Hi, I went to the local Lesco dealer and asked them for pre-emergent and they gave me Dimension 13-2-5. I am looking to use this on my mulch beds before I lay the new mulch down to prevent weed growth. Is this the correct application of this? By reading the bag it seems like it is used for spreading on the lawn and not mulch beds. If this is not used for beds than what should I get for pre emergent in my beds? Thanks!!!