Dealing with crabgrass on your St. Augustine lawn can feel like a constant battle, especially when those stubborn green invaders start creeping in. Having the right Best Crabgrass Killer For St Augustine Grass on hand before it gets out of control makes a huge difference. I've spent the last few months digging into what really works, so you don't have to guess.
After lots of research and sifting through what homeowners are saying, the BASF Drive XLR8 Crabgrass Killer stands out for its effectiveness and targeted approach. This guide will break down the top options, helping you get back to enjoying a lush, weed-free lawn.
Comparison Chart of Best Crabgrass Killer for St Augustine Grass
List of Top 5 Best Crabgrass Killer for St Augustine Grass
When you're looking to get rid of crabgrass, different approaches work best depending on whether you want to prevent it or kill it after it pops up, and how you prefer to apply it. We’ve sifted through user feedback and manufacturer specs to find options that perform well on St. Augustine grass without harming it.
Below are the list of products:
1. BASF Drive XLR8 Crabgrass Killer Lawn
This post-emergent herbicide is designed to tackle crabgrass and other grassy and broadleaf weeds directly after they've already sprouted. Its active ingredient, quinclorac, is known for its effectiveness against crabgrass, and it also offers about 30 days of residual control, meaning it helps prevent new weed seeds from germinating for a while. It's a concentrate, so you'll mix it with water, which can be cost-effective for larger areas.
Why I picked it
BASF Drive XLR8 is highly regarded for its ability to take down established crabgrass without damaging St. Augustine grass, a common concern for homeowners. The quinclorac formulation is a go-to for many lawn care professionals.
Key specs
- Active Ingredient: Quinclorac
- Type: Post-emergent
- Residual Control: Up to 30 days
- Form: Concentrate
- Container Size: 64 Ounces
Real-world experience
Many users report seeing visible results on crabgrass within a few days of application. The concentrate formula allows for flexible application rates, which can be helpful for spot treating smaller areas or treating an entire lawn. It's generally well-tolerated by St. Augustine grass when used according to label directions.
Trade-offs
As a concentrate, it requires careful mixing, and you'll need a sprayer for application. Some users noted it may take a second application for very stubborn or widespread infestations.
2. Ortho GroundClear Weed & Grass Killer
This ready-to-use spray is designed for fast-acting, non-selective weed and grass killing. While it's not specifically formulated only for crabgrass, its broad-spectrum action means it will eliminate it along with many other weeds. It’s important to note that this product is non-selective, meaning it will kill any plant it touches, so careful application is crucial around desirable St. Augustine grass.
It is OMRI Listed, suggesting it aligns with organic gardening principles, though it's still a herbicide.
Why I picked it
The Ortho GroundClear offers a convenient, ready-to-use solution and is effective at eliminating existing weeds quickly. Its OMRI listing is a bonus for those seeking more natural approaches.
Key specs
- Type: Ready-to-use, Non-selective
- Active Ingredients: Vary (often glyphosate and/or other acids)
- Container Size: 1 Gallon (with Comfort Wand dispenser)
- Application: Spray
Real-world experience
Users appreciate the ease of the Comfort Wand, which makes application less labor-intensive. It’s praised for its speed in killing weeds on contact, which can provide a noticeable difference in a lawn fairly rapidly. It's ideal for clearing out unwanted vegetation from patios, driveways, or spot-treating stubborn weeds.
Trade-offs
The primary drawback is its non-selective nature. You must be extremely careful to shield or avoid spraying your St. Augustine grass, as it will also kill desirable turf. It does not offer pre-emergent control.
3. Scotts Halts Crabgrass & Grassy Weed Preventer
This product is a pre-emergent, meaning it's applied before crabgrass seeds germinate to stop them from growing in the first place. It's specifically designed for lawn care and is effective against crabgrass and many other annual grassy weeds. St. Augustine grass can tolerate this product when applied correctly, making it a good choice for proactive lawn care.
It's sold in larger bags, suitable for covering significant areas.
Why I picked it
Scotts Halts is a well-established name in lawn care, and this pre-emergent offers reliable protection against crabgrass before it becomes a problem. It's a solid choice for preventative maintenance.
Key specs
- Type: Pre-emergent
- Target Weeds: Crabgrass, other annual grassy weeds
- Coverage: Up to 10,000 sq. ft.
- Form: Granular
- Weight: 20.12 lbs.
Real-world experience
Many users have success with this product by applying it in early spring, before temperatures consistently reach 55-60°F. It’s straightforward to apply with a broadcast spreader, and it creates a barrier that prevents crabgrass seeds from successfully sprouting. It’s often a key component of a well-rounded lawn care program.
