Sun, Ice, and Climatological Normals

Since my last post I've been to England and the UAE, Philippines, Vietnam, Thailand, and Japan. I've seen most grass types but not many diseases; a bit of fairy ring, some dollar spot, slime mold, and Curvularia. What I have seen is a lot of variability in the weather, and especially in Asia I have seen the typical cloud cover, rain, and associated low sunshine hours that are so widespread during these months of the year.

When we look at the factors that influence turfgrass growth, we can identify nutrient status, water status, temperature, and light as being the primary factors. But with drainage, supplemental irrigation, and fertilization, turfgrass managers are able to control the nutrient and water factors, at least in theory, which leaves just temperature and light as the factors influencing growth. I find it useful to look at the climatological normal data, as seen in the chart below for August, or in this interactive chart with data for the entire year, to evaluate how the temperature and sunlight may influence turfgrass growth at a particular location.

Zoysiagrass outperforms seashore paspalum and bermudagrass in low-light conditions, both in the research setting and in the field throughout Asia. In tropical Southeast Asia, where the temperature remains relatively constant throughout the year at an optimum level for warm-season turfgrass growth, it is the light factor that controls the growth of the grass. Zoysia is especially well-suited to that environment.

An environment that creeping bentgrass is not well-suited to is the summer in Japan; a place like Osaka (where bentgrass is almost universally used on putting greens) is hotter during August than cities such as Singapore, Honolulu, and New Orleans. I've been making some measurements of the changes that take place in surface temperature and soil temperature when ice or ice water are applied to creeping bentgrass greens in Japan. I've been surprised at the persistence in soil cooling from the melted ice, although clouds and rain have moved in this week and I've been unable to continue these experiments.