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K-State Turf and Landscape Blog

Tag: establishment

Seeding after Herbicide Application

Posted on by Jack Fry

By Daniele McFadden (recent M.S. graduate at K-State)

With spring in full swing many of you are taking advantage of the warm soil temperatures and overseeding turf areas. Often times we can mistakenly coincide our spring-time herbicide applications with seeding cool-season turf. So, are your new seedlings going to mature and develop if this happens? Research was done over the last two years to evaluate how several herbicides affect the emergence and growth of tall fescue and Kentucky bluegrass when seeded after application.  Following are some takeaways from these experiments.

The good:

  • When dandelions and other common broadleaves start to appear, a standard three-way postemergence broadleaf product containing 2,4-D + MCPP + dicamba (numerous trade names) is often applied. In both the field and greenhouse, we found that seeding tall fescue into an area treated with this herbicide combination was safe on the seedlings, and was comparable to tall fescue growth in areas where the herbicide wasn’t applied.
  • Other combination products used for control of broadleaf weeds were found safe on tall fescue seedlings when seeding was done 0 to 14 days after herbicide application. These herbicides included:
    • Carfentrazone-ethyl + MCPP + 2,4-D + dicamba (SpeedZone)
    • Fluroxypyr + halauxifen-methyl + 2,4-D (GameOn)
    • Triclopyr + pyraflufen-ethyl + 2,4-D + dicamba (4-Speed XT)

The bad:

  • Playing catch-up with yellow nutsedge control? Applying halosulfuron-methyl (Sedgehammer and other trade names) in late summer or early fall for the control of nutsedge could affect your tall fescue and Kentucky bluegrass seedlings if seeding occurs within two weeks of application. Both cool-season grasses emerged in the field with mild chlorotic symptoms that went away within 8 weeks after seeding. However, a closer look at root development showed that seeding tall fescue into soil treated with halosulfuron-methyl significantly stunted development. The Sedgehammer label guidelines clearly state that a four-week delay after application is needed.  Plan your nutsedge control earlier in the summer so it does not interfere with early fall seeding.

The ugly:

  • Did you accidentally apply a preemergence herbicide for crabgrass control before seeding? You might be wasting your seed. Our studies found that seeding tall fescue or Kentucky bluegrass into an area treated with dithiopyr (Dimension) greatly inhibited growth of the seedlings.

Bottom line – reading the label to learn how soon seeding can be done after herbicide application is critical. Labels on some of these products indicate that seeding should be done after a longer interval has passed after application compared to what was observed as required in this research.  Seeding guidelines on labels must be followed; that said, research results from this project provide useful information to herbicide manufacturers and turf managers who may unknowingly seed into herbicide-treated areas.

Evaluating emergence of tall fescue and Kentucky bluegrass when seeded 0 to 14 days after herbicide application in Manhattan, KS.

These research results will soon appear in greater detail in K-State’s 2021 Turfgrass Research Research Report.

***Mention of trade names or commercial products in this article is solely for identification purposes and does not imply recommendation or endorsement, nor is criticism implied of similar products not mentioned by Kansas State University.***

 

Spring cool-season turfgrass seedings – Why they fail

Posted on by jahoyle

(By Jared Hoyle and Ward Upham, KSU Research and Extension)

When we talk about cool-season turfgrass seeding timing I always think the fall.  Well all around town I keep seeing more and more people seeding their lawn this spring.  I don’t want to say you are wasting your time because there are a couple reasons that you might need or have to seed in the spring but most success is achieved if seeding cool-season turfgrass in the fall.

There are several reasons Kentucky bluegrass and tall fescue lawns are better seeded in the fall than in the spring.

These include:

  • Some of the most serious lawn weeds such as crabgrass and foxtail emerge in the spring. Since they are warm-season weeds, they will compete and often crowd out young, tender cool-season grasses during the heat of summer.
  • The most stressful time of year for cool-season grasses is summer, not winter. Poorly established lawns may die out during the summer due to heat and drought stress.
  • A lawn often gets more use during the summer, leading to increased compaction and traffic stress. Young plants have a hard time surviving the high traffic during the summer.
Weed competition when establishing cool-season from seed in the spring.

If an area needs to be established in the spring, sodding is much more likely to be successful than seeding. Sodding provides stronger, more mature plants that are better able to withstand stress and prevent weed invasion.

Establishing buffalograss in golf course roughs

Posted on by jahoyle

(By Jake Reeves and Jared Hoyle, KSU Turfgrass Research and Extension)

Water restrictions and increased interest in sustainability are driving many golf course superintendents to consider new ways to save.  Ironically, one of the best new fits for saving in Kansas is one of the oldest ways around: buffalograss.  Buffalograss (Buchloe dactyloides) is actually the only widely used turfgrass native to North America. Many of the recent cultivars (Sharp’s Improved II, Bowie) grow denser and greener than their predecessors while not sacrificing their drought/cold tolerance, disease resistance, and other great characteristics. Traffic intolerance is one of the largest concerns for many superintendents, but a little traffic management can go a long way especially if coupled with cart paths. While not a perfect fit for every situation, buffalograss requires very little water, less mowing, and minimal nitrogen input to achieve an acceptable stand.

It is these characteristics that have many courses considering replacing their tall fescue roughs with buffalograss.  Once established, the courses could divert the money and time previously spent on their roughs to tees, fairways, and greens, ultimately rewarding a well-played round.

The end product is exciting for many superintendents, as their water bills would shrink. However, going through long periods of closing the course for renovations isn’t appealing to already cash-strapped courses.  Minimizing downtime and maximizing germination success with buffalograss seeding is a must if a course wanted to reduce the financial impact of the process.

We wanted to look at the most effective form of renovation from tall fescue roughs to buffalograss roughs without tilling the soil. This was to allow play to continue as long as possible on the course and keeping the renovation process very feasible for most courses.  Examining 3 different mowing heights and 4 different cultivation practices, our results will provide the most time and cost effective method for end users.

We are comparing a zero cultivation practice, aerification(2x), verticutting(2x), and slit seeding(2x @ 2lbs/M each pass)  against the 3 mowing heights (2.5”, 1.75”, 1.25”).  All cultivation practices except for slit-seeding were broadcast with Sharp’s Improved II buffalograss seed at 4 lbs/1000 ft2.  Traditionally, it is recommended that buffalograss seed be soaked for 3 days, changing the water every day, to encourage a quick germination upon seeding.  However, we did not soak the seed, believing the process not to be practical if a course was truly reseeding all of their rough.

Our results to date have shown that slit-seeding was the most successful method by far with aerification, verticutting, and zero cultivation decreasing in effectiveness in that order.  Slit-seeding mowed at 1.25” and 1.75” reached 100% cover 6 weeks after seeding (WAS) with minimal weed encroachment.  Ultimately, mowing height has had no effect except for a very slight lag in plots mowed at 2.5” compared to the two lowers heights. We hope to continue looking at fescue removal and buffalograss seeding in order to shorten the green cover loss experienced in the renovation process.