You’ve probably heard that boiling water kills weeds. It’s one of those tips that floats around—usually mentioned right after vinegar and just before something involving Dawn dish soap.
But does it actually work?
Sort of. On some weeds. In certain places. If you do it right. It won’t touch anything with a deep taproot unless you’re committed to repeat treatments. But for weeds growing in sidewalk cracks or between bricks, it works. Not instantly. Not perfectly. But it works!
This is what happens when you use it—and what to expect if you do.
Table of Contents
Does boiling water kill weeds—yes or no?
Yup. It does. Sort of.
If you pour boiling water on a weed, the leaves collapse like they’ve been caught rolling their eyes in church. They go limp. They shrink to half their size. They eventually go brown and die.
But then? Sometimes they grow back.
Why? Because weeds are petty little things with deep, vengeful roots. Especially the ones with taproots—like dandelions, dock, and plantain. You might have to hit them many times before they finally give up and move on to the great sidewalk crack in the sky.
Pro tip to remember: Use a kettle, not a pot. Kettles are precise. Pots are boiling water wave parks.
How boiling water actually affects weeds
Instant effects on foliage
The moment that scalding water hits the leaves, it's like flipping a switch. The plant cells rupture from the heat.
It’s deeply satisfying. Visually. Emotionally. Spiritually, even.
Impact on roots
Under the surface? Not as dramatic.
Boiling water can damage the crown or top of the taproot if you saturate it enough. But unless you pour a lot, or do it more than once, the deeper root stays alive. It’s just down there. Plotting its comeback.
Weeds with shallow roots though? This works great on them.
Why some weeds bounce back
Taprooted weeds store energy. The moment the top gets damaged, the root kicks into emergency mode. New leaves. New shoots. Like nothing ever happened.
But even taproots only have so much energy. Eventually, if they can’t recharge with new leaves, they die.
The Trick
If you want to kill something like a dandelion with boiling water, here’s how:
Repeat the boiling water treatment 5 or 6 times. Every time you see even a tiny bit of green, pour more boiling water on it. It’s annoying. But it works. Eventually, the root runs out of energy and dies.
When boiling water works best
1 hour later
2 days later
Good Uses :
- Sidewalk cracks
- Between patio stones
- Gravel driveways
- Dry, compacted areas where nothing else grows anyway
These weeds usually don’t have deep roots. One or two treatments and you’re good.
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Terrible Uses:
- Grass – You’ll have dead spots everywhere.
- Garden beds – Risky. Boiling water doesn't discriminate. It’ll kill your kale as fast as your chickweed. Not that anyone’s mourning the kale.
- Dandelions in your lawn – Unless you’re into polka-dotted grass, maybe don’t.
How to use boiling water safely
What you need
- Electric or stovetop kettle
- Long sleeves (trust me)
- Closed shoes (not flip flops, not barefoot, not once, not never)
- A killer instinct
Don’t use a giant pot unless you want to slosh boiling water down your legs. I don’t recommend that. Kettle. Always a kettle.
How much to use & how often
Pour slowly and directly over the weed’s crown. Soak it. Let it sizzle a bit. Walk away. It'll be brown soon.
Come back in a week. If it’s looking perky again, repeat.
Usually takes 2–5 rounds, spaced about a week apart, depending on the type of weed and root. You’re basically wearing the weed down until it taps out.
Avoid splash damage
Be careful near garden beds or anything you don’t want dead. The heat spreads underground a little and can fry the roots of nearby plants.
Aim carefully and pour slowly.
The Results
- 1 hour later – Wilted, floppy, green leaves
- 2 days later – Crispy brown death
- Larger weeds – May need more treatments
- Deep roots – Still alive, but not happy
Pros and cons
The good:
- No chemicals. No danger. No birds growing beaks out of their bellybuttons.
- You’ll see wilting in minutes. Yay!
- You have everything at home to do it right now.
The annoying:
- Doesn’t always kill the root
- Needs repeating
- Kills everything it touches
- A lot of kettle refills if you’re dealing with a big area
What nobody tells you
Seal the cracks
Once the weeds are genuinely dead, sweep up the corpses and fill the gaps with sand or polymeric filler. Otherwise, the cracks are just open invitations for the next round.
Lots of weeds = lots of water
If you're treating a long driveway or entire patio, boiling water gets old fast. Waiting for kettles to boil over and over again is—how do I put this—painfully boring.
Got a big job?
Rent a proper weed steamer. Yes, there is too such a thing. It’ll cover a bigger area much faster.
Anyway. That’s how I spent an afternoon boiling weeds to death.
Kristen S
Hey Karen, you got any mother nature tips to keep bugs out of your vegetable garden? Those douchey little aphids are eating my peppers. Been squirting them with water and dish soap, but I just cant seem to get rid of them.
Karen
Kristen - I hate aphids. I hate them I hate them I hate them. I usually suck it up and go out and squish them with my fingers. Which is disturbingly gross. I've used the "Green Earth" brand of insecticidal soap to great success with white flies and to some success with aphids. Stupid aphids. I hate them. ~ karen
Beckie
plant marigolds! the old-fashioned, heavily scented type
those marigolds keep a lot of nibbly buggies at bay
Kristen S
Damn...squishing eh? I don't know why but those damn little things freak me right out. Especially the pink ones. I was hoping you'd have a magic aphid murdering tea, or some form of aphid voodoo doll. My skin crawls just thinking about those little bastards.
Jan
How about unleashing a container or 2 of ladybugs? Apparentloy they LIVE to devour aphids.
