The first part of May 2026 could be described as darn right chilly, with night time temperatures registering negative numbers.
One of the best steps a farmer can take towards managing resistant weeds is to use multiple effective modes of action in their pre-seed burn off application before pulse and soybean crops. After “the mercury has dipped”, waiting to spray, until the temperatures have progressively consecutively improved, is what it’s going to take to have successful spring burn off applications. It’s very hard to wait, but weeds need to be actively growing before they will take up herbicide. Think, if the cold made the weeds with leaves go “limp”, the pre seed burn off application is going to “skimp” on controlling the emerged weeds.
Here are some guidelines to consult when deciding if the time is wrong for spring pre seed glyphosate and glyphosate with tank mix applications.
When taking the temperature reading 12 inches above ground level, ask the question
Did the overnight temperature get to:
-1 °C to -3°C (after a frost)
Best to hold off spraying, until your field has experienced at least 3 days (72 hours) of good growing weather. By good growing weather, we mean the temperature hit at least +18°C during each day at some point and the temperature didn’t dip below +3°C anytime, during those 3 nights.
#frostyFRUSTRATION
0
Best to wait for 2 to 3 days (48 to 72 hours) of good growing weather, before hitting the field with your burn off application.
+1 to +3
Best to wait 1 to 2 days (24 to 48 hours) of good growing weather, before spraying your glyphosate and tank mix application.
4
It’s okay to spray, pre seed herbicide early that morning.
#go4it