Florida's 2005 spring will be remembered as one of the best ever for golfing weather. The Chamber of Commerce mild temperatures and low humidity that persisted until the very end of May was perfect for getting in a full eighteen holes or a quick nine in the late afternoon. While above average rainfall was recorded in May that minimized the typical onset of drought stress, rainfall events were not frequent enough to impact play. The vast majority of golf course superintendents throughout the state, however, have a totally different perspective on this "wonderful" spring weather because they once again have to deal with a case of the spring transition blues.

During the last weekend in April, record setting nighttime lows in the 30's in North Florida and mid to high 40's in South Florida brought bermudagrass growth to a complete halt. While temperatures did increase, daytime highs in the low-80's and nighttime lows in the 60's persisted. These temperatures were sufficient for bermudagrass green-up, but not for the resumption of sustained active growth. This was true regardless of fertilizer and other maintenance inputs. Furthermore, the mild temperatures and timely rainfall through May was ideal for growth of winter overseeding. In South Florida, the transition process out of interseeding/overseeding is typically completed by mid to late April. During TAS visits over the past couple of weeks about 40% to 60% perennial ryegrass coverage still persists in fairways. As you move further north in the state there is a progressive increase in the amount of persistent overseeding material. With the rapid onset of hot and humid summertime weather, a fairly rapid decline in the remaining overseeding material occurs, exposing areas of weak and thin bermudagrass coverage. Torrential rains during the first full week of June only further favored survival of the cool season grasses and limited bermudagrass growth and recovery. For a lot of golf courses the transition blues will continue for a while longer.

With persistence of overseeding material, additional competition and stress is exerted on the base bermuda. In the March/April 2005 Green Section Record, Dr. Fred Yelverton's article on spring transition contains the statement "in most climates, bermudagrass needs about 100 days of growth without ryegrass competition". While normally not a concern, especially in Central to South Florida we are quickly approaching the point where a full 100 days for redeveloping optimum bermudagrass health and quality will not be available. If you are reading this update and still have overseeding material persisting on your course, it would be a good idea to immediately review Dr. Yelverton's article and consider implementing herbicide treatments to accomplish a chemical transition to remove the overseeding material as quickly as possible. (http://www.usga.org/turf/green_section_record/2005/mar_apr/spring.html)

Source: John Foy, jfoy@usga.org or 772-546-2620