Why is Crabgrass so difficult to control?
Crabgrass cannot be controlled as effectively after the plant has emerged like broadleaf weeds can. As a result, one needs to rely heavily on pre-emergent treatments for a control program. Unfortunately, a pre-emergent application does not offer complete control. How does a pre-emergent application work? The pre-emergent treatment, when watered into the soil, forms a partial barrier in the top 1/8″ to 1/4″ of the soil. If the sprout, from the newly germinated seed, makes contact with the herbicide in the soil, it will die before emerging above the ground. Why are the results of a pre-emergent application somewhat unpredictable? There are several factors that can reduce the odds of a germinated weed sprout making contact with the herbicide in the top 1/8″ of the soil. They are as follows: • Some of the herbicide dissipates into the air before it is watered into the soil. • The herbicide binds to the thatch and never reaches the soil • Over a matter of weeks, the soil gradually reduces t
