When to Spray Lawn for Weeds: Yearly Timing

The ideal lawn is a smooth stretch of grass, so making sure there aren’t any weeds to disrupt the enjoyment of your yard is always top of the maintenance list. As all homeowners know, this is an ongoing activity that needs to be done at different times throughout the year for the best results.

Where you’re treating weed growth will define your approach. Spraying for weeds over sidewalks, driveways, and other paved areas can take a more blanket strategy than spraying weeds in your lawn or garden.

The best time of the year to spray weeds in the lawn is going to depend on when the weeds show up each spring, summer, and fall. Weeds can be hearty plants competing with your grass for soil nutrients, water, space, and sunlight, so a watchful eye and a good schedule will help you keep the grass clear of unwanted growth.

Using Herbicides

Weed-killing sprays, or herbicides, are useful products for maintaining a weed-free lawn. Since these kill plants, using them carefully is important to maintain your lawn and other greenery. Following the directions and making sure you use the right kind of herbicide for the weed you’re dealing with will ensure the best results.

A healthy lawn will be more resistant to disturbances, so keeping it watered and trimmed regularly provides a solid foundation for you to eradicate the unwanted growth.

When you target a weed, you can apply two kinds of solutions: herbicides that are pre-emergent (targeting the roots) or post-emergent (focusing on the leaves). These weed killers act efficiently and are designed for the species of weed you wish to remove, leaving the surrounding grass unharmed when the product is applied.

Since pre-emergent herbicides target the root system before leaves sprout, this kind is usually spread over the yard. When using a post-emergent herbicide product, which interacts with the weed’s leaves, it’s not a good idea to apply it across the entire lawn.

This kind should only be used on the weed plant itself, targeting the main stem and leaves for best absorption.

Using Herbicides

When Should I Treat My Lawn for Weeds?

Maintaining an annual schedule for the cycles of plant growth across the seasons is the best way to stay on top of weed control year to year.

  • End of Winter applying pre-emergent herbicide before weeds start to grow in the spring is an effective, preemptive way of managing weed growth before it happens. For weeds that grew in the winter, like many broadleaf weed species do, using post-emergent spray before your regular grass grows in will clear space for your lawn to regain its lush condition.
  • Spring – like in the cooler months at the end of winter, applying pre-emergent herbicides will help rid the yard of the roots of weeds before they sprout. Most new vegetation growth in the year will happen in spring, so targeting any unwanted growth early on will keep plants from establishing themselves and spreading in the warmer months.
  • Summer – weeds will continue to spring up throughout the year, growing alongside your lawn, trees, and garden. Respond to these as soon as you see them. If your spring treatments were effective, summertime should be spent mostly post-emergence spot treatment when you see something popping up here or there.
  • Fall – although many plants are dying or going dormant, some cool-weather-loving plants will thrive. Usually, broadleaf species of vines and forbs will continue to grow into the autumn and can be removed with post-emergent herbicide product

What Time of Day Should I Spray for Weeds?

Applying herbicides should be done in the late morning after the grass has dried from the morning dew, which can dilute the spray and make it less effective. Waiting until midday may be too late to apply weed sprays since the liquid may evaporate before it can be absorbed, especially on hot summer days.

The afternoon and evening might be too late to put herbicides on weeds since moisture collects on the leaves again as the sun sets and continues to do so into the night. The right conditions for the spray to be absorbed are the drier times of day when temperatures aren’t too high or too low.

Should You Spray Weeds Before or After Mowing?

Here again, timing is going to be about the type of herbicide you’re using on a specific kind of weed. Pre-emergent treatments should be applied after mowing since this product needs access to the soil.

A good mowing before an application will make sure the grass is trim and the ground is exposed to accept the product.

For post-emergent treatments, which interact with the leaves and stem to be absorbed throughout the plant, applying the product days before mowing will be best.

This way, the leaves of the weed are full and can absorb the most product over a period of time, while it also prevents grass that has been freshly cut from absorbing excess product through the yet unhealed blades.

Types of Weeds

Types Of Weeds

Identifying the type of unwanted plant is the first step in making sure you can root it out correctly. Some of the most common types of weeds include:

  • Broadleaf – these weeds, with round or very large leaves (as opposed to grass-like structures), are quickly noticeable in a sea of grass. Some common examples include dandelions, clover, creeping Charlie, pigweed, and thistle.
  • Tree saplings – sometimes newly sprouted saplings might be mistaken for a more pervasive weed. If these are showing up near or under a mature tree, these seedlings can be simply mowed over or pulled out, and they will stop growing.
  • Grass weeds – while you’re busy maintaining the best conditions for your lawn’s health, other grasses might grow amongst your preferred grass Crabgrass, bluegrass, and quick grass commonly show up in yards and in concrete cracks.
  • Sedge – this is another type of common weed, a grass-like plant that is thicker and has more branching stems than regular grass These also usually grow small flowers. Nutsedge, dayflower, and annual sedge are examples of these.

Author: Matt Hagens

Hi, I’m Matt the owner of Obsessed Lawn. I love to be outside working on my lawn, planning my next project. I created this website to help people like you find the best products for yard care and great advice. Learn more about me and find me on Facebook.