Timing Cultivation and Postemergence Herbicide Treatment

Mark VanGessel, Extension Weed Specialist; mjv@udel.edu

Questions have come in about whether to cultivate first or spray first for weed control. Keep a few things in mind.

● Weeds are easier to control when they are small but consider which option is going to be more effective when weeds get larger;

● Cultivation will control the weeds between the rows but not in the row. Those weeds in the row are the ones you need to base your decision on whether to spray first;

● More often than not, it is better to spray first, then cultivate;

● Delaying the herbicide application allows the crop canopy to expand, which can interfere with spray coverage;

● Weeds emerging after cultivation are going to be much smaller and have less impact on yield (if any impact at all);

● A number of herbicide labels recommended waiting a minimum of 5 to 7 days between herbicide treatment and cultivation.