People have been using boiling water to kill weeds since the first patent was made official way back in the 1880s. It’s not really a new thing.
Unfortunately, it’s also not a very practical method for mass growing, so it can’t really be used in commercial farming.
However, the idea of using boiling water as a weed killer on small farms is still there and still viable. It’s called thermal weed control and its whole point is to distort plant cells by shifting heat energy onto them.
It is effective because water is simply one of the most effective energy transfer methods in existence. It’s far more efficient than steam and air, capable of transferring up to twenty-seven times the energy of the latter.
And since water naturally flows down into the ground of its own accord, it’s the easiest method for reaching the roots. That, of course, is compared to steam or air which usually rise first, thus negating some of the heat energy.
Best of all, it’s an excellent alternative to Roundup since pure hot water carries no chemicals and you can get it for free!
Using Boiling Water to Kill Weeds
Plants are delicate, which is one reason boiling water works so well. For everyday garden or sidewalk weeds, it’s the perfect natural weed killer and it’s entirely non-toxic.
So long as you’re careful about where it’s applied, pouring boiling water on weeds won’t harm any of your other plants in the garden. It has no effects whatsoever on you, so long as you dress appropriately.
- Long pants
- Long sleeves
- Closed shoes
The less exposed skin, the better. This will help prevent accidental burns.
Identifying the Weeds
Make sure of what you’re intending to kill before diving in, lest you inadvertently kill something you want to stick around.
Anything hit by accident, regardless of weed or vegetable, will start to wither extremely quickly. You’re probably best recommended to stick to sidewalks and outlying edges of your yard and garden.
The Heating Process
Fill up a teakettle and set it on the stove to boil.
It might be convenient to have a thermometer handy, since the water will need to reach approximately 200 degrees Fahrenheit, as stated by the University of California Integrated Pest Management Online.
You’ll want to check to make sure the water is as close to temp as possible.
Killing the Weeds
Make sure to protect your hands with either Oven Mitts or Kevlar Gloves before turning off the stove and taking the kettle outside.
Be extra careful, but as quick as possible while making your way to the troublesome green pests. The temperature of the water will drop increasingly quickly and it’s important to be precise.
You aren’t going to want to make frequent and time-consuming trips back and forth to boil more water if you can help it. Once in place, hold the kettle’s spout so it tips directly onto the weeds in question.
If you think it’ll make it easier, you can always snip off the fronds of the weeds so that the water has a more direct path into the root system.
Aim carefully for the roots so as not to damage anything else that might be in the path of the killer liquid.
You’re holding a kettle full of potentially dangerous, scalding water designed to kill pesky invaders to your garden. No doubt you’re a little worried about any friendly fire when pouring boiling water on weeds.
The best way to curb this is to squat or kneel and pour the water down from a low height, which will make it splash far less than if you held it up at hip height.
Will Weeds Re-Sprout?
If you do happen to see a stubborn reappearance of one thought long dead, then just reapply the water treatment, same as before. The weed is going to start getting weaker with each new application.
Usually, when using boiling water to kill weeds, it only takes about two or three treatments to see permanent results. However, it’ll be worth it in the end when you don’t have to pull them anymore.
Can You Use Vinegar Instead of Water?
You certainly can.
Simply boil the vinegar and apply it the same way to any stubborn weeds that may even have gotten a real solid foot in the door. And this is a double-whammy.
The heat from the liquids sears the outside while the vinegar invades the internal tissue and finishes the job below the soil.
Just make sure not to overdo it, or you could overwhelm the soil.
The Bottom Line
Weeds are a pain in the neck. They’re the rabbits of the plant world; they multiply like crazy driving everyone crazy from simple gardeners to professional farmers.
They steal valuable nutrients and real estate from crops and they just straight up don’t look appealing.
Chemically composed weed killers are popular to use right now. But more and more studies are cropping up stating how detrimental they are to the health of the crops and the consumers.
Since natural options are more and more in demand, the “boiling water to kill weeds” option is gaining reputation as one of the easiest and most cost-effective natural weed-killing methods.