The Ohio State University

Home SportsNotes Growing grass during late fall and early spring can be a challenge because not only does the weather become less favorable, but also the amount of light available to the turf declines noticeably. This is because at this time of the year, the apparent path of the sun in the sky is much farther south than it was during the summer. At noon in December, the sun is about 47 degrees lower in the sky than in the summer and the intensity of sunlight is similar to what we would expect at about 8:15 in the morning in June. The result of this decrease in sun angle is a significant decrease in light intensity (which is why you don't see UV warnings in the newspaper and can sit out in the sun all day long and not get sun burned at this time of year).

Turf growing in shaded conditions becomes elongated and has soft, lush growth. In addition, the turf canopy and playing surface take much longer to dry out after a rain event or after dew accumulation. When the playing surface stays wet for prolonged periods of time, the turf is more susceptible to disease and root growth is restricted. The turf eventually loses density and the area gets worn away much more quickly, resulting in poor playing surface performance and slippery playing conditions for the athlete.

There are several ways to improve turf performance in shade:

* Standard cultural practices include the following - Increasing mowing height, cautious use of fertilizer and irrigation, and frequent tine aeration.

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* Installation of Louvre windows and transparent roof panels (see picture left taken at Manchester City Stadium, in January) that allow some light and air movement into the stadium. This is especially critical in wrap-around stadiums where corners are closed.

* The use of large fans or blowers that can be pushed across the field/pitch and used to dry the surface out. Standing water can also be removed with squeegees

* Topdressing applications of porous ceramic/calcined clay products like Profile, that absorb moisture prior to a game and provide firm footing. During research at Ohio State Profile was shown to improve wear tolerance and traction, provide a firm playing surface and act as a topdressing for new seedings. The uniformity and size is similar to medium coarse sand but it is less abrasive. We found that applications of sand during the playing season can injure the turf leaf tissue and reduce turf density during traffic.

* Applications of Primo (trinexapac-ethyl) made during the season not only prevents leaf elongation but also improves turf density in shade. Research undertaken by Dr. Gardner and Ed Nangle suggests that turf decline under shade conditions can be delayed somewhat if the turf has been treated with a growth regulator.

* Portable light racks are becoming more popular in Europe, with several Premiership clubs using them during the winter to promote some kind of growth during the playing season.

Thanks to co-authors (text & pictures): Dr. Dave Gardner, Dr. Karl Danneberger, Lee Jackson & Filipa Mateus De Almeida

Posted by Pam Sherratt