As temperatures warm, turf weeds should be one of your top concerns. The more opportunities you give turf weeds to thrive, the harder it could be to reduce future problems. You can reduce the issue by using both pre-emergent products and cultural controls. When combined, it can reduce turf weeds and keep turfgrass looking lush and healthy.
Read further to learn more about using both pre-emergent herbicides and cultural controls to help you in the fight against turf weeds.
Often the use of pre-emergent herbicides is the first thing you might think of to combat turf weeds. When applying these products, it’s important to understand some basics. Below are the top things you should consider before using a pre-emergent product.
You should apply pre-emergent products during early spring, but it can vary based on climate and geographical region. For example, in warmer parts of California and Arizona, January through March are ideal times to apply whereas, in colder regions with longer winters, this can range anywhere from March through May depending on the growing season.
Regardless, it can be hard to determine an exact day for you to apply a pre-emergent. Overall, soil temperatures will be the best indicator. Checking with your local university extension is also a good way to know the best application timing for each region.
Applications of pre-emergent products typically have an effectiveness of 6 to 8 weeks. Relying on this number is not ideal though, since the applied product can lose efficiency and not work throughout its lifetime. Therefore, you should continue checking soil temperatures to ensure an application is closest to the appropriate time. Applying at the correct time not only is efficient but also less wasteful, since the product will be at its full potential.
Before you apply any pre-emergent products, it is important to check weather conditions. Do not apply when expecting heavy rain to avoid dilution, leaching, and runoff. After you use your pre-emergent product, apply a 1/2 inch of water to the turfgrass. This will help the product reach the seeds within the soil, ensuring it blocks germination.
It is best to confirm the exact amount of time or water needed for the product by referring to the product label. Some products might indicate at least waiting 1 to 2 days after application due to the active ingredients within the pre-emergent and how they react. (example below from BEST® ONE-SHOT™ which also includes a post-emergent component, further adding to irrigation requirements for optimized weed control).
The effectiveness of pre-emergent products can also change based on the amount you apply. To ensure proper application always refer to the product’s label. The label will give directions on the amount needed and any other special instructions (e.g., calibration settings, when to apply after overseeding, and any ornamental landscape details).
Follow all application instructions carefully, as an over or under-application of a pre-emergent could cause issues. Not only is overapplication wasteful and a label violation, but it can potentially damage the turfgrass. And although underapplying might seem like a good idea to help save you money, doing so could reduce the efficacy of the active ingredient in the pre-emergent, resulting in future costs to combat the issue.
Remember, Federal and State laws prohibit the use of herbicides outside of the scope of their label to protect applicators and the environment. Following the directed rates and timings provides the proper dose needed while also helping to minimize the possibility of harm to you or the surrounding environment.
Pre-emergent products are a great tool for keeping pesky turf weeds in check, but adjusting your landscape program can make an even bigger difference. Below are a few cultural practices that can help your turf naturally fight off weeds.
When you continually and appropriately provide fertilizer, your turfgrass is more resilient, reducing the chances of turf weeds competing for similar space. According to Penn State University, “Inadequate fertilization lessens the competitiveness of turfgrasses, resulting in reduced density and subsequent weed invasion.” To reduce this issue, proper fertilization can help improve turf vigor and provide for lush growth, making it harder for weeds to thrive. Therefore, it is important to have routine soil tests and ensure the turf you manage is at its best all year round.
One of the easiest ways you can help reduce turfgrass weeds is by changing how you water. Infrequent and deep watering can help turfgrass grow deeper roots. Not only could deeper roots aid in competing for space against weeds, but they might also help during periods of drought.
According to Penn State University, “As turf grows in height, and in density, it is shading out the sun from reaching the soil. As you know, weed seeds need proper temperatures and sunlight (along with water) to germinate. If sunlight is not penetrating the turf canopy, many weeds are unable to germinate, allowing for the turf to grow better. Studies have shown that increased mowing height alone reduces weed pressure significantly, even in the absence of pre-emergent herbicides.”
Increased soil compaction creates an unfavorable environment for your turfgrass to thrive. Because of this, weeds have less to compete with and are more likely to form. This is why regular aerations are important once or twice a year. It is recommended to use a pre-emergent herbicide after this process since some weed seeds might be present in the soil cores lifted out during aeration.
Preventing weeds in turfgrass requires a combination of smart practices. By applying pre-emergent herbicides at the right time and following proper application guidelines, you can stop weeds before they take hold. Pairing this with cultural controls—such as proper fertilization, deep watering, maintaining the right mowing height, and aeration—creates a healthier, more resilient lawn that naturally suppresses weeds. A proactive approach now can save time, money, and effort in the long run, keeping your turf lush and weed-free throughout the season.
For a complete list of pre-emergent and fertilizer products that can help you combat weeds this season, contact your BEST® sales representative or local BEST® distributor today.
“Control of Summer Annual Grass Weeds in Turfgrasses.” Penn State Extension, 1 Jan. 2022, https://extension.psu.edu/control-of-summer-annual-grass-weeds-in-turfgrasses.
“How to Manage Pests.” UC Healthy Lawns-Irrigation: How to Water, https://ipm.ucanr.edu/TOOLS/TURF/MAINTAIN/irrhow.html.
“The Impact of Mowing on Weed Pressure.” Penn State Extension, 11 June 2015, https://extension.psu.edu/the-impact-of-mowing-on-weed-pressure.
“How to Manage Pests in Gardens and Landscapes.” UC IPM Online, Mar. 2016, https://ipm.ucanr.edu/PMG/PESTNOTES/pn74113.html.
