A vigorous, healthy turf is the best defense against weeds but getting that thick, weed-free lawn can be a process. If your lawn already has weeds or the turf is patchy and thinning the grass won’t have a chance to choke the weeds out, enabling them to compete for nutrients and spread even further. To resolve weed issues, you have two options: remove weeds and their root system by hand or remove weeds chemically by applying an herbicide.
There are two main types of herbicides, pre-emergents and post-emergents. Pre-Emergent weed controls, like Barricade® and Dimension Plus Lawn Food, are intended to prevent weeds and will not eliminate weeds that have already had a chance to germinate and grow above the turf canopy. Pre-emergent products tend to be particularly effective in controlling grassy weeds like crab grass, goosegrass, poa annua, fox tail and barnyard grass. Remember, in the same way that pre-emergent weed controls prevent germination of weeds, they can also inhibit the germination of turf. If you plan to do any seeding, you’ll want to refer to your product’s label for proper timing.
Post-emergent weed controls won’t provide the season-long weed prevention of a pre-emergent, but they will kill any existing weeds. They must be applied when the weeds are actively growing and temperatures are mild. Post-emergent products, like Surge® Weed and Feed and Weed and Feed, are effective in controlling broadleaf weeds like dandelion, clover, chickweed, henbit and oxalis.
Once you have your weed situation resolved, proper fertilization, mowing, and watering will be the key to keeping a dense, weed-free lawn.