Seedheads are widely regarded as undesirable in the golf course industry. They add uninviting brown and yellow tinges to the grass, creating unkempt appearances and negatively impacting your golfers’ experiences. Furthermore, they hinder the playability of your course. When seedheads begin to appear, they can add unwanted bumpiness to greens, influencing the roll of the ball and making it more difficult for golfers to determine the speed of greens. And as we all know, there are few things more frustrating than an inconsistent course. As we move into the spring season, the time is ripe for your golf course maintenance team to get a jumpstart on suppressing seedheads and setting your course up for success.
“Simply put, seedheads make turfgrass look unkempt while impeding the ball roll on courses.” – Steve Abler, Wisconsin Territory Manager of Turf Sales & Softgoods
Early spring applications of Proxy, tank-mixed with Primo MAXX, have shown the potential to reduce seedhead formation of annual bluegrass. But due to fluctuations in weather throughout spring, seedhead suppression is highly volatile from year to year, and even from location to location. With this understanding, we must acknowledge that a calendar-based application schedule is not the best way to achieve consistent suppression results. With countless variables to look after, you need a system that is just as adaptable.

Effectively Timing Seedhead Suppression
Dr. Ronald Calhoun developed a model for seedhead suppression application timing for the Midwest that is based on growing degree days (GDD). This model has been the standard for well over a decade and recommends an initial putting green application of 5oz/M of Proxy + 0.125oz/M of Primo MAAX be made when the GDD (Base 32) are between 200 and 500 for optimal results.
Based on Dr. Calhoun’s model, Michigan State University maintains a GDD tracking website which does all of the calculations necessary for timing your seedhead suppression application, as well as other turf applications that are based on GDD. This site allows you to customize the map based on your specific location, and even provides email alerts for when you’re approaching certain GDD ranges. This is a tool that we highly recommend keeping in your back pocket when planning your applications.
In 2016, Dr. Shawn Askew of Virginia Tech’s School of Plant and Environmental Sciences published the results of Poa annua seedhead suppression work done in Virginia, with collaborators from Utah (seen here). The findings show that making a Proxy/Primo MAAX application at least one month prior to the traditional 200-250 GDD target will greatly improve the effectiveness of seedhead suppression. Furthermore, the study found that these applications could be made as early as late-November in Virginia without reducing the efficacy of the treatment. Applications one month before GDD reach 250 are often not practical or possible in the Midwest, so some superintendents have made the choice to add 5oz/M to their snow mold fungicide applications to get it out effectively.
Other Considerations
One common recommendation for suppressing seedheads is to include a leaf spot fungicide in the tank with your seedhead suppression applications. Bentgrass tends to be slow-growing at best in the spring, and applying foliar absorbed growth regulators such as Proxy and Primo MAXX will further reduce shoot growth of the plant. Bentgrasses in areas treated for annual bluegrass seedheads are often peppered with leaf spot and tend to take on a purple and/or bronze cast that is unappealing. These areas are notoriously slow to recover since the regulated plants are slow to replace diseased leaves.
While Proxy is the active ingredient directly providing seedhead suppression in the mix, adding Primo MAXX to your tank will enhance the seedhead suppression activity and reduce the potential for deteriorations in turfgrass quality through thinning and discoloration that may occur when Proxy is used on its own.

Overall, seedhead suppression should be considered an essential part of turfgrass management. The suppression of seedheads helps to ensure a healthy and visually appealing turfgrass, which is critical for maintaining the quality and uniformity of your turf. Moreover, reducing the presence of seedheads will lead to a significant improvement in course playability. By adopting sound seedhead suppression practices, you can create better playing surfaces and enhance the overall enjoyment of the game for your golfers. When developing any course maintenance strategy, remember to prioritize seedhead suppression to keep your course in top condition.
Contact your Reinders Rep today to develop a sound strategy to succeed this spring!
Learn More About Proxy & Primo MAXX
Proxy aids in managing the expansion of cool-season grasses while inhibiting the formation of seedheads in Poa annua. With this solution, there is no risk of an initial shock to your turf, nor harm to plant life.
Primo Maxx is a plant growth regulator that encourages the development of a more compact and robust turf, with greater resilience against various stresses while restricting vertical growth of shoots.
Check out our Turf & Landscaping library to read more help you further plan for the spring season!