
If you’re like most homeowners, you’ve probably caught yourself staring out at the yard and wondering, “How do I keep those annoying weeds from popping up this year?” or “When should I fertilize my lawn?” These are exactly the types of questions that crop up every spring as we shake off winter and start dreaming of lush, green grass. If this sounds like you, then you’ve landed in the right place.
Welcome to our complete, They Ask, You Answer guide on using lawn fertilizer with pre-emergent this spring. Here, we’ll break down why spring is an ideal time to tackle weeds before they become a real headache, how pre-emergent products work, and why it’s so effective to combine fertilizer and pre-emergent in one go. We’ll also dive into a bit of the “why” behind the science—without getting too geeky.
By the end of this blog, you’ll not only know how to keep weeds under control, you’ll also feel confident about giving your grass a strong nutritional boost to thrive all season long.
What Is Pre-Emergent and How Does It Work?
Before we get into the nitty-gritty of when and how to apply pre-emergent, let’s tackle the fundamental question:
What exactly is pre-emergent?
- A pre-emergent herbicide is a lawn care product designed to stop weed seeds from germinating. Essentially, it forms a protective barrier in the upper layer of soil, inhibiting the growth of pesky annual weeds like crabgrass and foxtail.
How does it work?
- The science behind pre-emergent is fairly straightforward: once applied, it lingers near the surface of the soil. When weed seeds begin to sprout, the emerging seedling encounters the herbicide barrier, preventing root or shoot development. This halts the weed before it can break through the soil and spread.
In other words, pre-emergent targets weeds at their most vulnerable stage—before they’re visible. This proactive approach means you’ll spend less time pulling weeds later in the season.

Why Spring Is the Best Time for Pre-Emergent
If you’re looking for the best time to apply pre-emergent for the most effective results, spring is your golden window—especially in climates with a clear seasonal shift from cold to warming temperatures. Here’s why:
- Weeds Are About to Wake Up: As soil temperatures start to rise (usually reaching around 55°F for several consecutive days), weed seeds begin germinating.
- Preventative Strike: By applying pre-emergent just before—or right as—these seeds activate, you’re effectively stopping the weeds from ever seeing the light of day.
- Healthy Turf Competition: Spring is also a prime time for grass growth. Giving your lawn a head start with nutrients and weed prevention helps your grass outcompete any lingering weeds.
Tip: Watch for early spring cues like consistent daytime temperatures above 60°F, emerging spring bulbs, or even the blooming of local trees—these signs often hint that it’s time to get that pre-emergent down.
The Science of Weed Germination (Without Getting Too Geeky)

Let’s get a bit sciency—just enough to understand what’s going on under the surface:
- Germination Trigger: Weed seeds are highly responsive to soil temperature and moisture. Once these conditions are right, they’ll quickly sprout roots and shoots.
- Chemical Barrier: Pre-emergent herbicides contain active ingredients (like prodiamine or pendimethalin) that disrupt a weed’s cell division or root development process.
- Timing Is Everything: If you apply pre-emergent too early, it might degrade before the weeds sprout. Too late, and you’ll already have baby weeds popping up through the soil. Hitting that sweet spot is key.
The bottom line: pre-emergent essentially stalls weed growth at the cellular level, before you see any leaves or stems. This is why it’s vastly different (and often more efficient) than post-emergent, which targets weeds after they’ve sprouted.
What About Fertilizer? Why Combine It with Pre-Emergent?
Now that we know how pre-emergent works, let’s look at why adding fertilizer to the mix can be a game-changer:
- Jumpstart Your Grass: Spring is the “growth spurt” season for most turf grasses. By fertilizing early, you’re ensuring your lawn has the nutrients (like nitrogen, phosphorus, and potassium) it needs to grow strong and healthy.
- Outcompete Weeds: A thick, well-fed lawn is one of the best defenses against weed infiltration. Weeds struggle to gain a foothold when your grass is dense and robust.
- Convenience: Many lawn care products now combine a weed preventer (pre-emergent) with fertilizer, saving you time (and often money) by only requiring one application instead of two.
When these two strategies—preventing weeds and feeding your lawn—happen simultaneously, you’re essentially setting the stage for a weed-free, nutrient-rich environment. That’s the core reason spring fertilizer with pre-emergent is such a hot topic among homeowners.

