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Keeping your St. Augustine grass looking lush and weed-free can feel like a never-ending battle. I know the feeling! I spent one summer pulling weeds almost daily, and it felt like they were multiplying faster than I could remove them. Fortunately, there are some effective weed killers out there that won’t harm your precious St. Augustine. Finding the right one makes all the difference. This guide will walk you through some of the best options to help you reclaim your lawn.
Product Overview
- Ortho WeedClear Weed Killer for Lawns: Best overall, effective on a wide range of weeds.
- Southern Ag Amine 2,4-D Weed Killer: Best for broadleaf weeds, economical concentrate.
- Spectracide Weed Stop For Lawns Plus Crabgrass Killer: Best for crabgrass control, also tackles other common weeds.
- BioAdvanced Weed Killer for Lawns: Best for sensitive St. Augustine lawns, gentle formula.
- Tenacity Turf Herbicide: Best for stubborn weeds, professional-grade selective herbicide.
Top 5 Best Weed Killer For St Augustine
1. Ortho WeedClear Weed Killer for Lawns
Ortho WeedClear is a popular choice for homeowners because it’s effective on a wide range of common lawn weeds. It’s a ready-to-use formula that’s easy to apply with a sprayer, and it starts working quickly to kill weeds down to the root. It’s designed to be safe for St. Augustine grass when used as directed.
Pros:
- ✅ Kills a wide variety of weeds, including dandelions, clover, and chickweed.
- ✅ Ready-to-use formula, no mixing required.
- ✅ Rainproof in one hour.
Cons:
- ❌ Can be expensive compared to concentrated formulas.
- ❌ May require multiple applications for tougher weeds.
- ❌ Some users report slight discoloration of grass in small areas.
Verdict: A solid choice for most homeowners looking for a convenient and effective weed killer for their St. Augustine lawn. It’s especially good for those who don’t want to deal with mixing concentrates.
2. Southern Ag Amine 2,4-D Weed Killer
Southern Ag Amine 2,4-D is a cost-effective solution for controlling broadleaf weeds in your St. Augustine lawn. It’s a concentrated formula, so you’ll need to mix it with water before applying, but a little goes a long way. This makes it an economical option for larger lawns or for treating weeds on a regular basis.
Pros:
- ✅ Economical concentrate formula.
- ✅ Effective on a wide range of broadleaf weeds, such as dollarweed and clover.
- ✅ Can be used on other types of grass, offering versatility.
Cons:
- ❌ Requires careful mixing and application to avoid damaging the lawn.
- ❌ Can be harmful to other plants if not applied carefully.
- ❌ Strong odor during and after application.
Verdict: Best for those who need to treat a large area or who are comfortable mixing and applying concentrated herbicides. It offers excellent value for the money.
3. Spectracide Weed Stop For Lawns Plus Crabgrass Killer
Crabgrass can be a real nuisance in St. Augustine lawns, and Spectracide Weed Stop is designed to tackle it effectively. It also controls other common lawn weeds, making it a versatile choice for overall weed control. This product is available in ready-to-use and concentrate formulas.
Pros:
- ✅ Effective at killing crabgrass and other grassy weeds.
- ✅ Controls a wide range of broadleaf weeds.
- ✅ Available in both ready-to-use and concentrate formulas.
Cons:
- ❌ May require multiple applications for complete crabgrass control.
- ❌ Can stain concrete or other surfaces if not cleaned up immediately.
- ❌ Can be harsh on stressed lawns, use with caution during hot weather.
Verdict: A good option for homeowners struggling with crabgrass infestations in their St. Augustine lawns. It provides broad-spectrum weed control and comes in convenient application options.
4. BioAdvanced Weed Killer for Lawns
If you have a sensitive St. Augustine lawn or are concerned about harsh chemicals, BioAdvanced Weed Killer for Lawns is a gentler option. It’s formulated to kill weeds without harming your grass, and it’s effective on a variety of common lawn weeds. I’ve personally used this on a section of my yard that’s a bit more delicate, and it worked well without causing any damage.
Pros:
- ✅ Gentle formula that’s less likely to harm St. Augustine grass.
