Search All Resources

Maximize Your Spring Ethephon Application

January 19, 2021 | Categories: ,
poa annua seed

Ethephon is a highly effective PGR for Poa annua seedhead suppression on cool-season turf. Use the information below to maximize the effectiveness of your spring ethephon (Proxy) sprays. 


An effective ethephon program involves making the first application in late fall, after the final mowing, and then completing two applications in the spring, adding in trinexapac-ethyl/Primo MAXX. The following applications are recommended as the best method for you to manage seed head suppression this upcoming spring with ethephon.

Spring Application 1 (Traditional Application)

  • Review GDD Tracker

  • Check for the boot stage of the Poa annua. The seedhead can be felt down in the sheath of the plant but cannot be seen.

  • Keep a look out for the initial sign of forsythia bloom

Ethephon @ 5 oz/M rate
Primo MAXX @ .125 oz/M rate

Spring Application 3 (2-3 weeks later) Ethephon @ 5 oz/M rate
Primo MAXX @ .125 oz/M rate

To allow the greatest absorption into the turf, do not water in ethephon. For the best results, allow your spray to dry and delay mowing for 1-2 days. Adding in a Bayer Stressgard fungicide is an excellent combination that gives plant health benefits.

What should you do if you missed the fall application? 

Reference the traditional ethephon program for Poa annua seedhead suppression: a minimum of two applications in the spring, normally one month apart. Base the timing of the applications on the Poa Annua plant boot stage, the first sign of forsythia bloom, the growing degree day (GDD) model, and the temperature in your area.

Additional Ethephon Applications

Some Superintendents are making additional ethephon applications during the growing season. There are a few benefits of making additional ethephon sprays past the seedhead suppression window. They include overall plant health, clipping and growth reduction, and sustaining reliable green speeds. The ethephon label permits a maximum of 30 ounces per 1000 sq ft per year, six applications at the 5 ounces per 1000 sq ft rate.

Please contact your Advanced Turf sales representatives for further discussion on products, rates, and timing.