How to Treat Lawn Weeds Before Winter, and Why

Originally posted on Men's Journal | By Max Winters | Last updated Oct 27, 2024 8:30 AM ET

With winter on the horizon, many homeowners often hone in on lawn care and focus on fertilizers and leaf management before the weather turns. While focusing on grass health, you should also consider the perennial weeds and how they may impact your grass's health during dormancy.

The Benefit of Removing Weeds Before Winter

Treating weeds before winter can put your grass a step ahead once the warmer weather returns. When left untreated, they'll compete with your lawn for nutrients. Lack of nutrients leads to weaker growth, thinner grass, and dead spots when the grass returns from dormancy. While we usually stop thinking about weed growth once the temperatures begin to cool off, remember that there's a wide range of common lawn weeds, and they're ready to take out your healthy lawn next year.

Additionally, some common weeds, like dandelions, thrive in cooler weather. I know that's one of the last things you want to hear, but they aren't annual weeds, and even during mild winters, common cool-season annual weeds and biennial weeds can continue to grow and spread. Removing these unwanted plants or using a selective herbicide product in the fall means your grass has a better chance to grow stronger roots, become resilient, and show off as a greener, thicker lawn in the spring.

Fall treatment interrupts the weed-growing cycle and helps many grass types. While selective broadleaf herbicides aren't always considered for fall use, they can still help prevent pesky weeds when your grass is dormant. Pre-winter weed control will help you avoid a larger problem in the spring, making lawn maintenance easier and less labor-intensive.

Best Practices for Pre-Winter Weed Control

Choose the right timing. Aim for early fall if possible, as weeds are still growing and actively absorbing nutrients. This improves the effectiveness of any doses of herbicide applied to the grass.
Select your herbicide. Opt for a product specifically designed for broadleaf weeds, which are common in residential lawns. Broadleaf lawn weeds respond best to active ingredients that target how the family of weeds grows within lawn grasses.
Avoid treating new lawns. Do not apply chemical herbicides on newly seeded or overseeded lawns, as it can harm immature grass seed.
Remove large weeds manually. Pull out the entire weed clump by hand to prevent it from seed pods and spreading further. If you don't get all of it, apply a treatment that will get down to any remaining deep roots.
Adjust your mowing height. Mow your lawn slightly shorter than usual in the fall to help limit weed growth. It won't affect the grass roots of your dormant lawn.
Rake regularly. Clear fallen leaves to prevent damp, shaded conditions that encourage propagation.

How Weeds Affect Grass Health During Dormancy

When lawns go dormant in winter, grass growth slows down significantly. However, some weeds can continue to grow and thrive even in colder weather, which puts stress on your grass. Those that survive the winter can overshadow dormant grass, blocking sunlight and reducing available nutrients once growth resumes in the spring. The result? A lawn that’s more sparse and less resilient, with weeds firmly rooted and ready to spread as the spring temperatures rise.

Pre-winter weed control is especially beneficial for homeowners who have experienced problems in the past. A proactive approach reduces the likelihood that they'll become established in bare patches and helps your lawn emerges from winter ready to flourish.

FAQ

How can I prevent weeds from returning in the spring?

Applying a pre-emergent herbicide in early spring can help prevent them from sprouting. Keeping your lawn healthy by regularly mowing, watering, and fertilizing in the fall will also make it harder for weeds to establish in the spring, as thicker grass naturally crowds out and minimizes the growth of winter weeds.

Does soil temperature affect the effectiveness of weed control products?

Yes, soil temperature plays a significant role in the effectiveness of weed control products. Most herbicides work best when soil temperatures are between 55°F and 75°F, as weeds are actively growing and absorbing nutrients in this range. If the soil is too cold, they'll go dormant and won’t absorb the herbicide as effectively, which can reduce the treatment's success. Monitoring soil temperature in early fall can help you time applications for optimal results.

This article first appeared on Men's Journal and was syndicated with permission.

More must-reads: