When to Use Weed Killer: Keep Your Lawn Healthy and Beautiful

Last Updated on January 10, 2023

Unwanted weeds can make your lawn or garden appear less manicured or, in some cases, out of control. One way to get rid of unwanted weeds is with a specific weedkiller spray containing herbicides.

However, this isn’t always as easy as it seems. There are various external factors you must consider to get the full effect of the weedkiller. That’s why we compiled this handy guide on how and when to use weed killer so you can expect maximum weed killing potential every time your lawn undergoes a treatment.

Weed Killer Explained

Before anything else, let us understand first the basics of weed killers.

What Is Weed Killer?

Simply put, weedkillers kill weeds. They generally come in a spray form that you can easily apply to stunt the growth and control weeds. Weed killers typically work by attacking the roots of a weed and preventing them from growing. They can also avoid protein production on a cellular level which is also effective for killing weeds.

Some weed killers will not harm your grass and can directly target weeds. However, many are all-purpose weedkillers, like Roundup.

Glyphosate is the main ingredient of Roundup, and while it is safe for humans, it will not protect your grass or plants from the herbicide, leading to their demise as well.

Pre-Emergence Herbicides vs Post-Emergence Herbicides

The two main types of herbicide weedkillers are called pre-emergence and post-emergence.

Pre-emergence herbicides disrupt the natural life cycle of weeds to kill them. This type of weed killers is best used to kill weeds in established gardens and lawns.

Post-emergence herbicides work best when weeds and plants are still young in late Spring or early Summer.

What Is the Best Season to Use Weed Killer?

The best time of year to use weed killers on your lawn is in the early spring before the weeds get a chance to germinate. In early spring, most weeds are in a pre-growth state, and the weed killer will ideally prevent them from sprouting.

Additionally, spring is generally a wetter time of the year which helps the herbicides penetrate the soil and attack the weeds at the root.

Early Autumn is another good time to apply weed killers because they kill weeds while vulnerable before the upcoming colder months. Attacking weeds in your lawn at this time of year ensures they don’t survive the winter.

What Is the Best Time of Day to Apply Weed Killer?

The best time of day to apply a weed killer treatment is in the late morning or early afternoon. It helps prevent rapid evaporation before the weed killer can actively absorb into the dirt and start to kill the weeds.

A late afternoon treatment can also be effective, as long as it is not too hot or too cold.

What Weather Conditions are Ideal for Applying Weed Killer?

A weed killer treatment can be strongly affected by weather conditions.

For the best results, we recommend treating your garden and lawn under the following weather conditions:

• Dry weather after a rain shower when the soil is still moist. It allows the herbicide to soak into the soil faster without simply resting on top of your lawn.
• When it is not windy, so the spray doesn’t spread during application. It makes it easier to target a specific area and avoid accidentally spraying plants you wish to keep. A windy day may also cause the weedkiller to evaporate faster, which should be avoided.
• When there isn’t any rain in the forecast for at least 12-24 hours. Dry weather ensures the spray is absorbed and doesn’t become diluted or spread, possibly minimizing the results.

How Long Does it Take for Weed Killer to Work?

In general, you can expect to start seeing results within five to seven days after spraying weed killer. Depending on the specific weedkiller being used, it may take as long as two to four weeks to complete the job entirely.

How Often Should You Use Weed Killer?

Ideally, you will only have to apply weed killers seasonally. Many weed killers require an initial spray cycle followed by another two weeks later. Always read the label on your specific product as the directions vary somewhat.

Weed Killer Precautions

When spraying your lawn with a weed control spray, always make sure to keep pets and children away from the treated area for at least 24 hours. This is to ensure the proper absorption of the herbicide and all other components. You may also want to wear protective gloves and other equipment. Read the label to find out what your spray recommends.

Weed Killers and Your Garden

Now that you know how and when to use weed killer, your garden is going to look beautiful in no time! Or, at the very least, be free of weeds and full of beautiful flowers and even vegetables!

Just remember, spring is the best season to apply Roundup or any other kind of weed control spray, followed by Autumn. Also, the morning hours are the best time of day because it is neither too hot nor too cold.

Did you find this article helpful? Do you have other questions regarding weed killers? Let us know what you think in the comments below.