If you're wondering when to apply pre-emergent in North Texas, the answer isn’t based on the calendar—it’s based on soil temperature.
In Dallas–Fort Worth lawns, weeds begin germinating when soil temperatures consistently reach 50–55°F. Miss that window, and you’ll spend the entire summer fighting crabgrass, dandelions, and other stubborn invaders.
This is known as the 50-Degree Rule, and it’s the key to preventing weeds in St. Augustine and Bermuda grass across DFW.
Why Timing Matters for Weed Control in DFW
North Texas weather is unpredictable. We can have warm February weeks followed by cold snaps. But weeds don’t care about the month—they respond to soil warmth.
By the time you see weeds in your lawn, it’s already too late for prevention. At that point, you’re relying on post-emergent treatments, which are:
Less effective
More expensive
More stressful on your grass
The most effective weed control strategy in Dallas-Fort Worth is prevention before germination.
What Is the 50-Degree Soil Temperature Rule?
The 50-degree rule means:
When soil temperatures reach 50–55°F for several consecutive days, summer annual weeds like crabgrass begin to germinate.
In North Texas, this typically happens:
Late February to mid-March
Earlier in warmer winters
Slightly later in cooler seasons
This short window—just before germination—is when you should apply pre-emergent herbicide.
Best Pre-Emergent for St. Augustine and Bermuda Grass
Not all pre-emergent products are safe for every lawn.
St. Augustine Grass
Some herbicides that work well on Bermuda can damage St. Augustine. Always check the label to ensure it specifically lists St. Augustine as safe.
Bermuda Grass
Bermuda is generally more tolerant, but application rates still matter.
⚠️ Important: Over-application does NOT improve performance and can harm your lawn.
Always:
Read the label carefully
Follow exact coverage rates
Water lightly after application to activate
North Texas Pre-Emergent Application Timeline
Here’s a simple action plan for DFW homeowners:
Step 1: Monitor soil temperatures (Texas A&M AgriLife and local weather services often report this).
Step 2: Apply pre-emergent when soil hits 50–55°F consistently.
Step 3: Water lightly to activate the barrier.
Step 4: Consider a second application 6–8 weeks later for extended protection.
This two-step program dramatically reduces summer weed pressure.
What Happens If You Apply Pre-Emergent Too Late?
If weeds have already germinated:
Pre-emergent will not kill them
You’ll need post-emergent treatment
Control becomes more difficult
Your lawn may experience stress during summer heat
That’s why the 50-degree soil rule is so important in North Texas lawn care.
The Long-Term Weed Prevention Strategy: Thick, Healthy Sod
Even the best pre-emergent program works better on a dense lawn.
Weeds thrive in:
Thin turf
Bare patches
Compacted soil
Stressed grass
A thick, well-established lawn naturally crowds out weeds.
That’s why many DFW homeowners upgrade thin lawns with premium North Texas sod varieties like St. Augustine or Bermuda—creating a strong foundation that makes weed control easier year after year.
Can You Apply Pre-Emergent to New Sod?
In most cases, you should avoid applying pre-emergent immediately after installing new sod unless the product label specifically allows it.
New sod needs time to establish roots before chemical barriers are introduced. Always consult label instructions or a lawn professional before applying.
Frequently Asked Questions
When should I apply pre-emergent in Dallas-Fort Worth?
Typically late February to mid-March, when soil temperatures consistently reach 50–55°F.
Do I need two applications in North Texas?
Yes. A second application 6–8 weeks later extends protection through peak summer germination periods.
Is pre-emergent safe for St. Augustine grass?
Only if the label specifically states it is safe. Always verify before applying.
What is the best way to prevent weeds long-term?
A combination of proper timing, correct herbicide use, and maintaining a thick, healthy lawn.
Build a Weed-Resistant Lawn from the Ground Up
At A1 Grass, Sand & Stone, we supply premium sod varieties specifically selected for the North Texas climate. A dense, healthy lawn is your best defense against weeds—and it starts with quality turf.
If your lawn is thin, patchy, or struggling, upgrading your foundation may be the smartest long-term investment you can make.
📍 Serving Dallas–Fort Worth and surrounding North Texas communities.
📞 Contact us today to get ahead of the growing season.