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.
Would you like to save this stuff?
We'll email you this post, so you can refer to it later.
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.
Petra
Hm, we always just pulled them out.
Karen
Petra - When they're growing out of sidewalk cracks you can't pull them out. ~ k!
Linda
This sounds like a much better method than the one my brother tried when he was living on an airforce base. He poured lighter fluid on them and set them on fire! The MP's came - he was almost charged with arson but somehow talked himself out of it. Good thing, they probably would have given him a dishonorable discharge. For killing weeds! Boiling water is MUCH better!
marilyn
they'll be back
Beckie
I read about this method but thought it was purely hokum.
thanks for the visual!
added bonus: looking a bit...erm..*odd* with the tea kettle in the front yard =) (my neighbor leaves much to be desired...maybe this'll make him finally stop trying to talk to me!)
~off to boil 50 gallons of water~
Beckie
as I was pouring boiling water onto my garden path I wondered how many others across the globe were just now doing the same thing =)
Janet
I did this last summer on my pave uni patio, but I added a bit of salt, worked
Wendy @HerBallistic Garden
But, I was having sooo much fun pulling them out! NOT! I'll try this...thanks Karen.
Susan
Salt also works!!
Diane
All this talk about cracks is not good for my dirty mind! Think boiling water will fix THAT problem? lol :P
Suzan
I buy a round container of salt with the pour spout. Pour directly on the weeds followed by a little spritz of water to keep it in place. Kills them every time. No mixing, nothing fancy but it works!
Court
Would this work with the massive amount of weeds trying to take over my flower beds, or am I taking a large chance of killing my good plants?
Karen
Court - If the weeds are in your flower beds you should be able to just pull them out. The boiling water is for weeds you can't pull out, like those that are growing in between cracks. ~ karen!
Gayla T
Just when I thought we were BFF you go and turn on me! First off it's the snide remarks about hippies. It would not be as offensive if you could just please call us Flower Children it would help a little bit. And when I see a field of dandelions I see a field of salad greens, spring tonics, bee food and gun muzzle decorations. As if the hippie remarks were not cutting enough you have to rub my nose in those beautiful brick cracks. Just as I was beginning to recover from the demise of my brick sidewalks, you have tramatized me all over again. And for what? A blog blatantly showing the waste of good food by cooking it in cracks and then putting the vinegar dressing on while still attached to the ground. What kind of cooking show has this turned into? I think you have fallen down the stairs one time too many. I think you really need some rest or something. This whole blog has gone to hell in a handbasket and I'm not sure you even realize that you are no longer the blogger here. Someone by the name of Liz and her side kick Kay are taking over. I just have a couple of questions for them. I'm sure you don't mind. Just pretend you are already in the rest home while they carry on for you. Ladies, I just discovered that the 5 ft tall plant growing in my fence line is poison ivy. How would you suggest getting that much hot water on it and how much vinegar will it take to make a salad out of it? If someone can get the snail mail addy for the place they have put Karen in, I'll be happy to over night some of the salad to her as I'm sure it will have amazing curative power. Just as a reminder that we have not forgotten her, you know? Maybe one of you closer to her there in Canada could drop by and get the chicken to go with it. She's been kind enough to feed them all this time they can now feed her. Her! You remember, old what's her name??? The one who just posted a tutorial on making salads and couldn't remember for sure if she had just written it. She thought it was about weed killer or some silly thing.
Ruth
Oh.my.word.... I'm dying over here! DWL!
JBess
Genius! I'll try it!
It's a good way to remove ant colonies too. We generally leave the ants alone unless they start attacking the house- once they are on my kitchen counters all desire to live harmoniously with the ants disappears and I find myself walking out to their nest with a pot of boiling water.
SK Farm Girl
I have two more great methods for grASS Crack. 1. Use a blow torch to "burn" the weed to death (that is if you have a blow torch). 2. Lee Valley has a wonderful little tool called a "Crack Weeder" and it's only $5.70! Both work great, but I like the idea of "boiling" the weeds to death and it appears to be a slow painfull death - Mwah, hah, hah!! Die weeds, die! Sorry, must be PMSing and on the dark side of the moon!
Lindsay
I have kind of have the opposite problem in my cracks. The violets I grew last year volunteered their seeds right in between all of my pavers. It kind of looks weird but I can't bring myself to murder pretty little flowers. I'm torn, but at least now I know how kill them if I decide to! Thanks Karen!
Shirley
Hi, Linds! I had the same thing happen this year, only with pansies. Serendipity! My walkway pavers look so charming that I'm thinking of by-passing the intermediate step (the planters) next year and just throwing the seeds out the front door. One caveat: if you're going to try this at home, be sure to cut the package open first.
nancy
If they are real violets, and not violas or pansies, kill them NOW! Spray each little leaf with Roundup or other expensive killer or you will be very sorry, they can be VERY invasive.
