Prior to selecting a weed killer for your lawn it is vital to understand how and why weeds grow. Weeds are like all plants in that some emerge from seeds each year (annuals) and others will come back year after year (perennials). Also, there are warm and cool season weeds, meaning that some will grow during the summer and others will only grow during the winter or when soil temperatures are lower.
Classifying Weed Types:
Just as in medicine, before you can prescribe a medicine you must first know the nature of the weed or disease. Otherwise your efforts in controlling will be in vain. There are three main types of weeds and selecting the best weed killer for lawns will come down to knowing which kind you have. They are:
Sedges are grassy weeds can be the most difficult to control. Sedges develop little balls beneath the turf that allows from them to regenerate even if you pull them. In the south (Texas) the most difficult to control grassy weed is Dallisgrass. Common broadleaf weeds include dandelions, dichondra, aster, and henbit.
How to Identify the Weed:
The website Weed Alert has a great platform for identifying your weed. You can also pull the weed and head to your local nursery or call a chemical application company and ask them what you have. Often times just knowing if you have a grassy or broadleaf weed will do the trick. You can then buy either a grassy or broadleaf weed killer. As their names indicate a grassy weed will generally look like grass and broadleaf weeds will not blend in at all with your lawn.
Pre Emergent Control vs Post Emergent
The #1 best way to control weed growth in your lawn is to apply pre-emergent weed control. As the name suggests this is a pesticide that is applied PRIOR to weed growth. Once weeds appear they are much harder to control. Pre-emergent applications should be made during the winter, spring, and fall thereby controlling weeds prior to their growth. The way they work is that they leave a “film” of weed killer on the surface of the soil so no new buds can pop through. We apply pre-m at the end of January, in March at least two weeks before weeds generally start to appear and again in the fall around September prior to winter weed growth.
One of the most common pre-emergent chemicals is Atarzine for grassy weed control. For broadleaf, simazine or benefin do a great job.
Post Emergent Weed Control
So you didn’t get any pre-emergent down and now your lawn is full of weeds. No worries . . . you can apply a post emergent weed killer for lawns and beat the infestation. Again, determine what kind of weed problem you are having; broadleaf, grassy, or sedge.
DO NOT USE ROUNDUP!
The reason we suggest not using a round up type product is that they are designed to kill EVERYTHING . . . that means that if you spray some on your lawn it will kill it, on a bush . . . dead! You can actually buy SELECTIVE HERBICIDES that are designed to not harm your grass at all and only target weeds. One option for home owners is Spectracide Weed Stop Selective Herbicide
which can be sprayed directly on the lawn. A good place to start would be to contact your local agriculture extension office. There is also a site where home owners can purchase chemicals for their lawns. DoMyOwnPestControl.com has a wide selection of pre-m and post emergent (selective) products. But be very careful! These products contain MUCH more active ingredient that anything you would buy at a big box retailer so you should exercise extreme caution. They cost much more than anything from Home Depot but when it comes to pesticides you really do get what you pay for!
Okay so you came to this page looking for the best weed killer for lawns . . . for post emergent weed control that is selective try Celsius or 3-Way or Certainty for a nut sedge problem. Again, I do not recommend that any home owner use these products without having some serious conversations with someone that has experience and knows the products. When you combine proper watering techniques with proper mowing height and consult a professional about your weed problems and fertilizer options you will be sure to achieve control of your lawn.