Crabgrass can be a real pain, especially if you’re trying to keep your St. Augustine grass looking pristine. This type of grass is beautiful but also sensitive, so you can’t just use any weed killer. I’ve spent years battling weeds in my own lawn, and I know how frustrating it is to find something that works without harming your precious St. Augustine. That’s why I’ve put together this list of the best crabgrass killers specifically designed for St. Augustine grass. Let’s get your lawn looking its best!
Product Overview / Quick Summary:
- Spectracide Weed Stop for Lawns Plus Crabgrass Killer: A dependable, broad-spectrum herbicide that is effective for use on St. Augustine grass.
- BioAdvanced Weed Killer for Lawns: This product offers both pre-emergent and post-emergent control, preventing new weeds while killing existing ones.
- Ortho Weed B Gon Weed Killer for Lawns: Known for its fast-acting formula, it quickly eliminates crabgrass without harming St. Augustine grass.
- Southern Ag Amine 2,4-D Weed Killer: A versatile and economical option, effective against a wide range of broadleaf weeds, including crabgrass.
- PBI/Gordon SpeedZone Lawn Weed Killer: Delivers rapid results, targeting tough weeds effectively and quickly.
Top 5 Best Crabgrass Killers for St. Augustine Grass
1. Spectracide Weed Stop for Lawns Plus Crabgrass Killer
Spectracide Weed Stop is designed to target a wide range of lawn weeds, including crabgrass, dandelions, and clover. It’s formulated to be safe for use on St. Augustine grass when used as directed, making it a popular choice for homeowners.
Pros:
- ✅ Broad-spectrum weed control.
- ✅ Safe for St. Augustine when used as directed.
- ✅ Readily available at most garden centers.
Cons:
- ❌ May require multiple applications for stubborn weeds.
- ❌ Can stain concrete if not cleaned up immediately.
- ❌ Effectiveness may vary depending on weed type and maturity.
Verdict: A solid choice for homeowners seeking a readily available, broad-spectrum weed killer that is safe for St. Augustine grass, just be prepared for possible repeat applications.
2. BioAdvanced Weed Killer for Lawns
BioAdvanced Weed Killer offers both pre-emergent and post-emergent control, meaning it prevents new weeds from sprouting while also killing existing ones. This dual-action approach can be particularly helpful in managing crabgrass in St. Augustine lawns.
Pros:
- ✅ Provides both pre- and post-emergent weed control.
- ✅ Can prevent crabgrass from returning.
- ✅ Offers long-lasting protection.
Cons:
- ❌ Can be more expensive than other options.
- ❌ Requires careful application to avoid harming desirable grasses.
- ❌ May not be as effective on very mature crabgrass.
Verdict: Ideal for those looking for a comprehensive solution that not only kills existing crabgrass but also prevents future infestations, but it requires careful application.
3. Ortho Weed B Gon Weed Killer for Lawns
Ortho Weed B Gon is known for its fast-acting formula that quickly eliminates crabgrass and other common lawn weeds. It’s specifically designed to be safe for use on St. Augustine grass, providing peace of mind during application.
Pros:
- ✅ Fast-acting formula.
- ✅ Won’t harm St. Augustine grass when used as directed.
- ✅ Easy to apply with a hose-end sprayer.
Cons:
- ❌ May not be effective on all types of weeds.
- ❌ Can be less effective in very hot or dry conditions.
- ❌ May require reapplication for complete control.
Verdict: A good choice for those who want to see quick results without damaging their St. Augustine lawn, though it might need a second application for full control.
4. Southern Ag Amine 2,4-D Weed Killer
Southern Ag Amine 2,4-D Weed Killer is a versatile and economical option for controlling a wide range of broadleaf weeds, including crabgrass. Its concentrated formula makes it a cost-effective solution for larger lawns.
Pros:
- ✅ Economical and cost-effective.
- ✅ Effective against a broad range of broadleaf weeds.
- ✅ Can be used on various types of lawns, including St. Augustine.
