If you’ve ever watched crabgrass creep across your Texas lawn by May and wondered what went wrong, the answer almost always comes down to one thing: timing. Pre-emergent herbicide is the single most effective tool Texas homeowners have against spring and summer weeds—but it only works if you put it down before weed seeds germinate. Miss that window, and you’re playing catch-up all season long.
Let’s walk through exactly when to apply pre-emergent in Texas, how to read the signals your lawn is giving you, and what to do if you’re worried you’re already late.
What Pre-Emergent Actually Does
Before we talk timing, it helps to understand the mechanism. Pre-emergent herbicides create a chemical barrier in the top layer of soil. When weed seeds begin to germinate and push out their first tiny roots, the herbicide disrupts cell division and kills the seedling before it ever breaks the surface.
Here’s the critical point: pre-emergent does not kill existing weeds. It only prevents new ones from establishing. If you can already see crabgrass or other weeds growing, you’ve missed the pre-emergent window for those plants, and you’ll need a post-emergent strategy instead.
This is why timing matters so much. You need the barrier in place before germination begins.
The Soil Temperature Rule
Forget calendar dates. Texas is enormous—what works in the Rio Grande Valley won’t match the timing for the Panhandle. Instead, focus on soil temperature, which is the actual trigger for weed seed germination.
The magic number: 55°F at a 4-inch depth for 3-5 consecutive days.
When soil temperatures consistently hit 55°F, crabgrass and other warm-season annual weeds begin germinating. You want your pre-emergent applied and watered in before this threshold is reached—ideally when soil temps are in the high 40s to low 50s.
How to Check Soil Temperature
You don’t need fancy equipment. A simple soil thermometer (about $10 at any garden center or hardware store) works perfectly. Push it 4 inches into bare soil in a sunny area of your lawn and check it in the morning for several days in a row.
You can also check the Greencast soil temperature map for a general read on your area, though nothing beats measuring your own yard.
Typical Timing by Texas Region
While soil temperature is your primary guide, here are the general windows most Texas homeowners can expect:
- South Texas (San Antonio, Houston, Corpus Christi): Late January to mid-February. These areas warm up fast, and it’s not unusual for soil temps to hit 55°F by early February.
- Central Texas (Austin, Waco, Dallas-Fort Worth): Mid-February to early March. The DFW metroplex typically sees the window open in the last two weeks of February.
- North Texas and Panhandle (Amarillo, Lubbock): Late February to mid-March. Higher elevations and colder winters push the window later.
If you’re reading this in mid-to-late February 2026, most of Texas is right in the sweet spot. South Texas homeowners should have already applied or should do so this week. Central Texas folks—this is your moment. North Texas, you’ve got a couple more weeks, but don’t wait too long.
Choosing the Right Product
The two most common pre-emergent active ingredients for Texas lawns are:
Prodiamine (Barricade)
- Longest-lasting residual control (up to 6 months)
- Excellent on crabgrass, goosegrass, and Poa annua
- Available as granular or liquid
- Safe for Bermuda, St. Augustine, Zoysia, and Buffalo grass
Dithiopyr (Dimension)
- Provides some early post-emergent activity on crabgrass (can kill very young seedlings)
- Good residual, though slightly shorter than prodiamine
- Solid choice if you think you might be slightly late
For most Texas homeowners, prodiamine is the go-to because of its long residual. If you’re worried about timing and want a little insurance, dithiopyr gives you a small grace period since it can knock out freshly germinated crabgrass seedlings.
Application Rates
Follow the label—always. But as a general guideline for granular prodiamine on established Texas lawns, you’re looking at roughly 1.5 pounds of product per 1,000 square feet (the exact rate depends on the concentration of your specific product). Spread it evenly with a broadcast spreader for the most consistent coverage.
The Watering Step You Can’t Skip
This is where many homeowners stumble. Pre-emergent herbicide sits on top of the grass blades and soil surface after application. It must be watered in with at least 0.5 inches of irrigation or rain within 24-48 hours to move the chemical into the soil where it forms that protective barrier.
No water = no barrier = no weed prevention. Period.
If rain is in the forecast, you can time your application to let nature do the work. Otherwise, run your irrigation system for about 20-30 minutes per zone (depending on your sprinkler output) after applying.
The Split Application Strategy
Here’s a pro tip that many lawn care professionals in Texas swear by: instead of putting down the full rate in one application, split it into two half-rate applications about 8-10 weeks apart.
For example:
- First application: Mid-February at half the label rate
- Second application: Late April at half the label rate
This extends your weed prevention coverage deep into summer, catching late-germinating weeds like crabgrass and goosegrass that a single application might not suppress through the entire warm season. If you’ve struggled with summer weeds breaking through in June or July, the split application approach is worth trying.
What If You’re Late?
Don’t panic. If soil temperatures have already crossed 55°F and you haven’t applied yet, you still have options:
- Apply immediately anyway. Pre-emergent will still prevent seeds that haven’t germinated yet, and there are always late germinators.
- Use dithiopyr (Dimension) instead of prodiamine—it offers some early post-emergent control on very young crabgrass.
- Plan for a post-emergent backup. If weeds do break through, products containing quinclorac can target crabgrass in established warm-season lawns.
Being a week or two late isn’t a disaster. Being a month late means you’ll likely need a combination approach.
Common Mistakes to Avoid
Applying to bare soil where you plan to seed. Pre-emergent doesn’t distinguish between weed seeds and grass seeds. If you’re planning to overseed or establish new turf this spring, skip the pre-emergent in those areas, or wait at least 60-90 days after application before seeding.
Aerating after application. Core aeration punches holes through the pre-emergent barrier, reducing its effectiveness. Always aerate before applying pre-emergent, not after. If you need to aerate this spring, check out our guide on pre-spring lawn preparation in Texas for tips on sequencing your tasks.
Skipping the fall application. Many Texas homeowners only think about pre-emergent in spring, but a fall application (typically September-October) targets winter annuals like Poa annua and henbit. For a complete annual weed management strategy, two rounds per year is ideal. Our post on transitioning from summer to fall lawn care in Texas covers the fall timing.
Fitting Pre-Emergent Into Your Spring Routine
Pre-emergent is just one piece of the spring puzzle. Here’s a rough sequence for Texas lawns in February and March:
- Soil test (if you haven’t in the past year)
- Apply pre-emergent (once soil temps approach 55°F)
- Water in the application
- Wait 2-3 weeks, then begin your first fertilization when the lawn starts actively greening up
- Begin regular mowing once growth resumes
For a deeper dive into the full spring preparation process, our guide on early spring lawn care in Texas walks through soil testing, fertilization timing, and mowing strategy.
The Bottom Line
Pre-emergent herbicide is the most impactful thing you can do for your Texas lawn in February. The timing window is short, and once it closes, you can’t get it back. Check your soil temperature, choose a quality product (prodiamine or dithiopyr), apply evenly, water it in, and consider splitting the application for season-long coverage.
Your future self—the one relaxing on a thick, weed-free lawn in June—will thank you.
Want the complete, season-by-season guide to Texas lawn care? Lush Lawns: Texas covers everything from soil prep to summer survival, written specifically for the unique challenges of growing grass in the Lone Star State.