How do pre em herbicides work?

[colhonk]

Won’t be cheap.

Current ones arn`t cheap when they do nowt

 

[alomy75]

Current ones arn`t cheap when they do nowt

So true. But without an unsprayed strip through the blackgrass patches…how will we know how bad it ‘could’ have been

 

[Oat]

Several post em herbicides can have both contact (kill weed plants they hit) and residual activity (kill weeds via root uptake, like pre em herbicides).

Some post em herbicides like Atlantis won't say they have a residual effect, but they do