What is Preemergent and When Should You Apply It?

• Apply TruGreen preemergent before weeds sprout for the best weed control.
• Apply preemergent when soil temperatures reach about 55°F.
• Water after application to activate the preemergent barrier.
• Spring and fall timing depends on your grass and local climate.
• TruGreen preemergent treatments are tailored to your lawn and region.

Even the healthiest lawns can fall victim to unwanted weeds. The smartest way to stop them is before they sprout, and that’s where preemergent herbicides come in.

Preemergent herbicides form the foundation of effective weed control. They target newly germinated weeds before they emerge, helping your turf stay thick, vibrant and free of invasive growth. Timing, however, makes all the difference. Applying preemergent too early or too late can limit its effectiveness, which is why understanding how and when to use it is so important.

In this guide, we’ll cover everything you need to know, including:

• What preemergent herbicides are and how they work.
• When and how to apply them for the best results.
• Common mistakes to avoid.
• Environmentally responsible and properly used options.

With TruGreen’s nationwide expertise and localized care, your lawn receives customized preemergent treatments designed for your grass type, soil and climate conditions, ensuring protection all season long. 

Think of preemergent herbicides as a shield for your lawn. When applied correctly, they create a thin barrier in the soil that stops weed seeds before they have a chance to grow. As seeds begin to sprout, their tiny shoots absorb the herbicide, which interrupts early development, so weeds never make it to the surface.

Water is key to making that barrier work. After applying a preemergent, light irrigation or rainfall helps it soak into the soil and activate. Once in place, it keeps protecting your lawn for months, or long enough to get you through an entire growing season, depending on your soil, grass type and local weather.

TruGreen specialists tailor each application to your specific lawn conditions. They look at soil composition, temperature and regional weed patterns to make sure the treatment goes down at the right time and in just the right amount. Their precise methods keep your lawn healthy while stopping weeds before they can start. 

Applying preemergent herbicide correctly makes all the difference. Each product’s success depends on even coverage, proper activation and minimal soil disturbance. Here’s a simple guide:

• Choose the right product for your grass type, weed challenges and lawn conditions.
• Mow and clear debris so the product can reach the soil surface evenly.
• Apply uniformly using a calibrated spreader or sprayer to avoid patchy coverage.
• Water lightly to activate the barrier; this is a crucial step for effectiveness.
• Avoid disturbing the soil after treatment to keep the barrier intact.
• Reapply as directed on the product label or as the barrier begins to fade.

While homeowners can apply preemergent on their own, precise timing and coverage can be tricky. TruGreen professionals handle these details for you, using advanced equipment and commercial-grade formulations to achieve consistent, season-long protection. Contact your nearest TruGreen lawn care pro, or check out our service plans here. 

Preemergent herbicides are available in granular and liquid forms, each suited to different lawn care needs.

• Granular preemergents: Ideal for large, even lawns and easy for homeowners to apply. The granules distribute evenly with a spreader and are activated by water or irrigation.
• Liquid preemergents: Provide faster absorption and precise control, making them a preferred option for professional applications or targeted areas.

TruGreen uses commercial-grade formulations engineered for uniform results across any lawn or landscape. Whether granular or liquid, these products are applied with precision to ensure consistent coverage, durability and protection for your turf. 

When it comes to weed control, homeowners often want to know more about the products used on their lawns. TruGreen follows a careful selection process to determine which products are applied. Every product we use is registered for residential use by the U.S. Environmental Protection Agency (EPA), and in many cases, our internal standards go beyond EPA requirements.

TruGreen specialists apply EPA-registered products chosen for their proven performance and suitability for the most common turf types. Each application follows detailed label directions and responsible environmental practices to help lawns stay healthy and resilient.

After a TruGreen treatment, your specialist will share instructions for watering, reentry and other follow-up care. Following these steps helps ensure the treatment works as intended and provides even, consistent results across your lawn.

Pro Tip: If you choose to apply a preemergent yourself, always read and follow the manufacturer’s directions carefully. 

Even a great product can fail if applied incorrectly. Avoid these common preemergent mistakes:

• Applying too late after the weed seed has germinated.
• Skipping the watering step needed for activation.
• Overlapping or missing areas during application.
• Disturbing the soil too soon afterward.
• Choosing the wrong herbicide for your grass type.

These errors can create uneven results and leave your lawn vulnerable to grassy weeds and broadleaf species. TruGreen’s professional technicians eliminate these challenges with precise application methods and expert timing for reliable, season-long control.

For more advice on proper lawn care, explore TruGreen’s top tips for avoiding common lawn care mistakes.