With a multitude of weed control products available, how does one choose what, how and when to use? Having a basic knowledge of how herbicides work will aid you in your quest for a weed-free lawn.
Herbicides fall into one of two categories. Pre-emergent herbicides control activity as the weed seed germinates. They inhibit this process and kill the plant as it is sprouting. Post-emergent herbicides are designed to be applied to already growing plants. Although there are exceptions, most crabgrass herbicides are pre-emergent and most broadleaf herbicides are post-emergent products.
All herbicides have a specific mode of action. There are several ways herbicides kill plants, and most of them take place on the cellular level. Inhibiting photosynthesis (food production), growing point inhibitors and cell wall disruptors are just a few examples.
Knowing how and when to apply these products is as important as choosing which product to use. The key is getting the herbicide into the target plant. Liquid products tend to produce better results, as the coverage is more even (one exception is that granular products work better than liquid when applied to wet leaves). Once the herbicide is on the leaf of the plant, it will then be absorbed and begin its process of disrupting the plant’s biology and ultimately killing the plant.
Best results are achieved when plants are actively growing, the soil has moisture, temperatures are below 80 degrees and the plant’s leaves are dry. Plants have natural defense measures that are enacted in dry and hot conditions that can impede the performance of herbicides.
Whenever you are working with pesticides, it is important to follow the manufacturer’s label. It will give you all the necessary information on how to use the product effectively.