demonstrateGrowing Trends article - NYSTA Web Site

“Heavy Repetitive Fall Overseeding To Improve

Low-Input Sports Fields”

A Report To The New York State Turfgrass Association

Principle Investigator:David Chinery,Cornell Cooperative Extension o f Rensselaer County,61State St.,Troy,NY 12180

Cooperators: Dr.Frank Ross i,Corne ll Univers ity, Ithac a,NY

Dennis Weatherwax,The Averill Park School District,Averill Park,NY

Jim Conroy,The C ity O f Troy,Troy,NY

Introduction: Overseeding,or distributing seed over an existing turfgrass area to increasedensity, is a traditional practice followed by many turfgrass managers.Unfortunately, success inoverseeding is not easily accomplished. To improve the chances that a high rate of seedgermination and establishment will occur, it is often recommended that some sort of cultivationis done before seeding. Types of cultivation include removing cores of soil (core cultivation),spiking,and vertical mowing.An aggressive overseeding program for a sports field might be tooverseed four or five times per year,hoping each time for some limited success.Home lawnsand commercial properties,which are not usually overseeded,might be overseeded once or twiceper year in a“best case”scenario.With limitations on the use ofpesticides increasing,overseeding might seem to be a better option than ever.However, turfgrass managers oftenreport disappointing results with overseeding(1). This is especially true on low-input fields,orfields where fertilizer, irrigation,weed management,and other cultural activitie s are limited ornonexistent. The cultivation requirement attached to overseeding can be disruptive to the use ofthe turf area in question,as well as adding costs. Clearly,easier and more effective ways tooverseed turfgrass areas are ne eded.

In August o f 2003 a re search project examining heavy,repetitive overseeding wasconducted on a two sports fields in the Capital District. This study was designed to put intopractice the ideas of Dr.Frank Ro ssi,Extension Turfgrass Specialist at Cornell University(2).Dr.Rossi has demonstrated that dramatic increases in turfgrass density were possible when highrates o f perennial ryegrass (Lolium perenne)were overseeded weekly on a simulated sports field.Objective: To demonstrate the practice o f heavy, repetitive overseeding on two low-inputCapital District sports fields using three seeding rates.

Procedures:Anyone who has visited practice soccer and football fields at high schools and parkswould probably agree that many are examples of ugly,beat-up turf and weeds. Two fields wereused in this study. The practice football field at Averill Park High School had compacted clayloam soil,a low pH(5.9),and was composed of bare spots,crabgrass,knotweed,plantain,dandelion,perennial ryegrass and Kentucky bluegrass. The second field was a multi-purposesoccer/football field in an inner city park,Prospect Park, in Troy. The soil was a loam with pH

7.5. The predominate species here were purslane,Kentucky bluegrass,perennial ryegras s,andgoosegrass. See Table 1 for a description of the initial composition of each field.

Four treatments were made: no seed(check plots),and overseeding at rates of2,6 and10 pounds of seed per 1,000 square feet (M),with three replications made of each treatment ateach site.Overseeding started on August 14 and continued weekly(except for the week of 9/18)until October 16,for a total of 10 applications in 11 weeks. Seed was distributed evenly acrossthe plots using a Gandy drop spreader. There was no cultivation done on the sites (other thanthat done by the football/soccer players or other field users); the seed was simply spread on theplots.No irrigation was supplied,as rainfall was abundant. Traffic and wear on the Averill Parkfield was concentrated in the center,and as a consequence one set of plots received light traffic,one medium,and one heavy.All ofthe plots at the Prospect Park field seemed to received equaltra ffic.

Results:Results for Averill Park field are outlined in Table 2. Turfgrass density increased foralltreatments,even for the check plots that did not receive overseeding. Small amounts ofturfgrass already existed in these plots,and when competition from the weeds was removed afterthey died from frost and cooler temperatures, the density of the grasses increased. This samephenomenon is also partly responsible for the increase in density of the overseeded plots as well,except for the three treatments that started with no turfgrass, in which case the increase in densitycan be attributed to overseeding alone. “Net increase in turfgrass density”was calculated as thedensity estimated at Week 11 minus the initial density. It is an attempt to measure the densityincrease caused by overseeding and to remove the influence ofa plot having some turfgrass atthe beginning ofthe study. The largest net increase in turfgrass density was seen in the 6 lbs./Mlight traffic plot,where density increased from 0%turfgrass at Week 0 to 100%at Week 11.The largest increase in net density for heavy traffic plots was also seen in the 6lbs./M plots,where density increased from 0 to 78.1%. Plots overseeded with 10 lbs./M had higher netincreases in density at Week 5,but the 6 lbs./M plots had greater net increase in density by Week11 of the study. For a visualcomparison, see Photo 1.

