I spray when weeds are fairly small, plan on spraying some fields twice, add fusilade to grassier situations. Kills quicker than roundup. Main thing I have found is that if any left in boom over a period of time the ams heats up and smokes the first 200-400 ft of everythinng. Flush at edge of field before spraying if possible.I really like the system as is gives me an alternative to roundup.