Northern Shade Gardening

Killing Weeds with Hot Water

Saturday, July 18, 2009 Category: General

Here is an easy method for getting rid of weeds in sidewalk cracks and between patio stones. I’ve found it to be very effective, and it’s completely non-toxic. I use boiling hot water for killing weeds in the gaps, and have found it to be very successful at removing just about all of the weeds. You can see in the pictures below how well it works.

I carry the boiling water into a coffee carafe with a lid and pour spout for safety. It wouldn’t be a safe idea to be moving open pots of boiling water. I wear enclosed boots for safety. I also make sure to pour it down low and away from myself, so it doesn’t splash up, while killing the weeds.

I just pour the boiling water on the weeds in the cracks, and most look like cooked vegetables a few hours later. Most weeds are dead the next day. I’ve found a few established weeds might need a second treatment, if they haven’t died in a few days.

I usually use this method of killing weeds in early summer, but it’s a little later this summer, so some of the weeds got a little big before the boiling water treatment. Within a few days, the weeds have usually crumpled into tiny dessicated pieces that disappear. A week or so later, you hardly see anything left.

Here are some before and after shots of the weeds that were killed in my sidewalk and driveway. The old weed on the top half, and the dead weed on the bottom half. I should have set up little signs, as after a day it was much harder to recognize individual weeds.

weeds before and after boiling water

weeds before and after boiling water

Here is a before and after photo of the weed killing in action. The bottom of the picture was taken 4 hours after the boiling water was applied. You can see how quickly this one died.

weeds before and after boiling water 3

weeds before and after boiling water 3

The bottom half shows the pineapple weed the day after applying the boiling water to kill the weed. This might not be the exact same pineapple weed as I had trouble matching up the dessicated leaves. Within a day they are dried up and breaking down after the boiling water kills them.

weeds before and after boiling water 2

weeds before and after boiling water 2

This shows another weed, knotweed, before and 2 days later, now dead after the boiling water application.

I usually apply the boiling water once in early summer, and that’s all that’s needed for the season. It’s highly effective at killing weeds. I don’t know if those with a longer growing season might need to do it more than once. I’ve been using the boiling water method for 3 years and have been very pleased with the results.

What I like about this method of killing weeds is that it is completely safe for the environment, your family and animals, with no toxic lingering effects. It is perfectly safe for pedestrians and pets walking down the sidewalk in front of my house. Using boiling water is the fastest, easiest and most non-toxic method for weed killing between patio stones, driveway sections and sidewalk blocks.

37 Responses to “Killing Weeds with Hot Water” »

  1. Helen at Toronto Gardens :
    July 18, 2009 at 12:40 pm

    Great tip; quick and simple.

  2. Joanne :
    July 18, 2009 at 12:45 pm

    Thanks for reminding me I really must use this on some of my paths.

  3. Northern Shade :
    July 18, 2009 at 1:21 pm

    Helen, it’s very effective and much easier on the fingers than hand pulling against the cement. I don’t mind hand pulling weeds in the soft soil of the garden beds, but my fingers used to get scratched up from pulling the weeds out from between the gaps in the cement. It used to take me hours to pull them from all of the walkways and paths.

    Joanne, when I use boiling water on the walkway cracks next to the garden, I hold a barrier at the end of the crack, so the water doesn’t run into the garden bed.

  4. Rebecca :
    July 18, 2009 at 7:49 pm

    Wonderful idea!! And great pictures to prove it works. Do you remove the dead plants, or do they go away on their own?

  5. Northern Shade :
    July 18, 2009 at 8:44 pm

    Rebecca, they mostly dessicate, shrivel into tiny pieces, and are gone within a week. That makes it especially easy. A couple of extra large dead weeds might have to be removed later if they haven’t disintegrated.

  6. Joy :
    July 19, 2009 at 5:20 am

    I have heard of this one before but I’m so glad you wrote about it .. apparently it got stuck in my “vault” and I forgot until I read this and said “Oh yeah !!” haha
    We don’t use any chemicals here now … I do a lot of manual labor on weeds and some how digging them up is a great stress buster .. go figure ? haha
    Great post girl !
    Joy

  7. Northern Shade :
    July 19, 2009 at 6:58 am

    Joy, I like hand weeding in the garden beds too. It does have a certain satisfaction, and if you start early, have your plants fairly close, or use mulch, it doesn’t get too bad.

