So how do pre- emergent herbicides stop weeds from happening in your yard? The way pre-emergent herbicide works is by putting a chemical barrier down over the top of the soil, as this does not allow the seeds to germinate above the soil line. In order to reduce the number of weeds or completely eliminate them, a pre-emergent should be applied at least twice a year. This is typically done in the beginning of the spring and fall growing seasons.
There are many different brands of pre-emergent herbicides on the market and usually come in two different delivery methods; granular and liquid. The granular depending on brand is pretty simple; apply the desired amount as per the direction labels on the bag and then water lightly to begin to dissolve the product. This type of product works very well in established flower beds and vegetable gardens. The liquid form is also a simple application process. They usually come in one of two different applications, a ready to use (RTU) and a concentrate. Concentrates must be mixed with the appropriate amount of water as listed on the instructions. While concentrates aren't ready out of the box, you usually get more bang for your buck per bottle. The RTU can be used right out of the box, just hook it up to the end of your hose nozzle and spray the application covering the yard. It’s usually color coded (typically orange, green or blue) so you can tell what has and hasn't been covered. This type of application is great on rock or desert landscapes and application time is short and very easy, just remember never to spray herbicides during windy or extremely hot days.
The last pre-emergent herbicide we'll discuss is the 2 in 1 application. This contains a weed killer and a sterilizing agent. Since you have to remove existing live weeds for the pre-emergent to work, this type offers the best of both worlds. It will kill the weeds and stop new ones from growing. Depending on your application, this can last up to a full 6 months, and is by far the best solution. Keep in mind when using the 2 in 1 type application, you don’t want to spray it on any non-weed foliage, as this may cause unwanted wilting and damage to the plants you’re trying to protect.
Moon Valley Nursery stocks all the things you will need for your weed prevention plan: