Cool Start to August
The blues may be gone for a while, which ironically can make turfgrass managers in summer sad. A cool start to August produced temperatures 2-3 degrees below normal for the month in much of the region. Lows in the low 60s or even high 50s gave cool-season turfgrasses a much needed break and provided some natural fungicide for diseases like brown patch and Pythium. Some superintendents even used the break as an opportunity to aerify putting greens, and some fertilizer and even seed was put down on some lawns. This break unfortunately seems over, as a return to summertime temperatures are expected next week. Fall forecasts indicate a warmer than normal pattern for much of the U.S., hopefully not as hot as last year which had September highs consistently in the 90s. (click here to view last year's report). On the bright side, we are in the back half of August and day length is getting shorter, (over an hour shorter than mid-June) so stress periods will be shorter.
The cool air mass colliding with hot summer air produced considerable instability and heavy rainfall events for the middle and northern portions of the state. A terrible derecho event devastated Iowa with 100+ mph winds, wrecking over 10 million acres of crops and leaving many homeless and without power. In St. Louis, 5-7 inch downpours produced heavy flooding and severe localized damage to turfgrass facilities. Both urban centers of KC and STL are 3-5" above normal precipitation over the last 30 days, producing an "owl eye" appearance to the precipitation map (http://climate.missouri.edu/mcw/). Southwest Missouri has had significantly less rainfall, at 1-2" below normal. Into next week, little to no rainfall is expected in the region which will be a blessing for those involved in rebuilding efforts.
Heavy Rains for STL
Keep an Eye Out for Gray Leaf Spot on Tall Fescue
Summer Patch keeps rolling in
Anthracnose hits bentgrass in cool down.
The Yin and Yang of Soil Moisture
As we enter into the final portions of summer and into fall, many homeowners and turfgrass managers may be looking at lawns and other cool season turfgrass areas with a bit of angst and a "come on, really?" attitude. After a season of stress, August is the month cool season grass is at its worst - ratty and subject to diseases and weed infestation. This being said, fall is on the horizon and applying a bit of rejuvenation crÃ¨me at the right time do wonders for our lawn's appearance.
In this vein, SSSS is an acronym that could suit September, standing for "Spread Seed in September with Sustenance". Since it's wise to check acronyms these days, my search finds the quadruple S only stands for "Secondary Security Screening Selection", which at most is inconvenient and not incendiary. If you double up to "Ssssssss", however, a 1973 horror film claims the title, and after watching the brief trailer I suggest anyone with ophidiophobia to skip this one.
The quality of lawns lies in the number of turfgrass plants creating a uniform dense turfgrass sward. Therefore, providing a stressed out or declined lawn with a solid September overseeding is a sound and perhaps most effective method of rebuilding quality. Many homeowners have this unrealistic expectation that an established lawn will persist into infinity, while at the same time trading out every other plant in their landscape, including trees on occasion. In the wildly swinging climate of the Missouri transition zone, the expectation is perhaps farthest from reality. Also remember that our most robustly used species, tall fescue, is a bunch type plant with no stolons and no rhizomes to creep into bare spaces. Last but not least, seed is organic!
Overseeding tall fescue at 4-5 lbs of pure live seed (PLS) per 1,000 sq ft is a solid route to recuperation. At this time of year, my suggestion for brown patch damaged areas or other thinned areas is to consider putting the effort into this arena rather than into pesticide applications. Along with this, a full pound of N per 1,000 sq ft is also suggested in September. Other nutrients and potential pH manipulation should be applied based on a soil test, and right now is a good time to assess those needs. A core aerification or power-raking (if not done in a last few years) is a great way to start the whole process, but these practices shouldn't be a prerequisite or impediment to overseeding efforts.
One fly in the ointment could be weed control. Crabgrass has been prevalent this late summer, and in some instances has even broken past spring preemergent applications. With frequent rainfall events, nutsedge with its proclivity for wet feet has also been troublesome this year. Selective herbicides such as quinclorac for crabgrass control or topramezone for bermudagrass suppression carry little to no restriction for application prior to seeding. Halosulfuron or sulfentrazone targeting nutsedge, however, requires four weeks between application and seeding. Read the labels carefully and if in doubt consider spot applications of a non-selective herbicide such as glyphosate 2-3 days prior to seeding.
Last but not least, remember to measure your area prior to seeding, fertilization or any application of product, and calibrate accordingly. As one of his last contributions in an illustrious career, Dr. Brad Fresenburg constructed a lawn fertilizer calculator web application - http://agebb.missouri.edu/fertcalc/. While geared towards the homeowner, lawn care operations or any turfgrass manager may find this useful for assessing the area of several properties with the google maps calculator and utilizing the easy to use interface to determine fertilizer needs. As an added trick, if you add the seed germination % in as one of the nutrients the amount of pure live seed needed for an area can also be easily calculated.