Should I use herbicides when establishing turf at this time of year?
The scars of winter are easily recognizable now as there has been active growth for few weeks in Southeast NY. Seeding of damaged areas or turfgrass renovation in the Spring during intense weed pressure periods raises many questions. There is no question about competition, as winter annual weeds are actively growing and flowering, annual bluegrass is surging, and perennial broadleaves and even summer annuals will be germinating in the next two weeks. Assuming ideal soil preparation or renovation of an existing turf site to receive seed, purchasing quality seed with little to no Poa tivialis (a growing concern in the Northeast US), and ability to supply water-dealing with weed pressure is a top concern for successful establishment. New reduced-risk chemical technology is available for pre and post plant weed management. Tenacity (mesotrione) is a pre and early post selective herbicide that can be applied at and after seeding for pre-control or post control of many grass and broadleaf weeds. Pylex (Topramozone) also a HPPD-bleaching herbicide like Tenacity can be used at seeding but you must wait 28 days until after seeding as young seedlings are susceptible. A third option is to wait until significant seedling emergence and apply Square-One (Quinchlorac plus Carfentrazone) to newly emerging weeds with wide safety to many cool season turfgrass. Consider these options to give your turf a competitive advantage. From Cornell’s Dr. Frank Rossi’s blog, ShortCUTTS