The last week or two, the evening light has lasted long enough for me to piddle around in the garden when I get home. I could not help but think, “Spring is coming!” We still have the month of February to get through, so I am trying to restrain myself. There are a few late winter tasks to start thinking about, and one of those is weed control.
If you have trouble with more weeds in your lawn than you would like, pre-emergent weed control is a good way to prevent weeds before they get a chance to grow. Pre-emergent herbicides work when weed seeds are
just beginning to germinate by stunting or deforming the tiny seedling so that it cannot emerge as a healthy weed.
Pre-emergent weed control products are good options for controlling challenging annual weeds like crabgrass or annual bluegrass. Many pre-emergent products are safe to use around established plants in the landscape, and they can reduce post-emergence herbicide applications later during the year. Prevent the weed from getting started, and you will not have to spray or physically remove it later.
The best time to apply pre-emergent products in the spring is based on soil temperatures. Apply pre-emergent products when soil temperatures reach about 55 degrees Fahrenheit for four or five days. You can use a soil thermometer, or even a meat thermometer, to measure soil temperature in the top one inch of soil in your yard.
To find the best pre-emergent product for your lawn, determine which types of weeds you need to prevent. Use the Weed Identification Guide at https://aggieturf.tamu.edu/turfgrass-weeds/ to determine if you have grassy weeds or broadleaf weeds. Most broadleaf weeds can be controlled with products that contain the active ingredient isoxaben. Grassy weeds can be controlled with products that contain pendimethalin, prodiamine, or dithiopyr. Search for those active ingredient names in small print on the bag, rather than looking for a brand name.
Follow the label on the product, making sure that you water in the pre-emergent herbicide according to the instructions. Do not rely on rain to do it for you! Chances are we will not get the rain we expected, or we will get a downpour that sends your pre-emergent herbicide running down the street.
The goal for treating weeds is to make the least number of herbicide applications. Choose the right product for your weeds, use appropriate timing based on soil temperature, and follow the label instructions. You may still have some weeds pop up this spring, but that is a good opportunity for some time outside to pull them by hand.
For more information about lawn and garden topics, contact Kate Hajda, Williamson County Horticulture Extension Agent, at 512-943-3300.
