When to Apply Weed Killer to Your Lawn

Are you noticing weeds growing on your lawn? You could pull weeds by hand, a safe and effective option. Or go straight to a weed killer to eliminate these unwanted plants. Weedkillers, or herbicides, are made from chemicals that can be harmful to people, wildlife and the environment. Before you begin using herbicides, you need to consider several factors, including preferred time of year. Ultimately, timing is everything, so knowing when to apply weed killer to a lawn is important.

We spoke to two lawn experts about when to apply weed killer to the lawn, what alternatives there are to using a herbicide, and why following lawn care best practices, including proper mowing and watering, is the best way to prevent weeds from sprouting to prevent in advance.

When should weed killers be used?

Applying weed killers to your lawn should be done at a specific time of year. The type of weed – annual or perennial – serves as a guide to when action should be taken. “By identifying the weeds, you can determine the timing of weed removal prior to flowering and seed production,” says Teresa Watkins, host of the iHeart garden radio show “Better Lawns and Gardens” on WFLA-Orlando, landscape architect/owner of Sustainable Horticultural Environments.

For perennial weeds, it is best to apply a weed killer when the weather begins to cool after the intensity of summer. “If you want to use a control product, whether organic or chemical, fall is the best time of year to control perennial weeds,” says John Cannon, franchise owner of NaturaLawn of America, Charlotte, North Carolina. The reason lies in how plants absorb nutrients at this time of year and thus increase the effect. “In the fall, plants that are dormant pull nutrients into their root system rather than pushing them into the leaves, so any control products get to the root zone more quickly this time of year,” says Cannon.

If you have annual weeds, spring is the best time to control them, he says.

Why you should reconsider weed killers

Herbicides are made up of powerful chemicals that can be harmful to people, animals, insects and the environment. “Some of the most common are glyphosate-based herbicides like Round-Up, as well as products containing 2,4-D, which has been linked to cancer in dogs and non-Hodgkin lymphoma in children,” says Cannon.

Not only do they contain toxic ingredients, but herbicides must be used frequently and not as a one-time solution. “These chemical control measures will never be a long-term solution to a weed problem and they create other environmental problems by contaminating our groundwater, lakes and streams,” says Cannon. Once you start using herbicides, it's a never-ending cycle of spending money on products and spending time applying them to your lawn, especially when weeds can be controlled in a better, easier, and healthier way. Chemical weed killers can also lose their effectiveness in destroying weeds. So instead of finding a solution for fewer weeds, it could create more problems that need to be addressed. “Over time, the weeds in your lawn may even develop resistance or immunity to pesticides if overused,” he says.

Chemicals leach into the soil and affect your lawn and garden. Healthy soil contains microorganisms and fungi that help plants grow and thrive. However, the use of herbicides has the opposite effect. “Pesticides can also harm the beneficial organisms in the soil that we call the “good organisms.” [that] “help naturally reduce other unwanted problems like lawn diseases,” says Cannon. A small problem – clearing weeds – can become a larger problem that can impact your landscape. According to Watkins, “Overuse or incorrect use of a chemical product will lead to further problems in the landscape.”

Before choosing a chemical weed killer, consider alternatives that are less harmful to the environment, the garden, the lawn and your wallet. Better yet, take the time to care for your lawn and fewer weeds will germinate in the first place.

Why caring for a lawn prevents weeds

The best way to prevent weeds is to maintain your lawn so that weeds don't have a chance to grow. “Understanding how to prevent weeds with proper care is more efficient than trying to get rid of weeds with chemicals,” says Watkins. “If the lawn is cared for properly, weeds are less likely to take hold.”

Prevention saves you money on purchasing unnecessary products as well as the time and effort required to use them. “If you plan to control weeds by spraying pesticides, you will be doing this for the rest of your life,” Cannon says. To minimize weed germination, grow a lawn where weeds cannot compete for the same resources. Weeds are simply an “out of place plant” that require the same resources to grow – sunlight, water, soil and air circulation. “To truly control weeds, you need to suppress them with a thick, healthy lawn that you can encourage through proper watering and mowing practices,” says Cannon. “Weed control is all about competition, because a healthy and properly maintained lawn makes it much harder for these pesky weeds to take hold,” he says.

mowing

The type of lawn will indicate how much grass you need to cut each time you mow. Cutting too much or too little can damage the grass and make it more vulnerable. Two easy ways to ensure the grass is mowed properly, Cannon says, are to know the type of lawn and the amount to be mowed, and to use a sharp mower blade to avoid cracks or cracks, which are essentially open ones wounds on the plant. If leaf blades are not trimmed properly, the lawn will be weakened.

irrigation

Watering too frequently can affect the root system and encourage weeds. Some weeds have shallow root systems. Watering a lawn frequently can encourage weed growth and also affect the growth of your grass roots. “Many annual weeds have very shallow root systems, so frequent or shallow watering not only keeps moisture where the weed roots are, but also promotes a shallow root system for your lawn grass,” says Cannon. Lawns with a shallow root system can cause dieback in hot weather. “If you have a shallow root system, the lawn will die from drought stress, even if you water daily,” he says. “This becomes a bigger problem, especially in the south, as summer comes.”

Knowing how much water the lawn needs and how often can help prevent the grass from becoming a perfect haven for weeds. “Proper watering ensures a healthy root system, which helps maintain the lawn,” says Watkins.

Check for weeds

Prevention is key. The easiest way to get rid of weeds is before they begin to germinate and become established. Check the lawn and look for unwanted plants sharing space in the grass. “A weekly walk through your garden will help identify weeds before they take over and a stronger herbicide is in order,” says Watkins. Mowing the weeds can prevent them from spreading. “If weeds are growing, mow them before they develop flowers and sow them,” she adds.

Tips for applying weedkiller

If you decide to use a weed killer, follow these guidelines and tips.

Avoid windy days

Choose a day without wind to apply a weed killer. “Avoid applying herbicides on windy days to minimize drift on other plants, pets or people,” Cannon says.

Read the label

Whether you use a chemical-based herbicide or a nontoxic option, read the label to learn exactly how to apply it and protect yourself. “This label lists all safety precautions and PPE (personal protective equipment) that must be worn when working with the product,” says Cannon. These are strong chemical products that can have negative effects if used improperly. “Failure to follow labeled instructions can result in long-term serious illness or even death to humans and animals, as well as permanent environmental damage,” says Cannon.

Avoid the area

The label may state that you must wear protective equipment when handling and applying the product. This is a good indicator that the product is harmful. After application, avoid the area until it is dry and there is less risk of exposure. “Keep pets and children away from treated areas until the product has completely dried or settled,” says Cannon.