[Wirk Karl]

Certainty can be pretty effective against Poa annua, especially in warm-season grasses like bermudagrass or zoysia. It's not a total kill in every case, but with the right timing and multiple applications, it can do a solid job thinning it out. Just make sure temps are within the safe range and follow up with a pre-emergent to prevent new growth. Also, results can vary a bit depending on your region and turf type.

 

[Wirk Karl]

I think you’re on track with using it in the first round as you suggested, @ArTurf. It should also work well for breakthrough control. Based on the label, the best results are generally seen when applied in the early growth stage and before tillering, so I’d say that aligns well with your approach.