When is it recommended to apply a post-emergence herbicide?

Applying a post-emergence herbicide is most effective after both the desired vegetation and the weeds have become established. This timing allows the herbicide to target the weeds that are actively growing while minimizing the risk of harming the established plants you want to keep.

When weeds are visibly present, the herbicide can more effectively penetrate the leaf surfaces and enter the weed's system to disrupt growth. The desired vegetation must also be robust enough to withstand the application, ensuring that it does not incur damage from the herbicide.

Applying a post-emergence herbicide before the weeds appear would not be practical, as these products are specifically designed to control actively growing weeds. Similarly, targeting only seedlings may not address larger or more established weeds that could be competing for resources. Lastly, applying herbicide before planting new vegetation is not advisable, as the product could affect germination and establishment of the new plants.

In summary, the recommended timing for applying a post-emergence herbicide is indeed after both the desired vegetation and weeds are established to ensure effective weed control without harming the plants you wish to protect.