Trade-offs
This product is preventative only; it will not kill crabgrass that has already sprouted. It requires application at the right time of year for effectiveness.
4. Scotts Turf Builder Triple Action1
This product offers a multi-pronged approach to lawn care. It combines weed control, weed killer, crabgrass preventer, and lawn fertilizer all in one product. This means it can act as a pre-emergent, killing crabgrass before it starts, and also tackle existing weeds, including some broadleaf varieties, while simultaneously feeding your St. Augustine grass.
It’s a convenience product designed to simplify lawn maintenance.
Why I picked it
The "all-in-one" convenience of Scotts Turf Builder Triple Action1 is a huge draw for homeowners who want to tackle multiple tasks with a single application. Its ability to both prevent and kill crabgrass is a significant advantage.
Key specs
- Type: Pre-emergent and Post-emergent
- Functions: Weed Control, Lawn Weed Killer, Crabgrass Preventer, Grass Fertilizer
- Coverage: Up to 4,000 sq. ft.
- Form: Granular
- Weight: 11.31 lbs.
Real-world experience
Users find this product effective for its intended purposes, providing a good balance of weed prevention, weed killing, and turf fertilization. It’s particularly useful in early spring when combining tasks is most beneficial. The fertilizer component helps the St. Augustine grass recover and thrive.
Trade-offs
As a combined product, its efficacy on specific weeds might not be as potent as a dedicated single-purpose herbicide. It also requires prompt application once the bag is opened for best results and should be applied with a spreader.
5. Scotts Turf Builder Weed and Feed5
Similar to Triple Action, this product combines weed control, weed killer, and lawn fertilizer, but it specifies control of dandelion and clover along with broader weed suppression. While it doesn't explicitly state crabgrass prevention, it's designed to handle many common lawn weeds. For St. Augustine grass, it's important to use it when the grass is actively growing and temperatures are within the recommended range to avoid damage.
Why I picked it
Scotts Turf Builder Weed and Feed5 is a classic lawn treatment that many people rely on for its dual action of killing existing weeds and fertilizing the lawn, promoting healthier turf growth.
Key specs
- Type: Post-emergent (for listed weeds), Fertilizer
- Target Weeds: Dandelion, Clover, and other lawn weeds
- Coverage: Up to 4,000 sq. ft.
- Form: Granular
- Weight: 11.32 lbs.
Real-world experience
This product is a popular choice for homeowners looking for a straightforward way to improve their lawn's appearance by removing weeds and giving it a nutrient boost. It helps St. Augustine lawns thicken up, making it harder for weeds to establish. Many users find it effective for general weed problems.
Trade-offs
It’s not specifically a crabgrass killer, so if crabgrass is your primary concern, a product like BASF Drive XLR8 might be more targeted. Like other weed and feed products, application timing is critical to avoid harming St. Augustine grass, especially during hot or dry periods.
How I picked
When I set out to find the best crabgrass killers for St. Augustine grass, my main focus was efficacy and safety for this particular turf type. St. Augustine grass can be sensitive, especially to certain herbicides, so identifying products that target crabgrass without severely damaging the lawn was paramount.
I evaluated several factors:
- Active Ingredients: I looked for products with ingredients known to be effective against crabgrass while also researching their safety profiles for St. Augustine grass. Ingredients like quinclorac are often recommended for post-emergent control on this type of turf.
- Pre-emergent vs. Post-emergent: I considered both types because a good lawn care strategy often involves both prevention and treatment. Pre-emergents stop crabgrass before it starts, while post-emergents kill it after it has already sprouted.
- Formulation Type: Whether a product is a concentrate that needs mixing, a ready-to-use spray, or a granular application can significantly impact ease of use and effectiveness. I considered how each might fit into a typical homeowner’s routine.
- User Feedback and Reviews: I analyzed aggregated user reviews, paying close attention to comments from St. Augustine grass owners. This helps identify real-world performance and any unexpected side effects.
- Manufacturer Claims and Specifications: I cross-referenced product labels and manufacturer details to ensure the claims of efficacy and safety were supported by the product's stated purpose and ingredients.
I didn't test long-term durability beyond the product's stated residual control periods, nor did I perform extensive soil analysis, as my focus was on the direct impact of the weed killer on crabgrass and St. Augustine grass health.
Buying guide — what actually matters for Best Crabgrass Killer For St Augustine Grass
Figuring out the right crabgrass killer for your St. Augustine lawn comes down to a few key considerations. It’s not just about grabbing the first bottle you see; understanding these factors will help you make the best choice for a healthy, green yard.
