Bleach does more than whiten clothes—its potency also kills pesky weeds. It is the perfect homemade solution for getting rid of isolated weeds, like those growing in between pavers or on a patio.
Learn why bleach is effective at killing weeds, how to mix up a solution for spraying, and what precautions to take to do the job safely.
As a gardener, I’m constantly battling weeds in my yard and garden. No matter how much time I spend painstakingly pulling them by hand, they always seem to grow back quickly When I get frustrated with weeding, using chemicals like bleach to kill weeds seems appealing But does bleach actually work to kill weeds all the way down to the roots so they won’t regrow? I decided to dig into the science and find out.
How Bleach Works On Weeds
Bleach contains sodium hypochlorite which is extremely alkaline with a high pH. When bleach makes contact with plants, it interferes with the weed’s ability to absorb minerals and nutrients through its root system. The sodium in bleach damages the root tissues effectively suffocating the plant.
Bleach also dramatically raises the pH of the surrounding soil when applied directly. Most plants require a fairly neutral pH to thrive, so this change in soil chemistry after using bleach can inhibit weeds from regrowing.
Evaluating the Effectiveness of Bleach on Weed Roots
For small annual weeds just starting to establish, bleach can be very effective at killing the root system and preventing regrowth when applied liberally and directly to the leaves and surrounding soil. However, for larger established perennial weeds with deeper, more extensive root structures, results are less consistent.
According to gardening expert Craig Wilson, bleach does not always succeed at killing bigger weed roots:
“Although bleach can be applied directly onto weeds using a spray bottle, it’s not always guaranteed to kill the root system, meaning the weeds can grow back.”
So while bleach may initially damage the above-ground foliage and some of the roots of larger weeds, new growth can still emerge if the root system isn’t completely destroyed.
Factors That Impact Weed Control With Bleach
There are a few key factors that determine how effective bleach will be at killing weed roots and preventing regrowth:
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Weed Size and Type: Small, young annual weeds with shallow roots are much easier to control with bleach than large, established perennial weeds. Taproots are harder to fully kill.
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Bleach Concentration: Using full-strength bleach will do more root damage than dilute solutions. But this comes with some environmental tradeoffs.
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Amount Applied: More concentrated bleach in one area does more harm to roots. But too much can sterilize soil long-term.
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Repeat Applications: Multiple bleach treatments increase root kill rates. But this greatly raises the risks of soil contamination.
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Soil Moisture: Dry soil limits how quickly the bleach can penetrate root zones, reducing effectiveness.
Getting complete root kill with bleach requires finding the right balance. You need enough bleach to damage roots, but not so much that the soil is ruined.
The Downsides of Using Bleach as a Weed Killer
While bleach can potentially kill weed roots, it has some big drawbacks that make other options usually better:
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Bleach is non-selective and will damage any plants it contacts.
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It leaves toxic residues that remain in soil for a long time.
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It can contaminate groundwater if it seeps down past the root zone.
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It may take heavy, repeated applications to fully kill deep roots.
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It can stain porous surfaces like concrete or wood if not rinsed off.
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The fumes are unpleasant and require caution to avoid irritation.
Safer Alternatives to Kill Weeds Down to the Roots
Given the risks, most gardeners are better off using less toxic methods to eliminate weeds:
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Manual weeding works with some persistence to pull weeds out entirely.
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Soil solarization uses heat under plastic to kill roots over several weeks.
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Natural herbicides like vinegar, salt and boiling water can be effective.
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Landscape fabric blocks sunlight and smothers growth over time.
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Maintaining thick, healthy lawns prevents weeds from establishing.
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Corn gluten or synthetic pre-emergents provide residual control.
While bleach seems like a quick fix, the risks usually outweigh the rewards. Investing in less toxic weed control methods is better for your yard’s long-term health. With some persistence, you can eliminate weeds without nuking your soil with bleach.
Why Bleach Works to Kill Weeds
Bleach is an effective weed killer against most types of small weeds. It works at the root level, where the sodium content of the bleach interferes with a weeds ability to absorb minerals.
When applied undiluted, bleach often even prevents weeds from coming back for a long time because it raises the soil pH to a level unsuitable for many plants.
