Crabgrass and dandelions are two of the most pernicious weeds in nearly every lawn across America. Controlling them can be difficult, especially when trying to keep the good grasses around them alive. If you have problems with both of these weeds at the same time, there are a few factors you need to consider as you select your product.
Considerations for Single Lawn Treatments
Even though crabgrass and dandelions are extremely difficult weeds to control, nearly every lawn care product manufacturer has a product that claims to deal with both quickly without killing your grass. When used correctly, these products are effective. Crabgrass and dandelions are both classified as broadleaf plants, according to Bonide, a manufacturer of one type herbicide said to treat crabgrass and dandelions simultaneously. Chemists formulate a compound that is effective on a blanket level for many various types of broadleaf plants, making for a much more efficient treatment than individual treatments targeted at specific plant varieties.
There are two key factors that will help you narrow down the product list and protect your lawn from harm in the process.
Identify the Grass to Save
When selecting any herbicide, you always want to know what varieties of grass you want to retain in the yard. Certain herbicides may be safe for use on Bermuda but not on Kentucky Bluegrass; others may work exactly opposite. Just because a chemical claims to treat crabgrass and dandelions while being safe for lawn grass doesn't mean the guarantee extends to the particular type of grass you have in your yard. You want to know before, not after, application that an herbicide is safe; otherwise your weed problem will be solved but you'll have a much more expensive "lack of grass" problem.
Know the Stage of Weeds' Growth
The second consideration according to the Ontario Ministry of Agriculture Food and Rural Affairs (OMAFRA) is at what stage the herbicide is effective on the weeds you want to kill. This will include factoring in treatment times. If you purchase an herbicide that works to contain pre-emergent crabgrass and dandelions, which germinate in spring, but want to make headway on the problem in the fall, you're going to be sorely disappointed in the results. You need to know what phase of development the weeds you want to kill are or will be in when you are ready to treat the lawn for them. Then, go to your local garden store and look for the right products. If it's spring, chances are you'll be looking for pre-emergent products. This is particularly true if you only have a spotty infestation of weeds, since this will be a minimally invasive approach. If you are treating in summer or fall, you're probably going to need an herbicide that controls mature plants.
Have Realistic Expectations
Finally, Dawn West of All About Lawns notes that the right combination of treatments should enable you to deal with both weeds successfully. Have the right expectations to avoid frustration: if half of your lawn is crabgrass and dandelions, plan on intensive treatments for a year or more. You'll need to treat for the mature plants in fall and for the pre-emergent seeds in spring. You'll also need to be spreading new grass seed to fill in the void left by the weeds; otherwise, something less desirable will likely take its place.
Once you've determined the particular variety of grass in your lawn and the stage of development the weeds will be in when you are ready to treat for them, the sea of available products will have shrunk to a manageable handful, allowing you to save money by making the right choice the first time.
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