- ✅ Effective on common lawn weeds like dandelions and clover.
- ✅ Rainfast in one hour.
Cons:
- ❌ May not be as effective on tougher weeds as stronger herbicides.
- ❌ Can be more expensive than other options.
- ❌ May require more frequent applications to maintain weed control.
Verdict: Ideal for those who prioritize safety and gentleness on their St. Augustine lawn. It’s a good choice for maintaining a weed-free lawn without the risk of harsh chemicals.
5. Tenacity Turf Herbicide
Tenacity Turf Herbicide is a professional-grade selective herbicide that’s known for its effectiveness on stubborn weeds that other products can’t control. While it’s more expensive and requires a bit more knowledge to use properly, it can be a game-changer for lawns with persistent weed problems. I’ve seen this recommended by lawn care professionals for particularly difficult situations.
Pros:
- ✅ Highly effective on a wide range of stubborn weeds, including bentgrass and nimblewill.
- ✅ Can be used for pre-emergent and post-emergent weed control.
- ✅ Selective formula that won’t harm desirable grasses when used correctly.
Cons:
- ❌ More expensive than other weed killers.
- ❌ Requires careful mixing and application, and proper PPE.
- ❌ Can temporarily whiten the grass for a few days after application.
Verdict: Best for experienced users or those with serious weed problems that other products can’t solve. It’s a powerful tool that can provide excellent weed control when used correctly.
Buying Guide
Choosing the right weed killer for your St. Augustine lawn involves considering several factors. Here are some tips to help you make the best decision:
- Identify the weeds: Different weed killers are effective on different types of weeds. Knowing what weeds you’re dealing with will help you choose a product that targets them specifically.
- Consider your lawn’s sensitivity: St. Augustine grass can be sensitive to some herbicides. Look for products that are specifically labeled as safe for St. Augustine lawns, or opt for a gentler formula if you’re concerned about damage.
- Read the label carefully: Always read and follow the instructions on the product label. This will help you avoid damaging your lawn and ensure that the weed killer is used safely and effectively.
- Choose the right application method: Weed killers are available in ready-to-use, concentrated, and granular forms. Choose the application method that’s most convenient for you and appropriate for the size of your lawn.
- Consider the weather: Avoid applying weed killers on windy days or when rain is expected, as this can reduce their effectiveness and potentially harm other plants.
- Think about pre-emergent vs. post-emergent: Pre-emergent herbicides prevent weeds from sprouting, while post-emergent herbicides kill existing weeds. Determine which type is best for your needs based on the current state of your lawn.
FAQs
Q: Can I use any weed killer on St. Augustine grass?
A: No, not all weed killers are safe for St. Augustine grass. Some herbicides can damage or kill St. Augustine. Always choose a product that is specifically labeled as safe for St. Augustine lawns.
Q: How often should I apply weed killer to my St. Augustine lawn?
A: The frequency of application depends on the product and the severity of your weed problem. Generally, you should apply weed killer as needed, following the instructions on the product label. Avoid over-applying, as this can damage your lawn.
Q: What’s the best time of year to apply weed killer?
A: The best time to apply weed killer is typically in the spring and fall when weeds are actively growing, but temperatures are moderate. Avoid applying weed killer during the hottest part of the summer or when your lawn is stressed.
Q: Can I apply weed killer after mowing my lawn?
A: It’s generally recommended to wait a few days after mowing before applying weed killer. This allows the grass to recover from the mowing and reduces the risk of damaging it with the herbicide.
Q: How long should I wait to water my lawn after applying weed killer?
A: The amount of time you should wait to water your lawn after applying weed killer depends on the product. Some products require a waiting period of 24-48 hours, while others are rainfast within a few hours. Check the product label for specific instructions.
Conclusion
Choosing the right weed killer for your St. Augustine lawn can make a huge difference in its overall health and appearance. Whether you’re dealing with a few pesky weeds or a full-blown infestation, there’s a product out there that can help. Remember to consider your lawn’s sensitivity, identify the weeds you’re dealing with, and always follow the instructions on the product label. With a little bit of knowledge and the right weed killer, you can have a lush, weed-free St. Augustine lawn that you can be proud of.
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