Do you gaze out your window each summer and just want to pull your hair out there are so many weeds? Why does your neighbor’s yard look so weed free, when you never see him out there pulling and pulling and pulling. Stop suffering from yard envy and do what the pro’s do. Put out PRE EMERGENT HERBICIDES (Pre-M). What exactly is this wonder of a substance? Pre-M is a class of chemicals that you spread/spray in the spring and fall that prevents germinating seeds from growing. Mind you this means just about all seeds, including those that you actually wanted to germinate (more about that later). They work by forming a chemical barrier in the top 1” of soil where most seeds lay in wait until optimal growing conditions rise allowing them to pop open and begin to grow. They don’t prevent the seeds themselves from germinating, but interrupt the process before a sprout has the opportunity to push through the soil.
Are you ready to jump on board the PRE-M train?
Well, first off, timing is critical for Pre-M to be effective. As the chemical barrier begins to break down after six to eight weeks, you do not want to apply it too early, else you lose effectiveness. But applying it too late can mean you missed out as well. Tricky, Tricky, Tricky, I know, but you need to actually read the weather cues to hit the mark. Additionally, if you plan to plant any new plants from seed (i.e. seeding a Fescue Lawn or direct sowing perennials), you must skip the PRE-M step and deal with pesky weeds after the new plants are established. Oh and by the way, as with any chemical, make sure you follow the label instructions when handling and applying the product.
Why do I still have weeds?
So, you put out your PRE-M, but you still have weeds showing up, what gives? Well several factors could affect the application. The first obvious cause for failure is that your weeds did not germinate from seeds but were perennial weeds that rose from existing root stock. Pre-m only works on seeds. If this was not the case, did you put your PRE-M out too early, or too late? Maybe you never watered it in. The easiest way is to apply it right before a rainstorm or you can use your irrigation system to water the area down. One other cause might be that the soil layer was disturb somehow breaking down that chemical barrier. Lastly, I hope you weren’t trying to save a few pennies and did not put it out at the appropriate rate listed. READ THE PRODUCT LABEL.
In all, one chemical is not foolproof, but with good attention to detail, you can greatly reduce your weed population and get the landscape that you love.