Too often, spring burndown programs are decided based on what’s left over in the chemical shed. While that may make economic sense to a grower, it might not be the best recommendation from a retailer.
After your customers have stored away the combine, they may be thinking of winter as a time to relax and let things settle. But winter provides a good opportunity for them to scout for weeds and learn what they can from their fields. And it’s also the perfect time for you to begin having conversations with them about herbicide selection, application timing and tank-mix rates for burndown recommendations they might want to consider come March or April.
Start with the weeds that are already there
Growers’ first priority should be determining which weeds are already present in their fields. They should look for winter annuals such as marestail, henbit and field pennycress, but they shouldn’t stop at identifying the species. Growth stages can be just as important when determining the appropriate control strategy for a spring burndown.
For example, marestail burndown may be relatively straightforward when plants are still in the small rosette stage, while larger or bolting plants may require adjustments in herbicide rate or tank-mix partners.¹
With that kind of detailed information from your customers’ scouting reports in hand, you’ll have a strong basis for discussing herbicide selection, rate and tank-mix partners before spring burndown application decisions are made.
Let weather conditions help determine the timing
Temperature can have a major impact on how effectively a spring burndown program performs. Both contact herbicides, such as Sharpen®, and systemic products can be less active at lower temperatures. Cooler conditions slow weed growth and metabolism, which can reduce herbicide activity. For systemic herbicides such as glyphosate, 2,4-D and dicamba, slower plant growth can also reduce herbicide uptake and translocation throughout the plant.²
Optimal conditions for most herbicides are typically when temperatures are 55 F to 70 F during the day. However, if the nighttime temperatures will be below freezing, your growers may be better off waiting until temperatures are around 40 F for several nights.³
That means they won’t be able to rely solely on a calendar. A warm afternoon following a stretch of cold nights isn’t necessarily the same thing as spraying actively growing weeds under consistently favorable temperatures.
Account for what is covering and surrounding the weeds
Winter field conditions can also influence how well a spring program performs. Heavy crop residue can prevent spray droplets from reaching their intended targets and reduce coverage on emerged weeds. Additionally, soil moisture can affect how residual products activate and move into the weed germination zone.
Customers’ reported field conditions can help you decide whether to recommend adjustments in coverage, adjuvants or residual chemistry. When recommending a burndown herbicide with residual, consider any weeds already present and also the field conditions that may influence residual performance after application.
Winter scouting and field data don’t automatically tell growers which herbicide to reach for. But it gives them the questions that your expert advice can help to answer.
These four important questions will guide your preseason burndown conversations with growers:
- What weeds are present, and how far along are they? This helps determine active ingredient, rate and tank-mix needs.
- What temperatures are expected around application? This helps determine whether conditions are favorable for spraying or if timing should be adjusted.
- What are the residue and soil conditions? This can influence spray coverage and the residual strategy.
- What has happened in this field before? Previous control failures and known resistance issues can help steer product selection and program intensity.
The best spring burndown recommendation isn’t necessarily the program that worked last year. It’s the one built around what is happening in that field now.
Winter gives growers time to scout, gather information and talk through options with retailers like you before planting-season urgency sets in.
Experts are available to help you make better herbicide recommendations for your growers. Reach out to your nearby extension office agent or a seed company professional like your regional BASF representative.
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Endnotes
- Jha, Prashant, Meaghan Anderson, and Ramawatar Yadav. “Considerations for Spring Burndown Programs for Weed Control.” Integrated Crop Management, Iowa State University Extension and Outreach, 6 Apr. 2021. https://crops.extension.iastate.edu/post/considerations-spring-burndown-programs-weed-control
- Lingenfelter, Dwight. “Fall Weeds: Burndown and Control in Cover Crops.” Penn State Extension, 7 Oct. 2025. https://extension.psu.edu/fall-weeds-burndown-and-control-in-cover-crops
- Werle, Rodrigo, et al. “Watch the Temperature Forecast for Burndown Herbicide Application.” South Dakota State University Extension, 11 Apr. 2023. https://extension.sdstate.edu/watch-temperature-forecast-burndown-herbicide-application
