One question that we sometimes are asked is “Why do you start your application season so early? The grass is not even growing yet so isn’t this pointless?”

Everything that we do in lawn care has some kind of timing requirement involved that will help determine when and what products can be applied to the turf. Air temperature, wind speed, time of year, and soil temperature, are a few things we monitor to make sure your applications not only are effective but efficient on your property.

Crabgrass preemergent requires early application for the best results. Soil temperatures are closely monitored to ensure the right product is put down at the right time. For purposes of this blog, I will use the trade name of the product to try to keep it less confusing. With that, let’s jump into it!

Crabgrass can begin germinating when conditions are right and will continue to germinate through the summer months. Known as a late summer annual, we usually see germination begin in April. If left untreated, one square foot of crabgrass can product 10,000 seeds. Proper application of a quality preemergent is required to ensure the best control, however, other factors such as mowing height, irrigation, turf density, and fertilization schedules all can improve the efficacy of the preemergent product applied.

If timing is so important, why do we begin our season in late February? Easy! The product needs to be on the lawn and irrigated into the soil to be active. Would it be ideal to apply a preemergent a few days before the crabgrass germinates? Absolutely. Is it realistic? Absolutely not! Many crabgrass products contain active ingredients that stay working in the soil for up to 6 months. A treatment we make on March 1st can still be effective in August! Beginning our treatments early allows us to ensure that the product can be watered into the soil, usually through rainfall, and be and remain active during the growing season.

There can be some crabgrass that does germinate during the growing season. We call this “Breakthrough.” This can and usually happens along edges, corners, and thin areas in the lawn. Areas that can see lot of traffic can break down the chemical barrier and crabgrass can “breakthrough” in those spots. A proper post emergent application is required to be made but the earlier it is caught, the easier it is to control.

Crabgrass applications also limit when you can reseed a lawn. A product containing prodiamine usually has a reseeding restriction that states “Wait 4 months before seeding following and application” while an application of Dimension may state “Do not overseed within 3 months of application.” Whatever product you use, make sure you consult the label for exact product use restrictions. These restrictions go further than just reseeding time but also turf grass that it is safe to be applied over.

Equally important to a successful crabgrass application is correct use rate. Oftentimes we see people try to save a few dollars and try to cut back on the amount of product applied to their lawn. Unfortunately, a lot rate application for a preemergent herbicide can create more work down the road if you do not properly plan ahead. Lower rates may be acceptable if a split treatment is planned. That means that you split 1 application into 2 but use the same total amount of active ingredient as if you were only making one treatment. This can be confusing and cause issues if soil temperatures jump and the preemergent herbicide you selected for the first 1/2 of the application do not have any post emergent activity.

For our company, we typically only focus our treatment schedule to have 1 full application for the crabgrass preemergent. As we move through treatment route, we monitor the soil temperature and lawns in general. Once we feel like we are getting close to germination, we switch from a strictly preemergent crabgrass product to product that has both pre and post emergent control.

I only discussed two different product names above but there are several different products on the market for crabgrass control. If you are making the application, be sure to do your research and select the best product that is labeled for your lawn. Timing of the application, turf type, soil temperature, application method, and amount to use are all crucial in ensuring you get the best results.