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January 30, 2023

Poa annua Seedhead Suppression

Spring seems to always come early when you are managing Poa annua seedheads and if you miss your timing it becomes challenging to get a handle on the seedheads all season resulting in bumpy putting surfaces.

Poa annua graphic

Quali-Pro Ethephon 2SL has been the go-to product for seedhead suppression as it works by initiating ethylene production in the plant which in turn suppresses seed head production in the plant.  Applying Quali-Pro Ethephon 2SL before seedhead production in vital for success.  In recent years many turf professionals managing mix stands of turf with Poa annua have been successful with the initial ethephon application added with preventative snow mold products in the late fall. Studies have proven on average a 25% improvement of seedhead control with the additional late fall application of ethephon versus a traditional program with two applications in the spring.

Ethephon 2sl CTA


Using a growing degree day model is an effective way to predict and time seedhead suppression on Poa annua the following season. To effectively use a growing degree day model, begin adding degree days starting January 1st with a 32-degree threshold. There are multiple sites online that track GDD based on your geographic location.


The trigger for the spring QP Ethephon 2SL application is 200 GDD32 at 5 floz / 1,000 ft2 followed up with one additional application at 5oz/1,000 ft2 in 3 to 4 weeks to complete the program.  It is advised to tank mix Quali-Pro Ethephon with Quali-Pro T-Nex to balance the turf regulation with the second spring application.


Timing is very important when trying to suppress seed head production in Poa annua. The late fall application of QP Ethephon will add flexibility to the spring application, although two spring applications are advised. With the addition of QP Ethephon to your agronomic program the product will ensure a tighter canopy of turf and eliminate large Poa annua seedheads resulting in smoother putting and healthier playing surfaces.


If you have any questions or need help setting up your program this spring, please contact your local area Quali-Pro Representative.


Shannon Slevin

Northeast Territory Manager

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