Table 2:Average percent turfgrass for eight treatments over ten seedings at Averill Park HighSchool

Photo 1 : From left to right: 2 lb./M,6 lb./M and 10 lb./M seeding rates in a heavily traffickedportion of the practice field at Averill Park High School

Very different results were obtained at Propect Park(Table 3). In the first few weeks ofthe study,perennial ryegrass seedlings were observed to be germinating in many ofthe plots.After Week 5,all of the plots, except the untreated checks,had a net increase in turfgrass density.The largest increase of50.9%was seen in the 10 lbs./M plots.After the week 5 observations,however, the 2 lbs./M plots continued to show an increase in turfgrass density,while the 6 lbs./Mand 10 lbs./M showed decreases. This was largely due to factors on the site. The middle of thisfield is very compacted and slightly depressed.Given the large amount ofrainfall during thetime period this study was conducted, this depressed area flooded repeatedly. Seed from treatedplots was observed to have washed away and moved onto untreated strips between the plots.Seedlings may have also been uprooted or died from flooding.While a net increase in turfgrassdensity was still achieved for all seeded treatments, these confounding factors decreased thepossible gains which could have been made. These results clearly indicate that the topography ofthe field will influence the success ofoverseeding.

Photo 2: The sports field at Prospect Park,with the worn,depressed area evident in the middleof the field

Conclusions: These results indicate that heavy,repetitive overseeding using perennial ryegrasscan improve turfgrass density on low-input sports fields.Greater increases were seen in plotsreceiving light traffic versus heavy traffic,yet even in plots with heavy traffic, significantincreases were still seen. The least successful situation seen in this study was on the ProspectPark field,where the uneven topography combined with heavy rainfall caused seed to wash out

of treated plots and seedlings to die.An even(or at least not severely rutted)field surface istherefore important to overseeding success.Overseeding at the 6 lbs./M rate gave the greatestincrease in net density and is also a less expensive alternative to the 10 lbs./M rate.

Is heavy,repetitive overseeding a cost-feasible proposition for sports fields?An internetsearch shows that perennial ryegrass seed prices range from$1.40 per pound to$2.80 per pound;wholesale prices and bulk quantities canpushthe low end price to less than$1.00 per pound.Given a$1.00 to$2.80 price range, the cost for a 10 week overseeding program at a 6 lb./M ratewould be$60.00 to$168.00 for one thousand square feet. If a school wanted to overseed themiddle of a worn football field(approximately 18,000 square feet), the cost would be in therange of$1,080.00 to$3,024.00.While this may not be an insignificant cost to financially-troubled school districts, it seems far less expensive than most pesticide treatments,or a lawsuitbrought about from a student athlete’s injuries suffered due to a poorly-maintained sports field.Since cultivation is not necessary with heavy,repetitive overseeding, further expenses areavoided,and fields can remain in play as the overseeding is taking place. The effect ofprovidinghigh-phosphorous fertilizer with overseeding should be studied, since such starter-fertilizer canincrease seeding success and is fairly affordable.

A project examining how this system performs in spring conditions on home lawns isplanned for 2004. If you have any questions or experiences with overseeding to share,pleaseemail me at dhc3@cornell.edu or call (518)272-4210.

Resources cited:

1. “High School Sports Fields: The Last Frontier Of Turfgrass Management,”Ed Leonardand David Chinery,New York State Turfgrass Association,2003.

2. “Aggressive Sports TurfOverseeding,”Dr.Frank Rossi, in“Cornell Field Day’03

Program Booklet,”Corne ll Univers ity,2003

Thanks to The New York State Turfgrass Associationforprovidingfundingfor this study, to Dr.Frank Rossi of Cornell Universityfor technical support,and to Dennis Weatherwax of theAverill Park School District andJim Conroyfrom the City of Troyfor research sites.