Brad from Cameron writes
I have applied 2-4 d for weeds and would like to use Tenacity as a preemergence for crabgrass
Tenacity Herbicide can be used on a lawn that 2,4 d or other herbicides have been applied to safely as long as you follow label instructions and apply it evenly. Tenacity will only last about 30 days as a pre emergent compared to other pre emergents on the market that will last 3-4 months. Tenacity is mostly used as a pre emergent in the spring or fall when customers are over seeding their lawns with a cool season grass to fill in bare spots, as its one of the only products that can be used at this time without harming the seed. If you are not seeding, you may want to consider a longer lasting pre emergent or one that covers a wider range of weeds than the Tenacity does, like the Dimension 2EW or Pendulum 2G for instance. If using Tenacity as a pre for crabgrass, you want to put it down at or just prior to your soil temperatures reaching 55 degrees in order to be effective. If soil temps have already progressed past 55 degrees your pre emergent will not do much to stop the weeds.
Answer last updated on: 05/07/2021