Can you really kill weeds with boiling hot water?
The internet has been awash with all kinds of homemade weed killers recipes. Salt, vinegar, bleach, boiling hot water or a mixture of each have often been touted as cheaper, more environmentally friendly and more effective than commercial weed killers.
Let me tell you now, it's all a load of rubbish, old wives tales recycled for the modern age.
Boiling hot water will not kill most kinds of weed. It may kill small, young or weak weedlings but in most cases it will simply stun them, weakening them for a while but they will regrow.
How does boiling hot water affect weeds?
Looking for a natural or organic way to kill weeds on your driveway, paths or patio?
You've probably heard or read somewhere that boiling hot water can kill your weeds, it will damage most plants but kill them permanently? Probably not.
Scalding hot water from the kettle burns your weeds just like it would your hand.
For young, weak weeds this may just be enough to tip them over the edge and kill them. Deep rooted, long established weeds will simply be stunned but they will recover.
Is it safe to use boiling hot water on weeds?
Yes! Along with salt, boiling hot water is probably the safest method to try and kill weeds.
The only risk is burning yourself with the hot water.
It won't cause any damage to the environment but please ensure children, animals and insects are removed from the area when using the hot water - we don't want any accidents.
Should you use boiling hot water on your weeds?
There is no harm in trying!
How to use boiling hot water to kill weeds:
One of the reasons the myth of hot water working as a weed killer has stood the test of time is because it's easy, cheap (FREE!) and there is some truth in it, it does damage the weeds.
I shouldn't have to explain how to use boiling water as a weed killer but here goes...
Fill up your kettle, boil it then pour it directly over the weeds.
Yes! That's all there is to it.
Please note: Don't use boiling hot water to kill weeds in your lawn. It will kill your grass, use a proper lawn weed killer for lawn weeds. Don't use it to kill weeds in artificial lawns either - some types of fake grass are plastic based and the hot water could melt or deform it!
How effective is it?
We tested the boiling hot water method on a variety of small grassy weeds, we used 5 kettles full of boiling hot water to cover the whole area.
You can see the results for yourself in the images below.
How long does it take for boiling water to kill weeds?
It won't kill your weeds but you should start to see them wilt within 1-2 days, sometimes it will work quicker - it depends on a whole host of factors (type of weed, time of year, temperature etc).
What are the alternatives?
You can't beat a proper commercial weed killer, these will kill ALL your weeds with very little effort but please take care and always read the label.
If your hellbent on using a homemade weed killer, we have tried and tested them all.
Yes! Salt is another homemade weed killer, it has been used for centuries as a weed killer. Simply dissolve as much salt into a pot of boiling hot water then pour it on your weeds.
The same caveats apply, it won't permanently kill your weeds but the combination of salt + boiling water will be more effective than using hot water on it's own.
Yes! Boiling hot water is one of the safest ways to eliminate weeds, it won't harm your block paving then again it won't kill your weeds either! There is no harm in trying but unless your block paving weeds are really frail you'll not have much luck.
No! Do not add boiling hot water to spray bottles or pressure sprayers. The heat will warp the plastics or tubing damaging your sprayer in the process.
Got more questions? Feel free to post your comments and queries below...