Why Smart Denver Homeowners Tackle Weeds With a Real Program (And Why Spring Timing Matters)

The Best Weed Control Strategy Isn't One Treatment. It's a Program.

We get this question all the time from Denver homeowners: "Why does my lawn keep getting weeds even though I treat them?"

The answer is almost always the same. They're fighting weeds reactively, one battle at a time, instead of running a real program.

A real weed control program uses two types of treatment doing two distinct jobs, applied on a schedule across the whole season. Most people do one treatment and call it done, which is why the weeds keep coming back.

We're excited to share that we now offer both treatments as part of our service lineup at ACA. We've had this on the request list from clients for years, and we're finally able to deliver it the right way, with the right products, at the right times.

Here's what each one does and why a complete program uses both.

Pre-Emergent: Stop Weeds Before They Start

Pre-emergent weed control is the most underrated treatment in lawn care. It doesn't kill weeds. It prevents them from ever existing in the first place.

Here's how it works. When we apply pre-emergent prior to annual weeds germinating, the product creates a protective barrier in the top layer of your soil. Weed seeds (especially crabgrass and other annual weeds) try to germinate when soil temperatures warm up. They hit that barrier and never sprout.

The trade-off is that timing is everything. Pre-emergent has to be in the soil before weed seeds wake up. Once annual weeds and crabgrass germinate, it's too late for pre-emergent that season. You're in reactive mode.

This is why we book pre-emergent customers early. The window is short, it fills up fast, and missing it costs you the whole growing season.

Pre-emergent is right for you if:

• You want to prevent crabgrass and other annual weeds from germinating
• Your lawn had weed pressure last year and you don't want a repeat
• You're not planning to overseed this spring (pre-emergent blocks all seed germination, including grass seed)

What to know:

• It does NOT kill existing weeds. It only prevents new ones.
• Water anytime after the application, even right away. Watering is actually a good thing here, since water is what activates the product and carries it down into the soil where the barrier forms.
• Hold off on mowing for 24 hours after the application so the soil and the barrier aren't disturbed.
• A complete program includes a second pre-emergent application in the fall, before winter weeds germinate, to keep next spring's crop from getting started. Skip the fall round if you plan to overseed, since pre-emergent blocks grass seed too.

Post-Emergent: Eliminate Weeds That Are Already There

Post-emergent is what most people think of when they hear "weed control." It's the treatment that targets and kills the weeds you can already see growing in your lawn. Dandelions, clover, thistle, and other broadleaf weeds.

Here's the part most homeowners miss. Post-emergent isn't just about killing what's there. It's about creating conditions where healthy grass crowds weeds out over time.

We use professional-grade products applied at the right point in the growing season. The weeds have to be actively growing for the treatment to work, which means spring through early fall is the right window. Results are typically visible within 7 to 14 days.

And the question every homeowner asks first. Yes, your kids and pets can use the lawn again the same day in most cases. Just keep them off until the product has completely dried, which usually takes 2 to 4 hours depending on temperature, humidity, and sunlight. For maximum safety and full absorption, we recommend waiting 24 to 48 hours.

A few things to know about post-emergent treatment:

• A complete program uses several post-emergent treatments through the season, spaced about 30 to 60 days apart, so new weeds get caught as they appear instead of taking over between visits.
• Avoid mowing for 24 hours before the treatment, since the product is absorbed through the weeds' leaves and cutting them down leaves too little leaf surface for it to work. Then avoid mowing for 24 hours after so the product has time to absorb.
• Avoid watering for 24 hours after each treatment as well, so the product absorbs through the leaves instead of washing off.
• This is most effective when paired with fertilization and proper watering, which strengthens the grass and reduces future weed pressure naturally

Why You Want Both (And How They Work Together)

Think of pre-emergent and post-emergent as two halves of the same plan.

Here's what a complete program looks like across the season:

• Pre-emergent in early growing season, before weed seeds wake up
• Post-emergent treatments through the growing season, spaced about 30 to 60 days apart, to catch weeds as they appear
• A second pre-emergent in the fall, before winter weeds germinate (skip this round if you're overseeding)

Pre-emergent stops the next generation of weeds from ever existing, which heads off most of the problem before it starts. Post-emergent, applied repeatedly through the season, handles anything that slips through plus any perennial weeds that already had roots in your lawn before the season started.

Run both on this schedule and the difference in your lawn is dramatic. Year over year, weed pressure drops because you're never letting the cycle complete itself. The weeds never get a chance to spread seeds, the grass gets stronger, and the lawn becomes self-defending.

This is the kind of program that turns a lawn around in one or two seasons.

