Split Pre-Emergent Applications: Why Two Passes Beat One in Arlington

When it comes to pre-emergent herbicides, most homeowners think of a single application as the standard approach. Put it down in early spring, move on with your life. But the most effective weed control programs — particularly for North Texas lawns where crabgrass pressure is intense — use a split application strategy: two passes at a lower rate each, spaced four to six weeks apart, rather than one heavy application. Our weed control and fertilizer program uses split applications to maximize season-long protection in Arlington and surrounding DFW communities.

What a Split Application Is

A split application means dividing your total pre-emergent rate into two applications rather than applying the full label rate all at once. For example, instead of applying 0.37 lb of prodiamine per 1,000 sq ft in a single pass, you might apply 0.18 lb in late February and another 0.18 lb in early to mid-April. The total product used is similar; the distribution over time is what changes — and that difference dramatically improves full-season weed control.

• Pass one: Early in the window (late February to early March in Arlington), targeting the first flush of crabgrass germination.
• Pass two: Four to six weeks later (early to mid-April), extending the barrier into late spring when a second germination wave typically occurs.
• Total rate: Stays within label limits — you’re splitting the allowable rate, not doubling it.

Why a Single Heavy Application Falls Short

A single full-rate application puts maximum product in the ground early in the season. This sounds thorough, but it has a built-in weakness: pre-emergent barrier strength peaks at application and then steadily declines over time as the active ingredient degrades from heat, UV exposure, microbial activity, and irrigation. By late April and May — when crabgrass germination pressure in North Texas is actually at its highest — that early-season barrier may be significantly depleted.

The result is a lawn that’s well protected in early spring when weed pressure is still building, but increasingly vulnerable exactly when you need protection most. A single early application is also more susceptible to failure if activation rains are delayed or if a dry stretch in late spring reduces the product’s effectiveness.

How Split Applications Extend the Window

The split approach keeps fresh, fully potent barrier in the soil throughout the entire germination season rather than front-loading all your protection at the beginning. Here’s how it works in practice for Arlington-area lawns:

• The first pass creates the initial barrier, stopping early-germinating seeds as soil temps cross 50°F in late February and March.
• As that first application begins to decline through April, the second pass replenishes the barrier before the major spring crabgrass flush in May.
• The result is consistent, high-level protection through the entire germination season rather than strong protection early and weak protection late.
• The second application also provides redundancy if the first pass had any activation issues due to dry conditions.

Research Behind the Split Strategy

Turfgrass research from Texas A&M and other university extension programs has consistently shown that split pre-emergent applications outperform single applications for season-long crabgrass control. Studies comparing single vs. split applications of prodiamine on bermudagrass lawns — the dominant turf type across Arlington — found significantly lower crabgrass populations at the end of the season in split-application plots, even when total product amounts were equivalent. The extended barrier window, particularly into May, accounts for most of that difference.

Does Split Application Cost More?

Not necessarily. Because the total product applied per season is similar, material costs are roughly the same. The cost is primarily in the second service visit. For homeowners doing their own applications, that’s an extra hour of work and one more trip to the store. For customers on our program, the split strategy is built into the service schedule with no extra complexity on your end. The cost of a second application is almost always less than the cost of trying to control crabgrass post-emergent after a single-application failure — particularly when you factor in product costs and multiple follow-up treatments that mature weed populations often require.

What Weeds Split Applications Target

The split strategy is most valuable for crabgrass and other summer annual grasses that have an extended germination window in North Texas. Crabgrass doesn’t germinate all at once — it germinates over a period of weeks to months as soil conditions vary, which is exactly why a sustained barrier is so much more effective than a single early pulse. Goosegrass, spurge, and some annual broadleaf weeds also benefit from extended barrier coverage.

• Crabgrass: Primary target — germinates from March through June in DFW.
• Goosegrass: Typically germinates two to four weeks after crabgrass, making it a perfect target for the second pass.
• Spurge: Summer annual broadleaf that also benefits from extended barrier coverage into May.

Spring vs. Fall: Does Splitting Work for Both?

Yes, though fall split applications are less commonly used because winter annual weed germination tends to be more concentrated in a shorter window than summer annuals. A fall split can still add value for high-pressure Poa annua situations, but most programs focus the split strategy on the spring application where the extended germination window makes two passes most beneficial.