When Exactly Should You Apply a Lawn Fertilizer with Pre-Emergent?
They Ask: When to apply pre-emergent for best results?
We Answer: It depends on this year’s weather, but a general rule of thumb is to apply just before weed seeds begin to germinate. This can be anywhere from late February to early April.
- Check Soil Temps: If possible, take a quick measurement of your soil. When it’s consistently around 50–55°F, it’s time to break out the spreader.
- Look at the Forecast: A stretch of mild weather is ideal for application. Avoid applying right before heavy rains, which can wash the product away or dilute it.
- Follow the Label Instructions: Every product is a bit different. Some pre-emergents require watering in immediately; others need a slight delay. Always read the label carefully.
Pro Tip: If you miss this early spring window, don’t panic. You can still apply a late-spring or even early-summer pre-emergent, but know that some weeds might already have slipped past the barrier.
Step-by-Step: A Simple Spring Lawn Care Schedule

If you’re feeling overwhelmed, here’s a basic spring lawn care timeline you can follow:
Early Spring (Late February–March)
- Clean-Up: Remove debris, twigs, and leaves from the lawn.
- Soil Test (Optional): If you’re unsure of your lawn’s pH or nutrient needs, a simple soil test can guide your fertilizer choices.
Pre-Emergent & Fertilizer Application (March–April)
- Spread a Combination Product: Look for a bag that says “Weed Preventer + Lawn Fertilizer.” Follow the recommended application rate.
- Water In: Most products work best when watered in after application, helping the chemical settle into the soil.
Mid to Late Spring (April–May)
- Monitor Weeds: If you see early signs of weeds that slipped through, tackle them with a post-emergent spot treatment.
- Mow Regularly: Keep your grass at the recommended height for your grass type (usually around 3.5 inches for fescue).
Ongoing
- Light Watering: If rainfall is scarce, ensure your lawn gets about 1 inch of water per week.
- Summer Prep: You might consider a second round of fertilizer or another pre-emergent if you have a particularly stubborn weed problem.
FAQs About Spring Fertilizer and Pre-Emergent
Q: Is it too late if I already see weeds?
A: If you’re seeing weeds, pre-emergent won’t do much for those that have already sprouted. Instead, you may need a post-emergent herbicide for any existing weed growth. But pre-emergent can still help prevent further weed germination.
Q: Do I need to water in pre-emergent immediately?
A: Many products recommend light watering shortly after application to help the pre-emergent reach the top layer of soil. However, always check the product label. Some might advise waiting a day or two.
Q: How often should I fertilize my lawn?
A: This can vary based on grass type, soil quality, and ultimately how you want your lawn to look. If you want a golf course style lawn, then you’ll need all 5 yearly applications, but for many homeowners, two to four applications per year (including the spring) can keep your lawn in fairly good shape. Just avoid over-fertilizing, which can lead to runoff and “burning” the turf.
Q: What if I have newly seeded areas?
A: Pre-emergent can also prevent your desirable grass seed from germinating. If you’re planning to overseed your lawn in spring, look for specialty products that are safe for new grass seed, or postpone pre-emergent until after your new grass has established.
Putting It All Together for a Weed-Free, Lush Lawn
Applying a lawn fertilizer with pre-emergent in spring is the ultimate one-two punch for a weed-free, vibrant yard. Here’s why it works so well:
- Prevention: It stops weeds before they can rear their ugly heads.
- Nutrition: It jumpstarts grass growth with essential nutrients.
- Efficiency: It saves time by combining two critical lawn treatments in one.
When you tackle both weed prevention and fertilization at the start of the growing season, you’re setting your lawn up for success right from the get-go. As temperatures warm, you’ll see your grass flourish while your weed woes stay minimal—exactly what every homeowner wants.

Why Partner with a Professional Lawn Fertilization and Weed Control Program?
We get it—life is busy. If the idea of measuring soil temperature, hauling fertilizer bags, and timing your pre-emergent perfectly sounds daunting, you’re not alone. That’s why our team offers a lawn fertilization and weed control program that takes the guesswork (and the heavy lifting) off your plate.
- Tailored to Your Lawn: We assess your yard’s specific grass type, soil conditions, and weed challenges.
- Pro-Level Products: We use professional-grade fertilizers and pre-emergent herbicides designed to maximize results.
- Timing and Technique: We apply treatments at the optimal times, making sure your lawn gets exactly what it needs, when it needs it.
A great-looking lawn shouldn’t be a hassle. With our help, you can spend more time enjoying your yard, rather than worrying about crabgrass or thin, lackluster turf.
Ready to Keep Weeds at Bay This Spring?
If you have more questions about how to use lawn fertilizer with pre-emergent—or you’re ready for a hassle-free way to maintain a lush, healthy lawn—reach out to us. Our team is here to answer any questions you have about your yard. Remember, there’s no such thing as a silly question when it comes to protecting your lawn from weeds and ensuring it’s nourished for the season ahead.
Get in touch, and let’s talk about how our lawn fertilization and weed control program can give you the beautiful, weed-free grass you’ve been dreaming of. After all, with the right springtime approach, you’re only a few steps away from enjoying the greener side of life all season long.