The Spring Timing Problem

If you're reading this in spring, here's the urgent part.

Colorado soil temperatures are rising fast. The window for pre-emergent application is short and it fills up quickly on our schedule every year. We can only treat so many properties before soil temperatures pass the threshold, and once that happens, pre-emergent just isn't as effective.

If you want pre-emergent applied this spring, the time to schedule is now, not in a few weeks.

Post-emergent has a much wider window, spring through early fall, and it works on its own to clear out the weeds you can already see. Pre-emergent is the time-sensitive piece. If you want it working in your favor this year, the spring window is the one you can't afford to miss.

Frequently Asked Questions

Is weed control safe for kids and pets?

Keep children and pets off the lawn until the product has completely dried. Depending on temperature, humidity, and sunlight, that usually takes about 2 to 4 hours. For maximum safety and full absorption, we recommend waiting 24 to 48 hours. It's not that your yard is hazardous for a full day. The product just needs time to dry and absorb, and we'd rather give you the careful answer.

Will weed control hurt my grass?

No. Our post-emergent treatment is a selective herbicide, which means it targets broadleaf weeds like dandelions, clover, and thistle while leaving your turf grass unharmed.

Does it cover my whole property, or just the lawn?

Our pre and post emergent weed control services treat the lawn only. We don't currently offer chemical weed control for beds, rock, mulch, or gravel areas. If weeds in those areas are a problem, hand removal can be handled as part of a cleanup or detail maintenance visit.

Does pre-emergent kill the weeds I already have?

No, and this is the most important thing to understand about it. Pre-emergent only prevents new weeds from germinating. It can't do anything about weeds that have already sprouted. That's the job of post-emergent, which is exactly why a complete program uses both.

I don't see any weeds right now. Do I really need this?

A weed-free lawn is actually the ideal time for pre-emergent. The whole point is to stop weed seeds before they ever sprout. Waiting until you can see weeds means you've already missed the easiest win of the season.

How long until I see results?

For post-emergent, weeds typically start to wither within 7 to 14 days. Weaker weeds can show signs in as little as 3 to 5 days, while tough, established weeds may take more than one application to fully knock out.

Will one treatment fix my weed problem?

Honestly, no, and we'd rather tell you that upfront. The first application kills most of what's there. Some stubborn weeds come back, new seeds blow in, and perennial weeds with established roots take repeat hits. Treatments spaced every 30 to 60 days through the season is what gets you a clean lawn and keeps it that way.

Can you handle creeping charlie?

Yes, but it takes persistence. Creeping charlie is a rhizomatic weed, meaning it spreads through its root system underground. A small patch might have one little strand of roots or a sprawling network, so there's no single answer for how many applications it takes. The key is starting early in the season and treating consistently until it's fully gone.

Can I mow before or after a treatment?

It depends on the treatment. After a pre-emergent application, don't mow for 24 hours so the soil and the barrier aren't disturbed. For post-emergent, the rule covers both sides of the visit. Don't mow for 24 hours before the treatment, because the product is absorbed through the weeds' leaves and freshly cut weeds don't have enough leaf surface for it to work. Then don't mow for 24 hours after, so it has time to fully absorb.

Should I water before or after a treatment?

The two treatments are opposites here. After a pre-emergent application, water anytime, even immediately. Water is what activates the product down into the soil. After a post-emergent application, hold off on watering for 24 hours so the product absorbs through the leaves instead of washing off.

What if it rains right after my treatment?

Usually not a problem once the absorption window has passed. Professional-grade products are designed to hold up. If we ever have reason to believe an application didn't take, we'll come back and check.

Can I use weed and feed on top of your treatments?

We don't recommend it. Weed and feed is just fertilizer plus herbicide, so stacking it on our application risks stressing your turf and can interfere with the pre-emergent barrier. The simplest path is to let us run the program so nothing overlaps or works against itself.

Why is there a flag in my yard after a treatment?

It's a legal requirement. Any product that controls weeds is classified as a pesticide and requires a posted notification flag, even a 100% organic one.

Is there an organic option?

Organic and natural weed control exists and can be effective, though it generally works slower and requires more persistence than professional synthetic products.

How to Get Started

Already an ACA customer? Book your weed control treatments right online, the same way you'd book any other service, in addition to your maintenance plan. Each treatment is booked individually, so you can schedule the full season up front or one application at a time.

New to ACA? There's no quote to wait on. Head to the scheduler, pick the treatments you want, and book each one right online. We'll take it from there.

The earlier we get started, the more weeds we prevent.

Book My Weed Control Services Today!