Green speeds this spring/summer were really good(faster than last year on average) until around the 2nd week of July. We were able to get them running very fast with rave reviews for member/guest the first week of August, but had to back off with the temperatures and humidity the past two weeks since. There are many factors that go into green speed and each property/course is different. I can only speak for what we do, not other golf courses. We even see huge differences in the Weiskopf and the Devlin greens and the way they react speed wise even when the conditions are perfect.
Factors on slower greens speeds in the past few weeks:
With the drought: We had only received 2" of rain from May 15th thru July 29th. It is nice to be able to control the water and be on the drier side for playability, but the salt content in our irrigation water over time really raised the salinity in the soil. Because the ponds hadn't been flushed since the winter, we were basically watering with salt water. Not a problem for a week or two, but for 2.5 months, the salt in the soil will not allow the plants to take in the water at the rate it needs causing us to have to water more than we would like, slowing down the greens, and making the surface a little bumpy because it is not as firm. There are different calcium and soil conditioner products we apply and spray help flush the soil. Nothing is as good as rain water. Once we started getting rain, the soil was flushed of the salts and allowed the nutrients to become available to the plant. This then caused a surge of growth. On July 30th, when we got 1.9" in 3 hours, the greens had an off yellowish color to them. Two days later they had the darkest green color and were as hairy as you can imagine. This was the release of nutrients that had been bound up in the soil for two plus months.
The heat: Last summer we had 3 days above 90 degrees. This summer so far we have had 23. Poa greens do not like the heat. We have been able to keep them in great shape(slower speeds than normal recently) by limiting the number of times we double cut and roll. The more stress on the plant during these times of high heat, you can lose areas of grass in a matter of hours. We still cut at the same height(.105") as we always do and still cut everyday.
The humidity: The past two weeks have, like I said in my email blast been a "superintendents nightmare." Night time temperatures above 74 degrees for 9 days really effects the plant more than daytime heat. If the plant gets breaks at night they can recover from extra stress, but we haven't had any breaks so we have to baby them through. The humidity being above 70% all day does not allow the plant or the soil to dry out no matter the temperatures. The plant becomes puffy and grows rapidly. We spray growth regulator on greens every 7 days to keep the growth minimal. Right now, the greens are growing out of regulation after 3-4 days and even when they are regulated we are getting way more clippings than usual. On Weiskopf, when the greens are growing normal, we empty our grass buckets 1 time every 4-5 greens. Yesterday we double cut and emptied 1 and half times PER green. We were able to spray our growth regulator(Primo) yesterday and that should really help with the temperatures in the forecast starting Monday at keeping growth at bay. Extra growth causes the greens to become uneven and bumpy as well. Continuing our topdressing program that has been a huge success the past three years will continue to firm up the greens. With 3" of rain and humidity about 70%, the greens will have a soft feel to them.
Going forward, you will notice the greens speeds pick up. Today with getting down to 66 last night, we double cut and rolled Weiskopf and mowed and rolled Devlin. We are always planning many days in advance what we are doing to the greens based of what they can handle. With the growth regulator in place and temperatures and humidity going down speeds will be back to where they need to be. I hate it more than anything to have slower greens(and I take a lot of heat for it), but I also know a period of slower greens in high times of stress are necessary to keep the plant healthy so we can speed them back up and have great faster greens later in the summer and the fall without having burnt out dead spots on them. When I started at Quail in August of 2013, there were plenty of burnt out turf and dead spots on the greens. It took until fall to have 100% coverage again and we have been that way ever since. Please feel free to call or email with any questions.