How do I control quackgrass?
Prevention-type herbicides will prevent quackgrass seed from germinating but 1) that isn’t how quackgrass is usually spread (it spreads mostly from root systems) and 2) won’t help you if it’s already established. Quackgrass can have root systems that spread for many feet and can go three feet down. To get established quackgrass out of a lawn (which is what I assume you mean by yard) then you’ll need to completely kill the area and start over. Just diggin it out won’t do it. You can kill the area by putting down an opaque barrier like black plastic for a few weeks then sodding or reseeding or killing the entire area with a general purpose herbicide like glyphosate (e.g. Roundup) as Ostara recommends. It’ll likely take more than one application to kill quackgrass though. Again, sod or reseed. Or just live with the quackgrass. Keeping your regular grass healthy will help give it a competitive advantage over the quackgrass. Make sure it gets enough water, fertilize, lime as appropriate, cu
