How to Effectively Get Rid of Crabgrass in St Augustine Grass: The Ultimate Guide

close up photography of grass field

To kill crabgrass in st. Augustine grass, use preemergent herbicides and post-emergent herbicides.

  • Water the lawn deeply, providing 1-2 inches of water per week.
  • Avoid overwatering as it can lead to fungal diseases and weaken the grass.
  • Water the lawn in the morning to allow time for the grass blades to dry and prevent disease.

Crabgrass can quickly invade healthy st. Augustine lawns and have a negative impact on its growth and appearance. Controlling crabgrass is a critical part of lawn maintenance. These invasive weeds grow rapidly, choking out your grass and creating unsightly brown spots in your lawn. Neglecting to address the presence of crabgrass on your lawn can lead to further deterioration. The key to removing crabgrass without damaging your st. Augustine grass is to choose the right herbicides and correctly apply them. In this article, we’ll cover some of the most effective ways to kill crabgrass in st. Augustine grass, the best herbicides to use, and when to apply them.

How to Effectively Get Rid of Crabgrass in St Augustine Grass: The Ultimate Guide


Identify And Inspect The Crabgrass Infestation

Crabgrass can be an unpleasant sight in your yard as it can grow as tall as your regular grass, damaging the aesthetics of your lawn. St. Augustine grass grows best in warm, coastal areas, but it is prone to crabgrass infestations.

In this blog post, we will discuss how to identify and inspect crabgrass infestations in your st. Augustine lawn.

Determine The Areas That Have Been Affected By The Crabgrass

The first step in identifying crabgrass infestation is to figure out which areas of your lawn are affected. Crabgrass tends to grow in areas that are warm and sunny, so check these areas first. It can also grow in spots where the soil has been disturbed.

Note down the areas affected by the infestation.

Inspection Of The Degree Of Crabgrass Infestation In The Yard

After identifying the affected areas, inspect the extent of the infestation. Minor infestations are usually manageable at home, but severe infestations may require professional help. Check if the crabgrass has spread to other parts of the lawn or if it’s concentrated in a specific area.

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Also, inspect if there are any bare spots in the grass where the crabgrass has taken over.

How To Identify Crabgrass In St Augustine Grass

Identifying crabgrass in st. Augustine grass may be difficult if you aren’t familiar with how it looks.

  • Crabgrass blades are wider than st.
  • Crabgrass grows faster and taller than st.
  • If you look closely, crabgrass will have a rough texture, with hair-like extensions along the main stem
  • Crabgrass also has a different root system than st.

By following these pointers, you’ll be able to easily spot crabgrass in your st. Augustine grass, and take steps necessary to kill it.

Remember, the key to preventing crabgrass in your yard is to have a well-maintained lawn. Regular mowing, watering, and fertilization of st. Augustine grass will keep it thick and healthy, making it less likely for crabgrass to take over.

Prepare The Lawn For Crabgrass Removal

Mow And Trim The Grass

Before getting down to crabgrass removal, it is important to prepare the lawn by mowing and trimming the grass. This will ensure that the crabgrass is visible, making it easier to identify and eliminate.

  • Set the mower blade height to 3-4 inches to keep the grass tall and provide shade to the soil, preventing the crabgrass from growing.
  • Use a string trimmer to trim the grass along fence lines and other hard-to-reach areas.
  • Bag the clippings and dispose of them properly to avoid spreading the crabgrass seeds.

Water The Lawn A Few Days Prior To Crabgrass Elimination

Watering the lawn a few days before crabgrass elimination will help loosen the soil and make it easier to remove the crabgrass.

Application Of Herbicide Before Eliminating The Crabgrass

Applying herbicide before eliminating the crabgrass is essential to prevent it from regrowing.

  • Choose a pre-emergent herbicide to prevent the crabgrass from growing or a post-emergent herbicide to kill the crabgrass that is already growing.
  • Read the instructions carefully and follow them to avoid damaging the st augustine grass.
  • Treat the entire lawn to avoid missing any areas where the crabgrass might be hidden.

By preparing the lawn adequately before eliminating the crabgrass, you increase your chances of success in removing it. Remember to follow the given guidelines, and get ready to enjoy your st augustine lawn’s crabgrass-free look.

How to Get Rid of Crabgrass (4 Easy Steps)

Crabgrass Removal Techniques

Crabgrass is a bothersome weed that can quickly invade and overcrowd lawns, leaving them patchy and unsightly. For st augustine grass owners, removing crabgrass can be quite challenging. However, there are several techniques that can be used to effectively control and kill crabgrass.

In this blog, we will go over some of the best crabgrass removal techniques that you can use to ensure your st augustine grass lawn remains healthy and beautiful.

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Hand-Pulling Crabgrass In St Augustine Grass

Hand-pulling crabgrass might seem like a time-consuming and daunting task; it is often the most effective way of removing crabgrass from your st augustine grass lawn. This method is ideal for small infestations.

  • Pull the weed when the soil is moist and the crabgrass roots are shallow.
  • Make sure to remove the entire plant, including the root system, to prevent regrowth.
  • Fill up the holes with fresh soil to cover the gap left by the removed weed.
  • Repeat this process until no crabgrass remains.

Using A Dethatcher

Another efficient way to eliminate crabgrass is by using a dethatcher. The process involves raking your lawn’s surface with a specialized machine that removes unwanted debris, including the crabgrass.

  • Choose a dethatching machine that’s appropriate for the size of your lawn.
  • Follow the manufacturer’s instructions.
  • Thatch when the grass is growing so the lawn can quickly recover from the dethatching.

