We talk about herbicides and their behavior in warm temperatures, but what about cold? UGA Extesion Weed Scientist Dr. Erik Prostko has this to say:
Growers who have sprayed certain POST systemic herbicides (i.e. Roundup, Poast, Select) over the last 15 days are likely to observe slower and/or reduced performance due to the cold weather. When temperatures drop below 50 F, weird things start to happen because plant growth is stalled and physiological processes such as absorption and translocation are reduced. In the past 15 days, most areas in Georgia had 10-11 days of temperatures below freezing (Figure 1). Those temperatures are not very herbicide friendly. Daily low temperatures are expected to be below freezing through Saturday night (Jan 20). Growers with ants in their pants might want to wait until Sunday or later to resume any herbicide spraying that is needed. If a grower has already made an herbicide application during this cold snap, I would suggest that he/she evaluate the situation 10-14 days after treatment and re-treat if needed and if the label permits.
