Pre-emergent Right After Post-Emergent?

JimmyN – posted 24 September 2002 06:28

Due to a lack of experience and help at the store, I screwed up and applied a post-emergent herbicide when I really meant to apply a pre-emergent. Should I wait to apply a pre-emergent? If so, how long? Thanks.

seed – posted 24 September 2002 15:07

JimmyN, it would be wise to wait.

Even when there is no interaction between chemical #1 and chemical #2, confusion can be caused if they are applied at about the same time. If there is any adverse reaction, you will not know whether it was caused by chemical #1, chemical #2, or their interaction.

I don’t know what kind of turfgrass you have, or which postemergence or which preemergence herbicide you used, and certainly in some cases it makes good sense to follow a postemergence with a preemergence, but if it’s a new situation for you, the most that I would suggest is to apply a test strip before applying a broadcast.

Phil