Overseeding season is approaching rapidly, and now is the time to discuss seeding rates, strategize how many acres to overseed, and whether to overseed ultradwarf bermudagrass putting surfaces. Very recently, an informal survey regarding overseed rates was initiated with the help of Superintendent Bill Kostes at DC Ranch, and Ed Shimkus, superintendent at The Golf Club of Scottsdale. The survey revealed some very interesting trends with regard to overseeding or not overseeding in the Phoenix area.
Fairways and Roughs
- 44 (18-hole equivalent) golf courses responded to the survey.
- 23 respondents reported that they are NOT overseeding roughs this year, a slim majority at 52%.
- Three courses will not overseed any turf areas this year.
- One property, consisting of six, 18-hole equivalents, will not overseed two of the courses each year, while the remaining four are overseeded wall-to-wall (all turf areas save the greens, which are bentgrass).
- The average seeding rate for fairways is 622 lbs/acre, with the lowest rate at 200 lbs/acre and the highest at 900 lbs/acre.
- The average overseeding rate for roughs, for those who continue to seed, is 550 lbs/acre, with the lowest rate at 300 lbs/acre and the highest at 850 lbs/acre.
- Perennial ryegrass remains the most popular seed choice, although some courses that have Rapid Blight concerns include fine fescues in their mix, typically at a ratio of 80:20 with perennial rye:fine fescue.
- Of the 44 responding courses, the breakdown for greens is as follows:
- 11 of the 18-hole equivalents have bentgrass greens (25%).
- 22 courses have ultradwarf bermudagrass greens (50%).
- Of these with ultradwarf greens, 6 courses will NOT overseed (27%).
- For those who continue to overseed, Poa trivialis is the most frequently used seed type at an average rate of 10 lbs/1000 sq. ft.
- Courses with Rapid Blight concerns generally mix Poa trivialis with bentgrass and/or fine fescues. One course uses the following mix: 4 lbs Poa trivialis + 4 lbs of velvet bentgrass + 10 lbs of fine fescue per 1000 sq. ft. Another combination that several courses use is an 80:20 mix of Poa trivialis and creeping bentgrass, at a rate of 10-12 lbs/1000 sq. ft.
- The remaining 11 courses grow Tifdwarf, Tifgreen 328 or Pee Dee-102 bermudagrass. All of these courses overseed with Poa trivialis, the most popular choice.
If this survey had been done five years ago, it is likely that the percentage of courses not overseeding roughs would have been 20-30%, which is now at 52%, and those not overseeding greens would have been zero. Now, 27% of courses growing an ultradwarf bermuda do not overseed greens. Now is the time to meet with decision makers at your facility, including golf professional, general manager, course officials, etc. Everyone needs to get on the same page with regard to the long-range winter and summer grassing scheme for the club. For the desert Southwest there are several good reasons to suspend overseeding in roughs and ultradwarf greens, and the Green Section agronomists will be happy to meet with you and help refine your plans for overseeding during the coming season.
Brian Whitlark is an agronomist with the Southwest Region of the USGA Green Section located in Gilbert, Arizona.