As the sweltering Houston summer begins to fade, it’s time to shift your lawn care strategy from survival mode to preparation with fall pre-emergent. The cooler weather of fall is a welcome relief, but it also marks the beginning of a new threat to your pristine lawn: winter weeds. If you’ve ever battled with stubborn invaders like Poa annua, henbit, or even dallisgrass, you know how frustrating they can be. The secret to a weed-free lawn next spring isn’t a miracle cure—it’s a proactive defense. And that defense starts with a fall pre-emergent.
What’s a Pre-Emergent and Why Does It Matter for Fall?
Think of a pre-emergent herbicide as a shield for your lawn. Unlike a post-emergent, which kills weeds that have already sprouted, a pre-emergent works by forming a protective barrier in the soil. This barrier precludes weed seeds from germinating and taking root. It’s the ultimate “prevention is better than cure” strategy.
So, do weeds die in the winter? Unfortunately, many of the most persistent weeds in our region thrive in the cooler weather. They germinate in the fall and grow through the winter, ready to take over your lawn in the spring. By applying a fall pre-emergent, you’re stopping these weeds before they even have a chance to get started.
The Usual Suspects: Weeds to Watch Out For
Here in Houston, several common winter weeds can wreak havoc on your turf. Applying a pre-emergent in the fall is your best defense against:
- Poa annua (Annual Bluegrass): This is one of the most common and frustrating winter weeds. It’s a light green grass that forms dense clumps and produces unsightly seed heads.
- Henbit: A broadleaf weed with square stems and small purple flowers that can quickly spread and cover large areas.
- Burweed (Sticker Weed): This sneaky weed is a major nuisance. It germinates in the fall and creates sharp, spiky burrs in the spring that are painful to step on.
- Dallisgrass & Crabgrass: While often considered summer weeds, these can also be prevented with the right pre-emergent timing. A well-timed fall application can help reduce their presence next year.
When and How to Apply Your Fall Pre-Emergent
Timing is everything when it comes to lawn maintenance for fall. The ideal time to apply a pre-emergent in the Houston area is generally from mid-September through October, when soil temperatures consistently drop below 70 degrees Fahrenheit. If you wait too long, the weed seeds may have already germinated, rendering the pre-emergent ineffective.
Tips for a successful application:
- Check the label: Always read the instructions on your pre-emergent herbicide product. The application rates and instructions can vary by brand and lawn type.
- Mow first: Mow your lawn to its normal height before application.
- Water it in: After applying the granules or spray, you must water your lawn thoroughly. This activates the product and helps it form that essential barrier in the soil.
- Aerate if needed: If you plan to aerate your lawn, do it before applying the pre-emergent, as breaking the soil barrier after application will compromise its effectiveness.
The Verdict: Pre-Emergent vs. Post-Emergent
While post-emergents have their place for spot-treating a few stray weeds, they are not a substitute for a good pre-emergent strategy. Trying to kill a yard full of winter weeds in the spring is a much more difficult and costly battle. A fall pre-emergent is the most effective and efficient way to prevent weeds from growing and ensure your lawn looks its best.
This fall, don’t just admire the cooler weather—take action. Invest in a quality pre-emergent and give your lawn the head start it needs for a beautiful, weed-free spring. Your future self (and your bare feet) will thank you.
Featured Image Source: A&M Agrilife