith a mix of annual bluegrass and older geno-types of creeping bentgrass due to anthracnose,nematodes, and/or physiological stress.

Sod quality and production has evolvedconsiderably in recent years, meeting industrydemands for agronomic excellence and superiorplayability in a short time. This article willaddress some of the major issues regarding putt-ing green sod selection and establishment for thebest opportunity for success. Although the infor-mation in this article pertains directly to creep-ing bentgrass putting green turf, the principles ofagronomy should be pertinent to the culture ofbermudagrass sod in warm-season climates.

SELECTING THE BEST SODOf paramount importance when selectingputting green sod is rootzone compatibility.Sod grown in soil that is finer textured than

the underlying rootzone will likely pose estab-lishment difficulty, as excess moisture held inthe sod layer will limit root growth and gasexchange. Creeping bentgrass sod grown in aclay, silt, or loam soil placed on a sand rootzoneis practically doomed from the start and shouldnever be considered. Superintendents or projectmanagers should visit potential sod farms and askfor particle size distribution analyses from thetop one or two inches (depending upon cuttingdepth) of the sod rootzone. These tests resultscan be compared with rootzone mix parametersof the putting greens to estimate physical com-patibility. If in doubt, seek input from an agrono-mist, university extension specialist, or a USGA-accredited physical soil testing laboratory.

In recent years, soilless sod has become avail-able in the western United States. This patentedtechnology involves producing creeping bent-grass sod on thin plastic with only enough sandto germinate seed and establish the turf The riskof rootzone incompatibility nlaY be reducedwith this type of sod, although organic matteraccumulation must be managed appropriately, aconcern with practically all types of bent grasssod. Sod grown on plastic does not requirebottom cutting for harvest; thus, turf grass rootsremain intact although bound in the thatch/matlayer. Producers market the lack of root cuttingas a benefit to establishment. Sod produced onplastic can usually be harvested at variouswidths, since undercutting is not required.

Selecting young sod (less than one year or so)is usually desirable, since thatch will be moremanageable. Excess thatch can restrict gasexchange into the rootzone, hold too muchmoisture near the surface, decrease tolerance ofenvironmental extremes, increase the likelihoodof mechanical injury as cutting heights arelowered, and compromise recuperative potentialof the turf About 0.75 inch of thatch or lesswould be considered desirable when selectingputting green sod.

Cultivar selection can be based upon regionalNTEP (National Turfgrass Evaluation Program)trials, regional performance, compatibility withexisting turf (if only sodding one or a fewgreens), player expectations, and maintenancecapability. If a major renovation involving sod isto be carried out, most producers will contractto grow the cultivar of choice and, withinreason, manage accordingly. Perhaps growthregulator applications and/or topdressing will be

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desired, and these practices arefeasible provided equipmentand costs are identified. Long-distance transport for the sodmay require refrigeration toavoid desiccation and damageto the sod.

ESTABLISHMENT TIPS -GREEN SIDE UP!Anybody who has had thegood fortune to have hands-on involvement with majorsod projects has heard all theinstallment jokes, none ofwhich will be repeated here.Jokes and puns aside, however,there are some tried and truetips worth considering whenworking with putting greensod.

Using big rolls of sod isnot necessary for a successfulproject, but they provide some advantages. Bigrolls speed the installation process, which can beadvantageous under many circumstances. Fewerpieces of sod also mean fewer seams forpotentially smoother surfaces earlier, slightlyeasier management, and reduced risk of edgedesiccation.

The prepared finished grade should be smoothand firm. Ideally, the surface should be firmenough that footprints are less than 0.25 inchdeep. Check grades with a digital level andsurvey equipment to ensure that putting greenshave positive surface drainage for water dis-charge. This point is especially critical wherewinterkill is an issue; water from melting snowand ice needs to flow off of putting green turf

When renovating existing greens, cut theexisting sod deep enough to remove organicmatter from the upper soil profile. Leavingbehind excess organic matter compromises soilstructure and potentially skews the balancebetween capillary and non-capillary porosity.Roots from the new turf grass sod will have adifficult time penetrating thatch or mat layerspresent in the rootzone. Aggressively cultivatingthe rootzone of older greens prior to installingsod presents a good opportunity to modify soilswith sand for improved physical properties andperformance. Conventional or deep-tine aerationboth are viable options, depending upon root-

zone properties, and aggressive cultivation priorto sod establishment can enhance success withpotentially reduced surface disruption duringestablishment. Physical testing of existing root-zone parameters prior to renovation and regrass-ing will provide valuable insight into necessaryrootzone modifications.

Install sod as uniformly as possible and, withrenovations, pay special attention to grade tie-ins. Offset seams for reduced displacement,mechanical damage, and desiccation. Avoiddamaging the prepared finished grade or impart-ing excess wear on newly installed sod by usingplywood to walk on or drive installationmachinery.

Once sod is installed, aggressive rolling willfirm and smooth the surface. Walk-behindvibratory asphalt rollers or riding one-ton asphaltrollers typically provide best results. Rolling canbegin immediately after the sod has been laidand can be repeated every few days during theestablishment process. Smoothing the surfacelimits mechanical damage (scalping) frommowers as height of cut is reduced in preparationfor play, and it also helps provide optimal playingquality.

Begin mowing at a reasonable height of cut assoon as possible to avoid scalping and mechanicaldamage. It is important to begin mowing soonafter installation to avoid letting the turf become

Sod grown on plasticmay reduce soilcompatibility issuesand does not requirecutting turfgrassroots during harvest.

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Using plywood helpsto limit wear injuryto sod and is a goodtip during successfulinstallation.

puffy and to start the process oflowering theheight of cut in preparation for the plannedopening date. Floating-head, walk-behindmowers equipped with a smooth, out-frontroller mininlize the potential for mechanicaldamage. Be diligent with cutting height reduc-tions to prepare the surface for play, but don'thesitate to raise the height of cut in the event ofexcessive scalping, as nlechanical damage cantake a long time to recover and may jeopardizethe opening date, playing quality, and short- andlong-term performance of the turf

Taking the time to hand top dress the sodseams will limit the potential for mechanicalinjury, lessen the potential for desiccation of sodedges, and hasten the development of the desiredsurface smoothness. Green colored sand hasworked well for seam topdressing during coolspring weather, as colored sand will absorb moreheat and some superintendents report quickerstitching of individual sod pieces. Heavy sandtopdressing of the entire sodded green at rates of250-350 lbs. of sand per 1,000 sq. ft. for the firstthree to four weeks also will be very importantfor surface smoothing and preparing the greenfor play. Integrating sand into the organic matterlayer as quickly as possible also will establish sandas the dominant component of the thatch/matmatrix and provide balanced soil structure forgood agrononlic performance and playability.Physically incorporate sand into the turf grasscanopy by brushing or dragging.

Aerating new sod as quickly as possible hasrepeatedly demonstrated great results in the field

with respect to vigorous establishment. Aerationcan often be conducted within the first week ofinstallation with the proper technique. Small-diameter solid or hollow tines (0.25-0.375 inch)provide good results since the primary objectiveof early cultivation is to maintain good gasexchange through the sod layer and encourageroots to penetrate into the underlying rootzone.Repeating this procedure once or twice prior toopening the greens is advised since cultivation istypically more difficult to employ once thegreens are opened for play. Periodic aerationwith small-diameter solid tines or slicing unitsduring the first season will safeguard turf healthby promoting gas exchange into the rootzoneand preventing sealing that is often a concern onnewly sodded greens. Watch for signs of reducedturf vigor, poor recuperative potential, ordevelopment of black algae on the surface. Theseconditions usually indicate insufficient oxygenin the rootzone.

Fertility recommendations vary considerablybetween new construction and renovation ofexisting greens. Soil testing is a good place tostart. With new construction, pre-plant fertilityusually includes a homogenous starter fertilizerapplication at a rate of around 1 lb. nitrogen andPzOs per 1,000 sq. ft. Good results have beenobserved where starter fertilizer is augmentedwith additional controlled-release fertilizer in abalanced formulation of nitrogen, phosphorus,and potassium at 1-2Ibs. each per 1,000 sq. ft.