Pre-emergent vs. Post-emergent Control
This is probably the biggest decision you'll make. Pre-emergent herbicides are applied in early spring before crabgrass seeds germinate. They create a barrier in the soil that stops seeds from sprouting. If you have a history of crabgrass, this is your best bet for prevention.
Post-emergent herbicides, on the other hand, are for killing crabgrass that has already grown. They work best when applied soon after you spot the first few weeds.
Active Ingredients and Lawn Safety
Not all herbicides are created equal, and St. Augustine grass can be sensitive. Look for products that specifically mention being safe for St. Augustine grass when used as directed.
Ingredients like quinclorac are often good choices for post-emergent crabgrass control on this type of turf. Avoid broad-spectrum non-selective herbicides if you only want to target crabgrass, as they can damage your lawn too.
Ease of Application
How do you prefer to treat your lawn? Some products are ready-to-use sprays, perfect for spot treatment or smaller lawns where you can carefully apply them. Others come as concentrates that you mix with water and apply using a hose-end or backpack sprayer. Granular products are usually spread using a broadcast or drop spreader and often double as fertilizer.
Your choice here will depend on your equipment and how much time you want to spend.
Coverage Area and Value
Products are sold in different sizes and are designed to cover specific square footage. Consider the size of your lawn. Buying a concentrate might offer better value for larger areas since you can dilute it as needed. For smaller yards or spot treatment, a ready-to-use spray might be more convenient and less wasteful.
Always check the product label for coverage estimates to ensure you get enough for your needs.
Timing is Everything
Both pre-emergent and post-emergent treatments have optimal application windows. For pre-emergents, this is typically in early spring, before soil temperatures consistently reach 55-60°F for several days in a row, and before you see any crabgrass sprouts. Post-emergents are most effective when applied to young, actively growing crabgrass. Applying herbicides too late in crabgrass's life cycle can reduce their effectiveness.
Frequently Asked Questions (FAQ)
Can I use a general weed killer on St. Augustine grass?
Generally, it's best to use weed killers specifically labeled as safe for St. Augustine grass. Many general weed killers are non-selective, meaning they will kill any plant they touch, including your desired turf. If a product is not specifically recommended for St.
Augustine grass, proceed with extreme caution and consider spot testing in an inconspicuous area first. Some post-emergent herbicides like those containing quinclorac are formulated to target crabgrass while being safer for St. Augustine.
When is the best time to apply crabgrass killer to St. Augustine grass?
The best time depends on whether you're using a pre-emergent or post-emergent. For pre-emergent control, apply in early spring, typically before soil temperatures consistently reach 55-60°F. This is often around the time forsythia bushes bloom. For post-emergent control, apply as soon as you see the first few crabgrass sprouts, usually in late spring or early summer.
Applying when temperatures are extremely hot (above 85-90°F) can stress St. Augustine grass, so it's often best to treat in the cooler parts of the day or during milder weather.
How do I know if crabgrass killer is working?
With post-emergent herbicides, you'll typically see the crabgrass start to yellow and die within a few days to a week after application, depending on the product and the size of the weeds. For pre-emergents, proof that it's working is the absence of crabgrass throughout the growing season. If you're not seeing new crabgrass sprout, the pre-emergent barrier is doing its job. Always follow label instructions for reapplication if needed.
Is it safe to fertilize my St. Augustine grass at the same time I apply crabgrass killer?
Some products, like the Scotts Turf Builder Triple Action1 and Weed and Feed5 mentioned, combine fertilizer with weed control. These are formulated for simultaneous application. However, if you're using a separate crabgrass killer and fertilizer, it's usually best to wait a week or two between applications to avoid stressing your lawn. St.
Augustine grass prefers not to be fertilized when it's already under stress from weed treatments or extreme temperatures. Always check the product labels for specific instructions.
Final verdict
For effective and safe crabgrass management on your St. Augustine lawn, the BASF Drive XLR8 Crabgrass Killer Lawn stands out as the top choice for post-emergent control, tackling existing weeds without harming your grass. If you prefer a proactive approach, Scotts Halts Crabgrass & Grassy Weed Preventer offers excellent pre-emergent protection. For those seeking convenience that tackles multiple lawn issues at once, Scotts Turf Builder Triple Action1 provides a good blend of prevention, weed killing, and fertilization.
Affiliate disclosure: This post contains affiliate links. If you buy through one of these links, I may earn a small commission at no extra cost to you. It never changes my recommendation, I only suggest gear I'd actually buy myself.