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How to Keep Weeds out of Bermuda Grass — Complete Guide

How to Keep Weeds out of Bermuda Grass — Complete Guide

Bermuda grass is prized for its resilience. This is the garden turf for family gardens in need of a tough grass that can withstand the rough and tumble of kids running around. 

It’s commonly used on sports fields, golf fairways, and in parks. It is a warm season grass that grows fast, but it is a high maintenance turf. This isn’t a grass that only needs an occasional mowing. 

It needs frequent mowing, at different heights, and seasonal fertilizing to encourage strong grass blades. Strong enough to choke out any weeds that try to compete for nutrients.


How to keep weeds out of Bermuda grass 

To keep Bermuda grass free from weeds, pre-emergent herbicides need applied at least twice annually. Keeping the soil fertilized and the Bermuda sprigs mowed to a height of 1.5 inches to 2-inches helps it outcompete even the most invasive weeds for nutrients in the soil. 


Identifying the type of weeds that needs to be killed to control 

To keep weeds out, you need to kill what’s already there. Before you can kill a weed, you need to know what you’re fighting – or what weeds are going to fight your Bermuda grass for nutrients from the soil. 


Weed classifications

Any undesirable plant has the potential to be a weed so there are distinctions to be made. Even Bermuda grass is considered a weed by some gardeners. The ones who don’t want it. 

There are three general categories of weeds:


Grass weeds 

Bermuda grass itself is an example of a grass weed. It’s a fast spreader that is an actual grass. Not one that only looks like a grass. 

Examples of these grass types are crabgrass, goosegrass, and foxtails. 


Grass-like weeds 

These look like grass but don’t grow the same. Examples of these are onion grass, nutsedge, and blue grass (poa annua). These grow taller more than they spread. They look like clumps of tall grass blades.


Broadleaf weeds

Broadleaf weeds are the type most people are familiar with. The weeds look more like plants than they do grass blades. They have a stem and a few broad leaves on each.

Examples of these are clover, chickweed, bittercress, and dandelion.


Winter weed control 

In the winter, Bermuda grass goes dormant. All you should see is a blanket of brown. No green. Any green you do see will be weeds. 

Common winter weeds are henbit, crabgrass, nutsedge, and bluegrass (poa annua). 

Dig those out in the winter, making sure you get the entire root of each. 


Apply a pre-emergent herbicide in early spring, then repeat in fall

Early spring and late fall are when to hit Bermuda grass with a pre-emergent herbicide. 

Applying this in winter will have a higher fail rate because you need weeds to be actively growing to soak in the chemicals that are going to kill them. 

Ideal temperatures for applying any herbicide are over 55-Farhenheit. 

Read the labels though because different products require different temperatures. If the soil temperature drops below 70-Fahrenheit, or there’s a dry spell that prevents the herbicide being watered deep into the soil, it won’t be effective. 


How to choose the right weed killer to apply

Whatever weeds you’ve had problems with in the past, will recur if not treated. That’s why identifying the weed you need to control is only the starting point for keeping weeds out of Bermuda grass. 

Different products have different chemicals. The labels tell you what’s in the bottle and what they help control. 

For example, the chemical Prodiamine works to kill crabgrass. Dithipopyr is effective against broadleaf weeds and grass weeds. 

Chemicals used in pre-emergent herbicides that kill Bermuda grass are: oryzalin, trifluralin, and pendimethalin. Don’t use those! 

The vast majority of pre-emergent herbicides are selective by their nature, because they’re applied to prevent weeds outcompeting what you’re trying to grow. 

To stay on the safe side, make sure to read the label to see that it is a selective herbicide. A non-selective herbicide (RoundUp-style) kills everything. 


Which type to use: Granular or liquid herbicide? 

This comes down to personal preference or the tools you have available. If you have a broadcast spreader, you’ll find it easier to get an even spread with granular herbicides. 

Liquid herbicides need a tank sprayer to cover the whole grass area. Both types need to be watered into the soil.


How much pre-emergent do I need?  

Liquid pre-emergent herbicides need mixed with water, then watered into the soil. Usually to a depth of at least half an inch. 

Expect between one and two gallons of pre-emergent liquid herbicide to cover up to 1,000 square feet. If you’re using granular herbicides, water the soil to a depth of at least a half-inch.

Again, the labels on the bottles tell you how much coverage you’ll get from each product and how best to apply it.

As an example, a 1-gallon bottle of liquid herbicide would state on the label that it “covers up to 25,000 sq ft”. To get that coverage, you need to follow the manufacturer’s instructions on how to mix it. 

Pre-emergent herbicides need to be applied over the whole lawn, but they do not kill weeds. They prevent weed seeds from germinating. 

However, since weeds remain dormant, technically, the germination phase is only being suppressed. That’s why you’ll forever be treating your lawn with herbicides. 

Despite using a pre-emergent, there are some tough weeds that are extremely resilient that’ll still manage to germinate. 

For those tougher to kill weeds, you’ll need a post-emergent herbicide. 

Tough weeds to kill are perennial weeds such as dallis grass, ivy, and clover. These types of weeds are the ones that make you feel like you missed a bit of lawn with your pre-emergent. 

Some weeds are just a little tougher to control. 


Post-emergent weed treatment 

A post-emergent herbicide can be applied over your entire lawn, or you could use spot treatment to spray directly onto weeds that’s managed to sprout. 

For treating your whole lawn, a post-emergent herbicide containing Quinclorac, 2,4-D, and Dicamba kills all weed types, except actual grasses so it won’t affect your Bermuda grass. 


The Ultimate Way to Keep Weeds Out of Bermuda Grass is Precise Lawn Care

Bermuda grass is a ferocious grower. Use that to your advantage because this will outcompete the vast majority of weeds. 

Master the lawn care basics for Bermuda grass to thrive so it has the strength to grow thick sprigs that’s long enough to shade weed seeds, preventing them from growing if they do manage to germinate. 

Pre-emergent herbicides suppress the germination phase, but it’s not 100% effective on every weed type. Some will get through, but Bermuda is just as invasive and can easily outcompete young weeds.  

The ideal length to keep Bermuda grass is between 1-inch and 2-inches. The only exception to that is the first cut of the year in early spring, just when the grass greens up. 

For the first cut of the season, take the grass back to a half-inch in length, essentially scalping your lawn as soon as it starts to green up. If there are any patches of thatch, remove that too to give the grass a healthy start to the year. 

After that, mow the grass regularly at a medium to high height level. If you’re noticing weeds start to come through, let the grass grow a little longer. 

The longer and thicker the grass blades are, the more nutrients they’ll use from the soil. 

Healthy soil keeps Bermuda grass strong enough to fight weeds itself.

Frequently Asked Questions related to keeping weeds out of Bermuda grass


What soil pH does Bermuda grass need? 

Bermuda grass needs a soil pH between 6.0 and 6.5. The richer the soil nutrients, the stronger the grass will be, which ultimately helps it to suppress weeds on its own. A pH lower than 5.8 weakens the grass making it easier for weeds to grow. Bermuda grass needs monthly fertilizing from spring.


How much water does Bermuda grass need? 

Bermuda grass only needs a half-inch to a quarter-inch of water every 1 to 3 weeks depending on the temperature. If you use a lawn sprinkler, those tend to water to a one-inch depth per half hour. Saturated soil encourages weeds. Bermuda grass needs very little watering.


What are surfactants and do I need it? 

Surfactants help liquids stick to plant tissue rather than rolling off it. It gets mixed with a selective herbicide. It’s useless on its own. When mixed with an herbicide, it increases its effectiveness for treating weeds like crabgrass, bluegrass, bittercress, and clover. 

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