Spring Weed Management Tips for Better Herbicide Results

By Blake Jackson

As temperatures rise and daylight hours lengthen in early spring, weeds begin growing rapidly, often outpacing crop planting schedules.

According to Penn State Extension weed specialist Dwight Lingenfelter, delaying weed control until planting can make management more difficult and reduce herbicide effectiveness.

Early-season weeds compete with crops for moisture and nutrients while also interfering with planting operations, making timely control essential.

Applying herbicides earlier in the season commonly referred to as early preplant (EPP) or early burndown can significantly improve weed management. Smaller weeds are easier to control, especially when they are under six inches tall and still in the vegetative stage.

Herbicides such as paraquat tend to perform better on small weeds and are less affected by cooler conditions than glyphosate.

However, herbicide activity generally improves when daytime temperatures reach the 50s and nighttime temperatures remain above 40°F. After cold periods, waiting for several days of warm, sunny weather can enhance results.

Using the correct adjuvants is also critical. Products like AMS can boost glyphosate performance, while specific combinations are required for other herbicides.

Proper spray coverage is equally important, particularly for contact herbicides, which rely on thorough leaf coverage to be effective. Applying at least 15 to 20 gallons per acre can help ensure better distribution.

Tank mixing herbicides can improve control across multiple weed species but may introduce challenges. Some combinations can reduce herbicide performance, requiring rate adjustments to maintain effectiveness.

Additionally, applying both burndown and residual herbicides too early may shorten the duration of residual weed control, leaving crops vulnerable later in the season.

Splitting applications using burndown herbicides early and applying residual products closer to planting can maximize effectiveness.

This approach also allows for higher herbicide rates and expanded product options, leading to improved early-season control and better long-term crop performance.

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