1. 1. Seeds Begin Germinating in Spring
   Crabgrass seeds typically begin germinating when soil temperatures remain between 55 and 60 degrees for several consecutive days. In Northeast Wisconsin, this usually occurs during the spring, although the exact timing varies depending on weather conditions. Not all crabgrass seeds germinate at once. Additional seeds may continue emerging throughout late spring and summer when warmth, moisture, sunlight, and exposed soil are available.


2. 2. Crabgrass Grows Rapidly During Summer
   Once established, crabgrass spreads outward and produces additional stems, known as tillers. Its coarse, light-green growth becomes increasingly noticeable as Kentucky bluegrass and other cool-season grasses struggle with summer heat. Crabgrass can tolerate compacted soil, high temperatures, and dry conditions better than many desirable lawn grasses. This allows it to spread quickly through thin or stressed turf.


3. 3. Mature Plants Produce Seeds
   As the days become shorter, mature crabgrass plants begin producing their distinctive finger-like seedheads. Even when crabgrass is regularly mowed, it can adapt by producing seedheads below the normal mowing height. These seeds fall into the lawn and replenish the existing crabgrass seed bank in the soil.


4. 4. Frost Kills the Plant—but Not the Seeds
   The first hard frost kills the visible crabgrass plant. Unfortunately, freezing weather does not destroy the seeds that have already fallen into the soil. Those seeds remain dormant through the winter and may germinate when favorable growing conditions return the following spring.

Crabgrass seeds can remain viable in lawn soil for approximately three years. This means one summer of uncontrolled crabgrass can create problems for several future growing seasons. Even when very little crabgrass is visible during a particular year, dormant seeds may still be waiting in the soil for an opportunity to germinate.

Long-term crabgrass control involves more than treating the plants you can see. It also requires preventing existing plants from producing additional seeds and reducing future germination.

Yes. Once crabgrass is visible and actively growing, a pre-emergent treatment will no longer control those established plants. At that point, a selective post-emergent crabgrass treatment is needed.

Proscape’s Crabgrass Erase™ service targets actively growing crabgrass while protecting compatible desirable lawn grasses when applied according to the product label.

Timing is extremely important. Post-emergent treatments are most effective when crabgrass plants are young, small, and actively growing. Larger plants with several tillers or mature seedheads are much more difficult to control.

Our lawn care professionals evaluate several factors before making a treatment recommendation, including:

• Whether the weed is actually crabgrass
• The growth stage of the plant
• The surrounding turfgrass species
• Current temperature and moisture conditions
• Whether spot treatment or broader treatment is appropriate
• Whether a follow-up treatment may be needed

Treatment results may also be affected by extreme heat, drought stress, plant maturity, and the severity of the infestation. For this reason, post-emergent crabgrass control should be viewed as one part of a complete lawn care strategy rather than a guaranteed one-application solution.

Post-emergent treatment controls crabgrass that is already growing. Proscape’s Crabgrass Shield™ pre-emergent treatment is designed to help prevent new crabgrass seedlings from becoming established the following spring. Maintaining a thick, healthy lawn is also important. Proper mowing, watering, fertilization, aeration, and repairing thin areas can reduce the sunlight and exposed soil crabgrass seeds need to germinate.

A thick lawn creates natural competition and leaves less room for crabgrass to become established.

Helpful lawn care practices include:

• Mowing at a height of approximately three inches
• Watering deeply and less frequently
• Relieving soil compaction
• Overseeding thin or bare areas
• Following a properly timed fertilization program

The earlier crabgrass is identified, the more treatment options are available. Allowing plants to mature and produce seeds can extend the problem for several additional years. Seeing crabgrass in your lawn? Contact Proscape to have your lawn evaluated and find out whether Crabgrass Erase™ post-emergent treatment is right for your property.

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