How do Weed Killers Work?

Weeds are every homeowner’s nightmare. They’re invasive, unsightly, and notoriously hard to get rid of. Whether you’ve just noticed a small patch marring your otherwise-lush lawn or you’ve been waging a battle against grass weeds for years, you may be considering purchasing a weed killer.

It’s important to remember that there are four main types of weed killer, each designed for a specific purpose.


Emergence weed killer is designed to prevent weeds before they ever have the opportunity to germinate. These products are a great choice for homeowners who see the same weed issues year after year but they don’t work well once weeds have been spotted.


Persistence herbicides are some of the more powerful weed killing products on the market. They’re designed to release active ingredients slowly over time and can be detrimental to anything growing where they’re applied, not just weeds. While persistence weed killer can be helpful for hard-to-eradicate weed problems, application must be timed perfectly in order to avoid killing your grass.


Selective weed killers are the most common type of commercial weed killer sold. They’re designed for use in an area where plants other than weeds are desired such as flower beds or in grassy lawns. These herbicides selectively kill the weeds in question and won’t hurt neighboring plants – but their lack of power can make them less effective against tough weeds.


Contact weed killer is designed to literally kill weeds on contact, much like powerful insecticides work. The problem with these products is that they can harm neighboring plants and sometimes don’t keep the weed gone for long. In contrast, translocation weed killer allows the weed to absorb the poison over time as it leeches through its root system, but can take a while to show effectiveness.

How to Apply Weed Killer to Your Yard

Each and every weed killer you buy will include very specific instructions on its use and application. It’s always important to follow these guidelines to the letter to avoid scorching your lawn and also for your own personal safety.

A few things to keep in mind when applying weed killer:

  • Avoid mowing the lawn for a few days before and after weed killer application
  • Don’t allow kids or pets on the lawn for at least 48-hours after application
  • It’s best to apply weed killer late in the fall. If that cannot be accomplished, early spring will work.
  • Always wear gloves and use a safety mask when applying herbicide to your yard

In general, there are a few different types of weed killer.

GRANUAL herbicides come packages like dirt in bags and appear as small, hard granules. Great caution should be used with granules to sufficiently dilute the herbicide and all contact with skin should be avoided.

LIQUID herbicides are typically applied with a  hand or hose sprayer and different brands need to be diluted differently. Never get liquid spray into your eyes or directly on skin.

If you’re still unsure about the best way to handle your yard’s weed issues contact a professional to discuss weed killer options. A professional lawn care provider can safety, effectively set you up with a weed plan that will leave your yard lush and healthy for less than you think.

TruGreen will gladly visit your property as often as needed between scheduled visits to make any necessary adjustments and to ensure your satisfaction.

Getting Started with TruGreen

  1. Call or fill out the form above to reach a lawn care specialist.
  2. Know the square footage of your yard, as well as any specific areas of concern.
  3. With the help of your specialist, create a customized lawn care plan that meets your lawn’s needs.
  4. Schedule your Healthy Lawn Analysis2 to start your service.