There is a lot of misunderstanding about crabgrass and how to control it. I get lots of questions about this persistent weed every year. This fact sheet should help clear some of it up for you.
- Crabgrass is an annual plant that germinates in spring and dies at the first heavy frost.
- A single large crabgrass plant produces many thousands of seeds each year.
- Crabgrass seeds will germinate each spring when the soil temps reach 55 degrees for 4 consecutive days.
- The most effective method of stopping the weed is to not let it get started. A quality preemergent is your best defense.
- The preemergent must be applied before the seeds germinate. Once the seed has germinated the preemergent will not be affective. The only exception to this is to use Dimension, a commercial preemergent that will kill crabgrass in the seedling stage.
- If you have a lawn service spread your preemergent, be sure it is applied at the correct time. When they run behind schedule, some customers will get it too late.
- Homeowner varieties of preemergents usually start to lose effectiveness in mid-summer.
- Commercial preemergents, such as Barricade and Dimension, will usually last the whole growing season.
- Heavy rains and high summer heat will degrade the preemergent and lower its life expectancy.
- It is ok to reapply a preemergent in summer, but not if you plan to overseed in the fall. It will prevent your grass seed from germinating. If your preemergent is mixed with fertilizer, be sure to apply the correct amount of fertilizer based on the season, grass species, and nitrogen needs for your grass.
This is just a basic guide and there is much more information about crabgrass on our website. Be sure to check it out.