Linda Thomas
Amen!
Dixie Lee
PLEASE read about round up. Think about what we are leaving for our children to have to clean up. They may not have kids of their own if we keep this up.AND Roundup has something like a 200 year half life
Liz S.
Kitt- Thanks for tip. I need to kill weeds and grass along my fence and side if house so I don't have to drag the trimmer out everytime I mow. Looked at the super killer stuff in stores but it's a good $15 to $25 and contains God knows what. Really don't want to spray that in the same yard my 2 year old plays in.
Karen
Liz S. - Kay. Um. I gave a weed killing tip too. Ya know? The one with the boiling water. Where you pour boiling water on a weed. I wrote a post about it at some point. Recently as far as I remember. ~ karen
sara
Maybe you should post the link?
Charlene Austin
Too funny!!!
Langela
Yes, Karen, post a link. You always have such good ideas and we love your humor. We'd love to hear what you've tried.
Karen
If I'd wanted this kind of abuse, I'd have become a mother. ~ karen
Nicola Cunha
Mommy, there are weeds under the swing!!!
Ha, ha, Nicola :)
Liz S.
But it's difficult to run around a big fenced in back yard (inside and outside of fence plus perimeter of yard and sidewalks) with a tea pot of boiling water and 2 year old in tow. The boiling water will be great for weeds trying to poke up through my mom's wood deck but can't be easily reached.
Leona
Just have the 2 year old carry the pot and you can kick back with a glass of wine, right?
(I'm obviously not a mom but I just can't resist reaching out to help others.)
;)
Bonnie
I recently tried boiling water with household vinegar...it instantly cooked the greens, but they'll need a couple more treatments to kill the roots. I also tried boiling pasta water...so far so good :)
Kitt
I have been using a mixture of household vinegar (1 gallon), salt (1 cup) and dishwashing liquid (1 squirt) in a garden sprayer to kill the grass and weeds between my patio flagstones and it's quite effective.
Karen
Too much mixing for me. I hate mixing ingredients up unless it's going to result in food. But thanks for letting us know. I'm sure there are others reading the comments that don't have such a mixing aversion, LOL. ~ karen!
Shannon V.
Karen...this is the recipe that I use as well (along with the boiling water method) but when I mix it, I put it into a gallon size garden sprayer (or bigger if I have it). That way it is less mixing and easier on you hands then a trigger sprayer. I either use household or pickling vinegar.
Gail
Karen -
LOL! I'm with you. Even if it results in food .... if there are too many ingredients listed .... not happening! Run into an ingredient going down the list I don't like .... not happening!
Even though my husband helped me pull the weeds against the brick, I'm going to try the boiling water now. Happy weeding to you!
Slim Paley
Genius.
Katie
Awesome! There is another method that works well and definitely kills the crack weeds - mixture of water and household vinegar!
Karen
Katie - Have you tried this and had it work? I know that horticultural vinegar (which is much stronger) works, but always heard that regular household vinegar isn't strong enough. ~ karen
Katie
Yes, Karen, I have tried it. It does work! I used household vinegar with 5% acid. I don't know if you know this, but those vinegar is a mild form of muratic acid! I also use them to lighten up my bathroom floor grouts (they are 50 year old grouts).
Sherry (BTLover2)
And we recently used white vinegar straight from the bottle on our cracks. I was skeptical too but it actually worked. The only thing I will say is that we did not have dandelions. We had some type of weed that looked like grass (wimpy grass). I'm not sure how well it would word on the tough guys. Your boiling water method sounds even better (more time consuming but cheaper) ;)
Sue
Straight household vinegar works for me, too. It works *best* on really hot sunny days, though. Not sure if it's the sun effect on the vinegar soaked plant, or if the heat causes the roots to suck up moisture faster, or maybe a bit of both.
bob jinglhimer Shmitt
Pure 5% acid white vinegar will do the same thing as Round up. It kills everything. Becareful. Use in between pavers and cracks in cement and driveways.. Don't use in garden as if it gets on any leaf it kills it. Yes Even Poison Ivy. It is water soluble so use it on hot sunny days to work mot effective. It won't leech int soil like Round up says it wont.. But Vinegar is 2 dollars a gallon. Round Up is 25-30 dollars a gallon. Plus Round up is made by Monsanto..The same CORP that told the Vietnam Vets it was perfectly safe to use AGENT ORANGE... Use vinegar.
Claudine
Good job. Mother Nature still loves you...