Pre-plant fertilization rates for existing root-zones will be lower than new construction.Consult with your regional USGA agronomist,soil testing laboratories, and/or university turf-grass extension personnel for best advice at yourparticular location.

Once installed, relatively modest and frequentapplications of complete fertilizer usually providegood results.

IN-HOUSE CUSTOM SODOccasionally there is a need to renovate one ormore greens at an older golf course not experi-encing agronomic problems. The design may beoutdated, with excessive slopes for modern greenspeed or insufficient area to adequately supportthe volume of play. Z Property sales or trades maynecessitate relocating a green. In these instances,matching the turf grass composition and play-ability with the existing greens is a primaryobjective. At most cool-season golf courses, this

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constitutes a mix of various genotypes of annualbluegrass and creeping bentgrass.

With proper planning, a nursery green can becreated utilizing aeration plugs from the existinggreens and perhaps a little bentgrass seed.3 Usablesod normally can be obtained in about a year,depending on the growing season, managementcapability, and nursery location. Similar manage-ment protocol will apply as suggested above,and using the best available means to harvestuniform sod will yield the best results.4

DETERMINING AN OPENING DATECreeping bentgrass putting green sod usuallyrequires at least 4-6 weeks of decent growingweather for adequate establishment to tolerateplay. Root growth should be at least a few inchesinto the rootzone for anchoring and stability,and to take up sufficient nutrients and water forvigorous growth and recovery. Surface prepara-tion needs to be advanced enough to providegood ball roll characteristics and tolerate reason-able mowing without scalping.

Ultimately, reasonable expectations need tobe established early on in the construction andrenovation process. Opening newly soddedgreens too early can jeopardize performance,result in turf grass failure, and threaten a signifi-cant investment. Green speed expectationsshould be properly balanced with long-termperformance during the first few months ofplaying the sodded greens. Scheduling sometime for cultivation and topdressing will safe-guard success. Closing one day or half a day perweek and providing the turf a chance to recoverfrom wear and stress can make an enormousdifference in putting green performance.

Among the best recommendations formanaging newly sodded greens is to give thegolf course superintendent and green committeesole discretion to close the greens should turf-grass decline or failure become evident. Newsod generally does not have the recuperativepotential of established turf, and a modest toheavy volume of play can result in rapid andsignificant decline. A "soft opening" during thefirst few weeks of play, whereby the greens areplayed for 3 or 4 days and then rested for 2 or 3days is often a good way to allow golfers on thegreens fairly quickly (4-6 weeks after installation)while still enabling the new sod to establish andmature. Every situation is slightly different, butadopting a fairly conservative approach with

respect to agronomic realities and golferexpectations is advised.

GREEN SIDE UP!Sod production methods have evolved consider-ably in the past decade or so and present viableoptions with respect to turfgrass establishmenton putting greens. Production on constructionspecification sand, washed sod, and sod grownon plastic have facilitated smoother and moresuccessful projects and can provide champion-ship-level putting surfaces in a previouslyunattainable time frame. Proper planning,product selection, installation, and constructiontechniques, and good management make soda realistic option for putting green turfgrassestablishment at new or existing golf courses.

LITERATURE CITED1. White, C. 2006. Rebuild or resurface. USGA GreenSection Record. 44(1):1-6.

2. Kinder, B., M. Condon, D. Weiss, R. Phelps, G. Bartold,J. Gamble, and M. Nelson. 2005. Renovation at RollingHills. USGA Green Section Record. 43(5):30-33.

3. Gross, P.J. 1999. Poa/Bent nurseries - a perfect match.USGA Green Section Record. 37(2):9-11.

4. Nelson, M. 1997. Sew it seams. USGA Green SectionRecord. 35(3):7.

AUTHORSNOTE: The author would like torecognize James Beebe, CGCS, Priddis GreensGolf and Country Club, for his contributions tothis article.

MATTHEW"SOD" NELSONis senior agronomist inthe USGA Green Section's Northwest Region,visiting golf coursesin the Rocky Mountains of theUnited States and Canada.

Greenside up!An instantputtinggreen.

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