Preemergent herbicides

Preemergent herbicides prevent the germination of seeds by inhibiting a key enzyme. In some areas of the world, preemergent herbicides are used to prevent crabgrass from appearing in summer lawns.[1]

Contents

Brands

Brand Ingredient Prevents Notes
Pendulum (herbicide) pendimethalin crabgrass
Surflan oryzalin crabgrass
Dimension (herbicide) dithiopyr crabgrass [2]
Barricade (herbicide) prodiamine crabgrass [2]
Tupersan® siduron crabgrass

Crabgrass

Preemergent herbicides must be applied at a critical time. If they are applied to the soil too early they get washed too deep into the soil by rainwater. If they are applied too late the key enzyme inhibited is no longer active. Depending on where you live, one rule of thumb is to apply when the local forsythia blooms are wilting.

References

  1. ^ Wright, Robert (April 20, 2010). "The Dandelion King". New York Times. http://opinionator.blogs.nytimes.com/2010/04/20/the-dandelion-king/. Retrieved 2010-04-21. "'Pre-emergent' herbicides are laid down more than once in the spring (mixed in with the fertilizer) to sabotage the germination of crabgrass, dandelions and other undesirables." 
  2. ^ a b "Time is right to prevent crabgrass from sprouting". Osawatomie Graphic. April 7, 2010. http://www.graphic-online.com/201004078335/opinion/columns/time-is-right-to-prevent-crabgrass-from-sprouting.html. Retrieved 2010-04-21. "Most of the products that prevent crabgrass contain Dimension (chemical name — dithiopyr) or Barricade (chemical name — prodiamine). Both of these chemicals work well and are long-lasting, so they stop crabgrass throughout the summer." 

See also