Dandelion control in lawns
when is the proper time to use herbicides to control dandelions in the fall of the year? Can it be done in August or should it be done in September or October?
Le Sueur County Minnesota
Unfortunately, trying to control dandelions in 2019 by doing something in 2018 may be an exercise in futility. These are perennial plants that release seeds - probably already - that germinate in early spring 2019. Destroying plants at this time of the 2018 season will have little impact upon the emergence of plants in 2019.
1). As early as possible in spring of 2019 - well before your grass starts to green up - apply a pre-emergent herbicide (e.g.,Preen) to your yard. This,hopefully,will prevent seeds released in 2018 from germinating in 2019.
2). No doubt you will still see in 2019 dandelions growing. When and if you see this, apply a broad leaf herbicide as quickly as possible.
It will not be easy to completely rid your yard of dandelions as seeds will be constantly blown in. All you can do is an holding pattern. I say this from over a 20 year battle with dandelions in my own yard, The best you can hope for is to minimize their spread. The steps that I have outlined above will bring you to this point.