Pre-Emergent Weed Control in Turf and Landscape

Spring is the time whent urf and landscape pre-emergent applications are performed.  

By applying a pre-emergent herbicide into lawns, landscape beds, or bare ground areas you prevent many unsightly weeds from germinating and virtually eliminate many long, labor intensive hours of spraying or digging weeds after they've established.

In turf, we apply pre-emergent herbicides to control crabgrass. Barricade and Dimension are the two industry standards for crabgrass pre-emergent control. Both products at highest labeled rates will give anywhere from 4-6 months of control, depending on certain conditions. Crabgrass germinates when soil temperatures have reached 60 degrees for a straight week at a 2" depth. With this in mind, one must monitor temperatures to get their pre-emergents in place before the 60 degree mark is reached. Here in Southern Idaho, that time could be anywhere from late March through early May, depending on the year. Dimension also has the ability to kill already germinated crabgrass up to the two leaf stage. So if the window has been missed to apply a product before the 60 degree mark, one could still apply Dimension and kill off any existing immature crabgrass and prevent any other crabgrass seeds from germinating. Both products also control a number of other broadleaf and grassy weeds as well. Both Barricade and Dimension come in both sprayable and granular forms, the granular Barricade being a Fertilizer + Barricade.

In landscape beds, weed invasion is a major problem that homeowners and landscape maintenance crews have to deal with throughout the year. Once again, pre-emergent herbicides can help to eliminate many hours spent weeding or spot spraying these beds to kill off existing weeds. Weeds are considerably more prominent in bedding areas than in turf due to the lack of competition and also higher surface temperatures due to direct exposure from sunlight. Usually in landscape beds, two pre-emergent applications, once in March-April and again in Sept-Oct., will give control throughout the entire year. There are a number of different granular and sprayable products to choose from depending on the application. Maturity of the landscape beds, types of plant materials, existing weed fabric, types of covering (rock, bark, mulch), surrounding turf, are all things to consider when determining what products to use in these beds. Some different granular products labeled for landscape beds are: Barricade, Dimension, Snapshot, Freehand, Treflan and Casoron. Some different sprayable products include: Barricade, Dimension, Gallery, Sureguard, Surflan, and Pendimethalin. All pre-emergent products will need to be watered in within a few weeks either by rain or sprinkler irrigation to form its barrier. As with any chemical, always read the label to determine specific rates, concerns with existing vegetation, and general safety precautions and consult with a licensed dealer on any other questions or concerns.

Costs of pre-emergents are definitely a concern when it comes to bidding jobs in today's tough economy. Some people consider these applications as easy ones to eliminate when cutting costs. It doesn't take a long time to regret a decision like this. It has been proven time and time, again, that pre-emergent herbicides will save money in both labor and materials over a year's time. Check with your local sales representative to determine what product might work best in your situation this year.

Pat Sherer

Simplot Partners - Caldwell, ID