Using A Hoe Or Rake To Remove Crabgrass

Hoeing or raking is a manual way of getting rid of crabgrass and is best used on smaller lawns with minimal weed infestation.

  • Use a sharp garden hoe to make straight cuts through the crabgrass roots.
  • A rake can also be used to remove the cut crabgrass, which should be disposed of in a plastic bag or bin.
  • Be sure not to damage the st augustine grass, as this could lead to moisture loss and disease susceptibility.

Applying Herbicide To Get Rid Of Crabgrass

Herbicide application is one of the most common and effective ways to control and kill crabgrass in st augustine grass lawns.

  • Read and follow the manufacturer’s instructions carefully.
  • Apply the herbicide when the crabgrass is actively growing.
  • Avoid using excess herbicides that can damage the st augustine grass and other nearby plants.
  • Herbicides can be harmful to pets and people. Keep in mind that you need to protect pets and people from herbicides.

Crabgrass removal can be a challenging task for st augustine grass owners. However, there are several techniques that you can utilize to combat this troublesome weed. Hand-pulling, using a dethatcher, hoeing/raking, and applying herbicides are all effective ways to get rid of crabgrass in your st augustine grass lawn.

Remember, proper lawn maintenance is key to preventing crabgrass from reappearing, it is best to regularly water and fertilize your lawn and keep the lawn mowed.

Preventing The Reoccurrence Of Crabgrass In St Augustine Grass

Crabgrass is a persistent weed that can quickly spread and overtake a st augustine lawn. Once it takes root, it can be challenging to eliminate. However, preventing its reoccurrence is the key to maintaining a healthy, lush lawn. Below are some effective methods for preventing the reoccurrence of crabgrass in st augustine grass.

Proper Maintenance Of The Lawn

Proper maintenance is crucial for keeping st augustine grass healthy and crabgrass-free.

  • Mow the lawn regularly to keep it at a healthy height of 3-4 inches.
  • Water the grass deeply and less frequently to encourage deep root growth.
  • Remove thatch buildup regularly to allow water and nutrients to penetrate the soil.
  • Ensure the lawn receives sufficient sunlight.
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Aeration Of The Lawn

Aerating your lawn can improve soil health, allowing the grass to grow deep roots and making it more resistant to weeds.

  • Aerate the lawn once or twice a year, depending on the soil type.
  • Spring or fall are the best times to aerate.
  • Use an aerator that removes plugs of soil to allow air, water and nutrients to penetrate the soil.
  • Avoid aerating when the ground is too wet or dry.

Fertilizing The Lawn

Fertilizing your lawn can help it grow stronger and keep crabgrass at bay.

  • Use a slow-release nitrogen fertilizer.
  • Apply fertilizer in early spring or early summer for best results.
  • Follow the manufacturer’s instructions for application rates and timing.
  • Do not over-fertilize as it can lead to thatch buildup.

Reseeding The Lawn

Reseeding your lawn can help fill in bare spots and create a thick and dense lawn. A thick lawn can naturally prevent weed growth.

  • Reseed the lawn in the spring or fall.
  • Choose a grass seed mix that is suitable for st augustine grass.
  • Prepare the soil by removing debris and loosening it.
  • Spread the seed evenly and cover it with a thin layer of soil.

The Use Of Pre-Emergent Herbicides

Pre-emergent herbicides can prevent crabgrass seeds from germinating, stopping the weed before it even starts.

  • Apply pre-emergent herbicides in early spring or early fall.
  • Follow the manufacturer’s instructions for application rates and timing.
  • Water the lawn after application to activate the herbicide.
  • Do not use pre-emergent herbicides if you plan to reseed the lawn.

By following these tips, you can effectively prevent the reoccurrence of crabgrass in st augustine grass. Proper lawn maintenance combined with regular aeration, fertilizing, reseeding, and pre-emergent herbicides can result in a healthy and weed-free lawn.

green grass during daytime

Frequently Asked Questions Of How To Kill Crabgrass In St Augustine Grass?

How Does Crabgrass Affect St Augustine Grass?

Crabgrass competes with st augustine grass for sunlight, water, and nutrients, leading to the weakening and thinning of the lawn.

When Is The Best Time To Kill Crabgrass In St Augustine Grass?

It’s best to apply a pre-emergent herbicide before crabgrass germinates in spring, and post-emergent herbicides before it flower and spread seeds.

How Can I Prevent Crabgrass From Growing In St Augustine Grass?

Mow st augustine grass at the correct height, water deeply and infrequently, and apply a pre-emergent herbicide at least a month before the typical emergence of crabgrass in spring.

Should I Manually Remove Crabgrass From St Augustine Grass?

Manual removal of crabgrass can be effective for small infestations. However, removing the entire root system is crucial to prevent it from growing back.


Controlling crabgrass in st augustine grass can be a bit challenging, but by following some basic guidelines, it can be easily handled. Start by ensuring your lawn is well-maintained, feeding it appropriately and providing it with adequate watering. This will help prevent the growth and spread of crabgrass.

In case crabgrass manages to make an appearance, there are several effective methods that can be used to eliminate it, including hand-pulling it, applying pre-emergent herbicides, and using post-emergent herbicides. Always make sure to follow the instructions provided on the herbicides’ labels to get the best results.

By taking these simple steps, you can achieve the lush, green lawn you’ve always wanted with healthy st augustine grass, and keep crabgrass at bay. Remember, patience and consistency are the key to a healthy, beautiful lawn. So go ahead, try out these tips and enjoy the beauty of your crabgrass-free st augustine lawn!