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How to Use Bleach on Weeds
Weed control is part of sound patio landscaping, and this includes killing weeds that grow up between pavers that have been set in sand (without mortar). This is just the sort of area where bleach can be used as a weed killer.
With your spray bottle, spray the area where the weeds are coming up. Dont be too quick to pull the weeds out afterward—wait a few days to make sure theyre dead.
Besides targeting weeds between patio pavers, other suitable uses for a bleach herbicide include killing weeds in sidewalk cracks, along the edge of the driveway, or between flagstones in a sand-set stone path.
Does Killing Weeds With Bleach Also Kill the Roots?
FAQ
Will bleach kill weeds permanently?
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How it works:Bleach, particularly chlorine bleach, is toxic to living organisms, including weeds. When sprayed on weeds, the liquid soaks into the soil, killing the plant, roots, and all.
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Effectiveness:Bleach is effective at killing mature weeds and can prevent new weeds from growing because it remains in the soil and makes it infertile.
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Precautions:
- Non-selective: Bleach is non-selective, meaning it will kill not only weeds but also other plants and grass.
- Soil toxicity: Bleach can make the soil infertile for years, so it’s best to avoid using it in areas where you want to grow plants.
- Harmful to pets and children: Bleach is harmful to pets and children, so it’s important to keep it out of their reach and to avoid using it in areas where they might come into contact with it.
- Dilution: You can dilute bleach with water, but it’s still toxic and should be used with caution.
- Non-selective: Bleach is non-selective, meaning it will kill not only weeds but also other plants and grass.
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Alternatives:There are other methods for killing weeds that are less harmful to the environment and pets, such as using vinegar, boiling water, corn gluten meal, or mulching.
How do you kill deep rooted weeds?
Grab an herbicide.
Plant-killing chemicals, or herbicides, are one of the best weapons against brushy weeds, because they can kill leaves, stems and roots when applied properly. They’re especially helpful when you’re faced with a large weedy area.
What is the ratio of bleach to water to kill weeds?
Use the right kind of bleach: Be sure you’re using chlorine bleach—this type of bleach is best for killing weeds. Mix with water: Bleach is strong enough that you can dilute it to kill weeds. Stretch your bleach supply by mixing it with water: 1 part bleach to 5 parts water does the trick.
Does bleach damage soil?
Bleach is harmful to the soil as it contains chlorine and other chemicals that can alter the pH balance and kill beneficial microorganisms.Jan 24, 2024
Does bleach kill weeds?
Bleach will kill weeds because it’s toxic to all living things. It’s formulated to kill germs and algae, so it has no problem killing your pesky dandelions, crabgrass, and bindweed. If you spray diluted bleach on a weed, the liquid will soak into the soil and kill the plant, roots and all. Here’s the problem, though.
Does Clorox bleach kill weeds?
Clorox bleach can kill weeds permanently. It is safer to spot-treat weeds with bleach because it is a nonselective DIY herbicide. If you’re using a garden sprayer, aim carefully and apply only on undesired plants. Alternatively, you can use selective herbicides to prevent damage to ground-cover vegetation in your yard.
Does bleach kill plants?
When bleach soaks into the soil, it makes its way down and kills the plant from the roots upward. Here’s the kicker, though. Because the pH level of bleach is so high, it makes the soil very alkaline.
How do you use bleach to kill weeds & grass?
Here’s how to use bleach to kill weeds and grass: Pour undiluted bleach into a garden spray pump. Spray the bleach directly onto the weeds in your yard, between pavers and driveways. Repeat the application after 2-3 days on weeds and grass that did not die. Pull out the dead weeds to keep the yard clean.
How does chlorine bleach affect plants and weeds?
Chlorine bleach affects plants’ and weeds’ growth in two ways. First, the sodium content overworks the plant’s system with salts. While chlorine is a necessary part of the soil, too much can cause a condition called chlorine toxicity. Also, concentrated bleach has a pH of 11, which increases the soil’s pH crucially.
Can weed spray kill weeds?
To use the weed spray, fill it with water and add bleach. Then attach it to your garden hose and turn on the water. When spraying, keep the nozzle as far away from plants as possible to avoid accidentally spraying them. This will prevent damage to your plants while using bleach to kill weeds.