Jan
"apparently"
Katrina
*BOOOOOM!!* <--- my mind being blown
Dawna Jones
Good job Karen I knew that but I have a husband who dresses up in a villian suit at night and then goes around spraying everything with poison laughing hideously like the joker. So this will fall on deaf ears.
dawnajonesdesign.com
PS your blog is the best.
Karen
Thanks Dawna. :) ~ k!
Maureen
Also, FYI...I tried to post a link to this post on my FB page and couldn't. Got a message that this post has been blocked for "spammy content." I reported it to FB to say that you are legit. I wonder if others are also having this problem.
Karen
Weird. Thanks for reporting it! ~ karen
Brandi
Figures that this is your post today when I pulled weeds for 2 hours yesterday! Thanks for the tip though, definitely going to try this on my crack!
Maureen
Karen, you are just super-duper. Thank you for everything. And just tell those judgemental neighbors to f-off.
Patti
Great post, Karen! My neighbour kept telling me that boiling water is the best way to kill weeds, and, though I`m sure this was a hint from her (my patio is all stone and the weeds have made themselves a lovely home there), and though her patio is completely free of weeds, I kinda needed to see it to believe it - and now I have! So I guess I know what I`ll be up to tonight!
Thanks for your informative posts!
kate
wow! thanks for the boiling water tip! I'll try it today...weee
Sherri
I've got enough weeds on my acre to try all of these methods and see which one works the best. Thanks for the tips, Karen and fellow fans!
Shannon V.
Karen....any tips on getting rid of creeping charlie that has started to take over the lawn...aside from ripping everything up and starting over.
Thanks
Shannon
Deb J.
I tried the boiling water thing with very temporary results. Maybe I wasn't persistent enough. And I found it hard to have enough boiling water - had to take the kettle outside and keep plugging it in. Still have 'crack grass'. Tried the vinegar too. Same temporary result but not the boiling bit. I suspect I might be killing the weeds but new ones are blowing in. Bleh! Next thing to try is to treat the weeds and then apply a new layer of the sand you put in the cracks. Maybe this will prevent some reseeding. However I have one dandelion at the base of a wall like Karen shows that I suspect has a root to China! I cut it out, poison it, boil it, vinegar it and it keeps coming back bigger. Maybe we should all admire dandelions - they are pretty amazing:)
Barbie
I'm going to try this Karen at least in my cracks on the sidewalk. Great idea! My Hubs will love this!
Jillian
A little bit of bleach mixed in after the water is boiled kills weeds and ants.
Lorna
This also works well on ant nests. We had a TON of ants last year making ant cracks (hmmm, doesn't sound as interesting as grass crack for some reason), and didn't want to use poison on them so I boiled them with a kettle or two of water. I had to do it a couple of times last summer since the survivors out hunting in the boonies came back and started new nests but it kept them down to a dull roar.
Ann
I have long used boiling water and love that it works so well and so fast. I am now adding some salt when I am working in an area that I don't want the weeds to ever come back. But you have to be careful using salt. It will act as a long term herbicide but it can leach out into areas you don't want to have it in. I use it down the middle of my gravel driveway but not at the edges and it seems to keep the worst of the weeds down.
Vinegar has been a dismal failure for me as a weed killer. Even the horticultural strength. Not worth the effort of spraying it.
Occasionally, and I do mean very seldom, I do use a glycosate product. Never, ever, ever do I use Roundup. Monsanto is the Devil's company in my mind and I will not use anything they make. But there are just some rare times and places I need to get quickly cleared of vegetation and it does do the job. I just spent a lot of money to buy an even more organic type weed killer on line and it was a dismal fail. I was hoping for a better alternative to glycosate but so far it is not to be.
Deborah
And if you have a problem with pesky ants, the boiling water trick works on them too! Although they don't turn red like lobsters though :P I have been using the Vinegar/Salt/Dishsoap "Herbicide" for the past few years, stuff works like magic - especially on MOSS. That darn stuff would not die no matter what you sprayed on it, I almost resorted to gasoline in my quest to rid my patio of moss. Then I discovered the all-natural herbicide of just 3 ingredients, and it really isn't THAT much mixing! Try it - you'll be amazed. Remember to thoroughly mix the salt and vinegar together before adding the dishsoap, otherwise, you end up with a spray bottle full of bubbles!
Kim from Milwaukee
Deborah, because of you I'm predicting Karen will next post a recipe for salt and vinegar chips (sans dishsoap). I thank you!!!
Deborah
I am sure she will :) Here is my herbicide recipe that I use if you (or anyone else) is interested...
http://www.thehomesteadingrealtor.com/the-homesteading-gardener/weeding-through-life/
cred
I tried planting irish moss between our paving stones but the weeds sprouted up before the moss could grow dense and out compete the weeds.
I gave up and tried digging up a portion and replaced it with gravel. Before I was finished with the whole area, weeds started growing up in the gravel. So, I'd abandoned ship and left the walk half finished.
But now I have hope, I am going to try this on the gravel- thanks for the idea.
Lynne Knowlton
Seriously ? I have been staring and hating my weeds for all these years for nothing?!
Gotta run...I'm off to make a cup of tea and boil the heck outta some bad a$$ weeds.
You d'best, you d'best, you d'best... Pretend I sung that in a beautiful rainbow voice.
Lynne
Goodbye evil weeds.
Selva
This seems cruel ... I think it's better to kill them suddenly pulling them to avoid the suffering of dying slowly :-/
Lisa
Hi Karen-
I have a cool thing I call my miniature flame thrower. It's in the shape of a candy cane and powered by a small propane tank. I turn on the gas and light it up by clicking a button - kinda like lighting a gas grill. In no time weeds are burned and their roots are destroyed with a couple passes of the flame. It's fast and easy. Just dont wear flip flops while doing this in case you need to stomp anything out. Works like a charm.