Originally Posted by Marcos This suggestion was a mistake on your part. A "pre-m" applied to the lawn will only prevent non-germinated annual weeds. Dandelions are PERENNIALS. O.K. fine..point taken. Pre-M, Dimension, Barricade all have mostly annual grasses and broadleaves on the label...with a FEW perennial broadleaves...mainly the ones that are the more shallow-rooted. But this thread was begun by the fellow talking about dandelions, and suggesting trying to prevent them with a standard turf pre-emergent in February ! That's a different animal ! _______________________________ There is one good pre-emergent for tough-to control perennials like dandelions: Dow's 'Gallery' herbicide. http://www.cdms.net/ldat/ld638005.pdf But the large-scale use of it, in turf at least, just isn't cost-effective for the vast majority of business owners. Gallery is really sort of the "crem'e-de-la-crem'e" of landscape pre-emergent products, that found a niche in certain higher-end, cost-is-no-factor turf situations, ususally on estates, higher-profile cemetaries, etc.