Apply pre-emergence herbicides, to control annual grass weeds, two to three months prior to weed seed germination in the spring. Apply post-emergence herbicides, to kill actively growing weeds, anytime during the growing season when the air temperature is 60 to 80 degrees F.
About the Author
Jennifer Loucks has been writing since 1998. She previously worked as a technical writer for a software development company, creating software documentation, help documents and training curriculum. She now writes hobby-based articles on cooking, gardening, sewing and running. Loucks also trains for full marathons, half-marathons and shorter distance running. She holds a Bachelor of Science in animal science and business from University of Wisconsin-River Falls.