    I really disliked hand weeding from between the cement spaces of the walkways, driveway and front sidewalk, though. It would take me so many hours, and my finger tips would get scraped raw against the cement. The boiling water is so much faster and easier.

  8. obrien :
    July 19, 2009 at 2:47 pm

    i have a weed that is like a vine and wraps itself aroung my fence or other garden plants and flowers, any suggestions

  9. Northern Shade :
    July 19, 2009 at 6:19 pm

    Obrien, weeds can be very frustrating when they have become established like your vine. I’ve only ever used the boiling water method on the weeds in my sidewalk gaps. I hand pull the weeds in my garden beds, but if you have a weed with long runners or roots, it takes a lot of persistence. I don’t like to use chemical weed killers, since so many of them have negative health effects on people and animals.

  10. easygardener :
    July 20, 2009 at 2:59 am

    I’ve being walking past some dandelions in my front paving for the last few weeks muttering that I must dig them out…and then forgetting. I’ve just boiled some water so I’m off to test your method!

  11. Northern Shade :
    July 20, 2009 at 7:44 am

    Easygardener, I’ve found the boiling water so much faster and easier than trying to dig them out of the cracks, especially if you have a lot of paving gaps. I have almost no new weeds grow afterwards.

  12. Becky :
    July 20, 2009 at 9:04 am

    Every time I try to weed the cracks between the stones, ants bite my ankles. My teakettle is going to become a lethal weapon. I’m thinking a little ant soup to go with weed tea will hit the spot. Thanks for the HOT idea!

  13. Northern Shade :
    July 20, 2009 at 9:56 am

    Becky, for such a simple method, the boiling water does a surprisingly good job of killing the weeds, and returning them to dust.

  14. Garden Gnome Wanderings :
    July 20, 2009 at 10:54 am

    Excellent advice! Killing weeds with boiling water is ever so simple yet effective. It is one of the methods I’ve tooted for years but is now getting a bit more attention with Ontario’s new pesticide ban. I love how you used the before and after pictures to illustrate how effective this method is.

  15. Northern Shade :
    July 20, 2009 at 11:29 am

    Garden Gnome Wanderings, good for Ontario for banning pesticides and herbicides for cosmetic reasons. I’m sure that 10 or 20 years from now, people will look back in disbelief that homeowners actually used to poison their own property for such minor reasons.

    Thanks for adding my blog as a favourite.

  16. Gail :
    July 20, 2009 at 5:29 pm

    This is the perfect solution for the cracks in my driveway! I do have to remind my plant sitter to let the hot water clear out of the hose before watering or the plants would die. gail

  17. Plant Lady :
    July 20, 2009 at 5:37 pm

    What a fabulous idea! I am definitely going to try this if anything comes up in the new veggie garden’s paths.

  18. Northern Shade :
    July 20, 2009 at 9:00 pm

    Gail, I have a grid of expansion gaps in my driveway, and this works very well to kill the line of weeds. I used to have trouble getting my fingers into the little gaps to get a good hold on the weeds. This is so much easier.

    Plant Lady, when I use the boiling water on the spaces in the walkway near my garden bed, I put a barrier at the end of the gap so the water doesn’t accidentally flow onto the garden.

  19. Linda :
    July 21, 2009 at 4:52 pm

    I’ve not heard of this method & as soon as I’m done typing will go boil water! I have a few graveled paths I put off weeding until it’s so too late! Then the snow flies & I pretend I don’t have to deal with it until the next year. Thanks!!

  20. Northern Shade :
    July 21, 2009 at 5:50 pm

    Linda, your fingers will be a lot less sore weeding those graveled paths with the boiling water, and it should take a lot less time too.

