📸: BASF employee/Featuring an agricultural field covered with ice and snow.
Best Temperatures for Herbicides to Kill Weeds:
- 65 to 85 degrees F (Green Light)
- 50 to 60 degrees: slower and less effective weed control (Yellow Light)
- 40's and below: Weed control may be significantly reduced or ineffective. (Red Light)
- Overnight temperature: In general, when overnight lows are below 40 degrees, herbicide applications to kill emerged weeds should be delayed until warmer weather.
📸: BASF employee/Featuring a corn field covered in snow.
Exceptions to the Rules Above:
- Residual herbicides (i.e., soil- applied herbicides) for example, Outlook® Herbicide and Zidua® herbicide, residual component of Verdict® Herbicide and Zidua® PRO Herbicide can be applied successfully when temperatures are below 40 degrees F if they get enough moisture for activation (visit www.reliableactivation.com).
- When daytime temperatures are above 60 degrees, herbicides can be successful even with cooler overnight temperatures.
Systemic vs. Contact Herbicides
Systemic herbicides such as glyphosate, dicamba, and 2,4-D are more negatively impacted by lower temperatures than contact chemistries (e.g., Sharpen® Herbicide, Verdict® Herbicide, and Zidua® PRO Herbicide).
Beware of Cloudy Weather
Cloudy conditions, when coupled with lower temperatures, can further decrease the effectiveness of herbicide applications on emerged weeds (Jhala and Reese, 2017).
📸: BASF employee/Featuring cloudy conditions affecting herbicide application on an agricultural field.
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Endnotes
- https://cropwatch.unl.edu/burndown-herbicide-activity-%E2%80%94-can-we-kill-anything-when-its-cold
- https://www.ndsu.edu/agriculture/ag-hub/ag-topics/crop-production/diseases-pests-and-weeds/weeds/temperature-and-herbicide
- https://cropwatch.unl.edu/2017/low-temperature-and-frost-may-affect-efficacy-burndown-herbicides
Always read and follow label directions. Grow Smart, Outlook, Zidua, Verdict, and Sharpen are registered trademarks of BASF. Copyright 2024 BASF Corporation. All rights reserved.
Always read and follow label directions. The views expressed by BASF employees, Contributing Writers and Guest are their own and do not necessarily reflect the views of BASF. All other trademarks are the property of their respective owners and use of any such trademark does not imply any affiliation with or endorsement by its owner. Grow Smart is a registered trademark of BASF. © 2024 BASF Corporation. All Rights Reserved.
