Time is running out, along with daylight and high soil temperatures, for those still trying to recover from the turf losses caused by this summer’s heat wave. I’m amazed that some courses are just starting to seed into thin and bare areas on greens and expect full recovery before winter arrives. After all, the weather has not cooperated all season, so why should it start now?
Granted, soil temperature are still pushing upper 60’s during mid-day and you might see green bentgrass fuzz on a freshly-seeded site within 10 days or so, if (and a BIG if) the mild weather holds up and nights don’t become too chilly. Small, isolated dime- to quarter-sized areas of thin turf can recover when bentgrass creeps in from the borders, but large bare areas need seed, heat and time. Why the pessimism? Do the math. Let’s say you began the process the day after Labor Day.
Seeding bare area until you see green fuzz------------------------------------ 10 days
Fuzz grows high enough to mow a few times--------------------------------- + 10 days
Several topdressings and mowing height adjustments
to encourage turf to fill in between seed lines or aeration holes------------- + weeks
This is assuming that you are taking the problem green out of play and raising the mowers to at least 0.180” and watering the seedlings several times a day and not getting the frost that is in the weather forecast for much of the upper Midwest. The bottom line is – don’t count on a mid to late September seeding with bentgrass to do much good this season, especially when you continue to mow at or below 0.125” and keep the green in play. Think of that huge dead spot as a new green and you will realize that a green seeded during mid September will not be ready to play until June or July of next season. A winter cover might not be a bad idea, although the most benefit, with respect to increasing soil temperatures, will occur next spring.
No doubt, the outlook is pretty bleak for courses that lost grass on predominantly bentgrass greens. A better option may be to start patching the injured areas with sod from the nursery or the practice putting green right now if you don’t want to be patching with sod next spring. Short days, long cool nights, low sun angles and plummeting soil temperatures are limiting your bentgrass options during a year when Mother Nature has a chip on her shoulder.
Some hope remains for thin. bare Po annua greens that typically have plenty of live seed already in the soil. It’s not unreasonable to expect a fair amount of recovery to occur on Poa greens during late September and October if we are lucky enough to experience a few weeks of Indian summer and some timely rainfall to compensate for the times we forget to irrigate weak greens during long periods of cool dry, weather.
In a nutshell, this has been a very difficult season that many superintendents want to forget… but one they will likely remember for a long time.
Source: Bob Vavrek, email@example.com or 262-797-8743