  21. Jackie :
    July 21, 2009 at 8:43 pm

    Nice blog! Thanks for posting this valuable info. I’d heard about the boiling water treatment, but never seen proof before. Thanks so much! -Jackie

  22. Northern Shade :
    July 21, 2009 at 9:17 pm

    Jackie, it doesn’t take long for most weeds to start appearing dried and dessicated. Most look dead in the first few hours. A couple of days later there are just pieces of withered leaves, and in a week, they will have mostly disappeared.

  23. Rebecca :
    July 22, 2009 at 12:40 am

    Since we’re on the topic of getting rid of unwanted ‘pests’, have you had any problems with slugs? I a few plants in my shady/moist areas are getting chomped. I bought some Safer’s Slug Bait, but have since read about using coffee. Just wondering if you have any experience with either? :)

  24. Northern Shade :
    July 22, 2009 at 7:07 am

    Rebecca, I haven’t really had many slugs yet, so I don’t have experience with anything other than hand removing the occasional one.

  25. Frugilegus :
    July 22, 2009 at 4:44 pm

    I love the before and after shots – fabulous.

  26. Northern Shade :
    July 22, 2009 at 9:21 pm

    Frugilegus, it’s very satisfying when they all look like the after photos (although I have to grudgingly admire plants that are willing to put up with the conditions in a sidewalk crack in order to grow).

  27. Belga :
    July 28, 2009 at 7:40 am

    What a fantastic tip. I have tried it today, and it really works. I have quite a big gravel driveway, and I’ve been struggling to control the weeds, so this has been a revelation to me! There is also an excellent side effect – the boiling water makes the soil underneath wet AND warm, so some taller weeds, and grass, can be pulled up more or less straight away by the roots. Great for me as I am too impatient to wait even one day!

  28. Northern Shade :
    July 28, 2009 at 9:26 am

    Belga, I’m glad it made it easier to get rid of the weeds in your gravel driveway, and there are no toxic after effects. It seems to kill the seeds on the top too, so I don’t usually have new weeds appearing in that season.

  29. Barbara :
    August 22, 2009 at 12:56 am

    Oh, I certainly will have a go with this friendly method! I really wonder whether it will function on my garden terrace too!

  30. Northern Shade :
    August 22, 2009 at 7:58 am

    Barbara, I use boiling water to kill the weeds between my patio stones, and it works very well. This non-toxic method is safe, and it’s reassuring to know that you’re not poisoning your land or the animals.

  31. Erik :
    February 2, 2010 at 8:20 am

    Excellent tip. The photo’s say it all. Just wanted to share that a Canadian company (ours -yes, shameless plug) is shipping steam weeders big enough to enable city workers, schools, etc. to do the same thing on the miles of cracks they are responsible for. And in terms of what we can all do to help, whenever we see someone spraying sidewalks with a chemical back pack at 6 a.m. (to avoid your prying eyes and wind drift) we can can do more than grumble, we can suggest they Google ‘steam weeding’ or ‘killing weeds with hot water’. Thx for a great post.

  32. Valerie :
    April 25, 2010 at 10:40 am

    Will this method of boiling water work for dandelions on the lawn or will the boiling water kill the grass?

  33. Northern Shade :
    April 25, 2010 at 11:20 am

    Valerie, I haven’t used it on the lawn, as I think it would damage the grass. However, it does an excellent job killing the weeds in the gaps of sidewalks, patios and driveways.

  34. Bob :
    May 5, 2010 at 10:51 pm

    Hi thanks for the idea, but i was just wondering is it harmful to the plants close the weeds, the plants that you want to kerp

  35. Northern Shade :
    May 5, 2010 at 11:20 pm

    Bob, I primarily use this method on weeds in the cracks of the patio or sidewalk blocks, so there are no adjacent plants. I also place a large piece of cardboard at the end of the gap, if it is close to the garden bed.

  36. Jason :
    May 27, 2010 at 9:56 am

    Great tip! I’m glad to see how well they worked with the pineapple weed. I’m having a problem with them this season and even the toxic herbicides don’t seem to work (they are especially waxy plants…) Thanks, will definitely try!

  37. Northern Shade :
    May 27, 2010 at 6:46 pm

    Jason, there’s a fairly quick response to the boiling water, with rapid dessication.

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