Cons:
- ❌ Requires careful mixing and application.
- ❌ Can be harmful to other plants if not used properly.
- ❌ May have a strong odor during and after application.
Verdict: Best for homeowners with larger lawns who need an affordable and effective solution, but be sure to follow the instructions carefully to avoid damaging other plants.
5. PBI/Gordon SpeedZone Lawn Weed Killer
PBI/Gordon SpeedZone Lawn Weed Killer delivers rapid results, targeting tough weeds effectively and quickly. This product is formulated for use in various lawn types, including St. Augustine, and is known for its ability to control even the most stubborn weeds.
Pros:
- ✅ Delivers very fast results.
- ✅ Effective on tough and stubborn weeds.
- ✅ Can be used in cooler weather.
Cons:
- ❌ More expensive than some other options.
- ❌ Can cause temporary discoloration of grass.
- ❌ Requires careful application to avoid harming desired plants.
Verdict: Great for homeowners who need a fast-acting solution for tough weeds, especially in cooler climates, but be aware of potential temporary discoloration of the grass.
Buying Guide
Choosing the right crabgrass killer for your St. Augustine lawn involves considering a few key factors. Here’s what you should keep in mind:
- Type of Weed Killer: Decide between pre-emergent and post-emergent options. Pre-emergent herbicides prevent crabgrass seeds from germinating, while post-emergent herbicides kill existing crabgrass.
- St. Augustine Compatibility: Always choose a product specifically labeled as safe for St. Augustine grass. Some herbicides can harm or kill this sensitive grass type.
- Ingredients: Look for active ingredients like 2,4-D, dicamba, or MSMA, but ensure they are formulated in a way that’s safe for St. Augustine.
- Application Method: Consider whether you prefer a granular or liquid application. Granular herbicides are typically applied with a spreader, while liquid herbicides can be sprayed.
- Coverage Area: Check the product label for the coverage area to ensure you buy enough to treat your entire lawn.
- Timing: Apply pre-emergent herbicides in early spring before crabgrass germinates. Apply post-emergent herbicides when crabgrass is actively growing.
- Weather Conditions: Avoid applying herbicides on windy days or when rain is expected, as this can reduce their effectiveness and potentially harm other plants.
- Read the Label: Always read and follow the product label instructions carefully. This will help you achieve the best results and avoid damaging your lawn.
FAQs
Q: Will crabgrass killer hurt my St. Augustine grass?
A: Some crabgrass killers can harm St. Augustine grass, so it’s crucial to choose a product specifically labeled as safe for this type of grass. Always follow the product instructions carefully.
Q: When is the best time to apply crabgrass killer?
A: For pre-emergent herbicides, apply in early spring before crabgrass seeds germinate. For post-emergent herbicides, apply when crabgrass is actively growing, usually in late spring or early summer.
Q: How often should I apply crabgrass killer?
A: It depends on the product and the severity of the infestation. Some products require a single application, while others may need multiple applications. Refer to the product label for specific instructions.
Q: Can I use a general weed killer on crabgrass?
A: General weed killers may not be effective on crabgrass and can potentially harm your St. Augustine grass. It’s best to use a product specifically designed for crabgrass control that is safe for St. Augustine.
Q: What else can I do to prevent crabgrass?
A: Maintain a healthy, dense lawn by mowing high, fertilizing properly, and watering deeply but infrequently. A thick lawn will naturally choke out crabgrass and other weeds.
Conclusion
Dealing with crabgrass in your St. Augustine lawn can be a challenge, but with the right product and approach, it’s definitely manageable. Each of the crabgrass killers discussed offers unique benefits, so consider your specific needs and lawn conditions when making your choice. Whether you need fast-acting results, comprehensive prevention, or an economical solution, there’s a product on this list that can help you achieve a weed-free lawn.
This site contains affiliate links. As an Amazon Associate, I earn from qualifying purchases. This means if you click on a link and buy a product, we may receive a small commission at no extra cost to you.
