Luke from San Diego, Ca writes
Certainty is labeled to control quackgrass and but is not labeled for your tall fescue. Unfortunately, there is not a product that will kill quackgrass without also killing the tall fescue. The best treatment is spot treating with a glyphosate product like Roundup QuickPro and then reseeding after 2 weeks.
Answer last updated on: 03/13/2021