The next 30-45 days are critical to the short term health of our bentgrass/poa-annua greens. Right now our surfaces are in good shape. The concern I have about our wet green surfaces and profiles has me concerned enough to write this blog. I don't see anything at this time except for the black algae that pops up when the weather conditions are right but the overall wet condition of our soil profile and future predictions for more wet weather is not the place we want to be going into the heart of the warmest time of the year.
Of course, ball roll out I know is not what you have wanted to see over the last few weeks nor have I liked what we have been able to provide. But doing anything differently could have severely compromised the health of our greens for months to come. A combination of summer heat and excessive moisture can lead greens down a not so great path. You do everything perfectly, provided all the proper cultural practices to your greens but weather sometimes just wins. This season we hope we've made all the proper moves to offset our negative weather conditions. Our temperatures have been average for the most part but the humidity and soil moisture content has been excessive in June with an all-time record rainfall. We've started out July with wet and soft greens and the prognosis for the upcoming month is not too good to help firm our surfaces.
The following cultural practices over the last month has protected our surfaces from excessive wear and tear before the potential of the hottest part of the year July/August has arrived.
- We've skipped mowing on days when excessive moisture could compromise the health of our greens. I don't think I have ever skipped more mowing in June than I have this season. Of course record rainfall will cause that. I'm not speaking in the 3-4/10" range, I'm talking 1-2" in the last 12 hour range.
- We needle tined our greens at the end of May and hydrojected them at the end of June in an effort to keep them open and pushing moisture through and drying them out when it was not raining.
- We have not top-dressed as often but have gotten a few topdressings down to help reduce wear damage and cover the crowns of the plants.
- Chemical applications have been made as timely as possible between rainfalls. On some occasions I would only load 1/4 tanks to reduce negative impacts from the weight of the machine when we applied products to our greens.
- This is one of those seasons that attempting to get excessive ball roll out artificially is very dangerous for our turf. As conditions dry, we bring out the roller and smooth our surfaces which helps to improve ball roll out. The biggest problem we have is that the grass plants are so plump and full of moisture which causes friction and slows ball roll. There is not a lot we can do artificially because the surfaces have been so wet. Double cutting greens is not the answer, especially when they are already soft.
- Applied wetting agent and growth regulators to move moisture through the profile and reduce top growth. Of course reducing top growth is difficult when you had to skip mowing 3 days during a 7 days period. The guys have been double dumping their buckets on greens for a number of days.
I've attached a couple of prediction maps to help illustrate the predictions for the next month. The first map is for rainfall. As you can see, Missouri being in the center of the country for those that are geographically challenged and sitting right on top of us is a kidney shaped dark green blob that is given the letter B which stands for above normal precipitation for the month. With the predicted rain of 2-4" coming in the next couple of days, we could be close to our average monthly total for the month or 4.11" before we are 10 days into July. This is not a good sign for us. Excess moisture during heat leads to soft conditions which we've already experience for the last month or more and can lead to many stresses under the surface of our greens:
- Excess moisture increasing soil temperatures in greens reducing root growth.
- Excess moisture increasing CO2 and decreasing Oxygen which is most important for root survival.
- This condition encourages fungi in the soil and reduces good microorganisms which improve plant health.
- Mechanical damage from mowers, foot traffic and ball marks are larger. In the end, seriously affects ball roll out.
- Some disease activity could be delayed until dryer conditions occur such as summer patch which roots are infected but plenty of moisture will delay or mask the disease until dry conditions occur.
- Also root pythium diseases can be problematic because you have to water chemicals to the rooting area but you are already wet from too much rain. These type diseases have already been showing up in greens since spring and become more troublesome as summer rolls along.
One of the things we are seeing is below normal temperatures for July. I guess if we were too wet, I would prefer that temperatures be below normal than above normal under these conditions. Temperature stress is taken out of the package which is a good thing. Roots systems could stay stronger which will help the plants offset other stress over the next month or two. Hopefully, the rain will be less frequent. Maybe we have an above average amount but the temperatures stay below normal and help you get out more frequently than you normally would during a hot July.