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 large-scale operations, so it can’t really be used in commercial farming.
However, the idea of using boiling water as a weed killer for small backyard gardens is still there and still viable. It’s called thermal weed control, and its whole point is to destroy plant cellular material with the heat from the hot water .
It works because water is simply one of the most effective energy transfer methods in existence. It’s far more efficient than air, capable of transferring heat 23 times faster.
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 air, which usually rises first, thus negating some of the heat energy.
Does boiling water kill weeds? Yes, it does. Best of all, it’s an excellent alternative to Roundup since pure hot water contains no chemicals, and you can get it for free!
Hot Water for Weed Control
Plants are delicate, which is one reason boiling water works so well. For small gardens, sidewalks, and between block paving, it’s the perfect natural weed killer, and it’s entirely non-toxic.
So long as you’re careful about where you apply it, pouring boiling water on weeds won’t harm any of your other plants in the garden or lawn grass nearby.
It also has no effect whatsoever on you, as long as you dress appropriately and handle it with caution.
- Long pants
- Long sleeves
- Closed shoes
- Safety gloves
When killing weeds with boiling water, the less exposed skin, the better. This will help prevent accidental burns.
Identifying the Weeds
Make sure you know what you’re intending to get rid of before diving in, lest you inadvertently eliminate something you want to keep.
Anything hit by accident, regardless of whether it is a weed or vegetable, will start to wither extremely quickly. This method works best for sidewalks, cracks, between pavers, and the edges of your lawn 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 be over 200 degrees Fahrenheit .
You’ll want to check to make sure the water goes over this temperature to send the weeds into thermal shock.
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 weeds. 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.
If you think it’ll make it easier, you can always snip off the fronds of the weeds. This way, 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 hot water. If you’re not careful, the boiling water will also kill grass, clover, dandelions, and other plants you want to keep.
You’re holding a kettle full of potentially dangerous, scalding water designed to destroy weeds in your garden. No doubt you’re a little worried about the heat when pouring the boiling water.
The best way to curb this is to squat or kneel and pour the water down from a low point. This will make it splash far less than if you held it up at hip height.
Will Weeds Grow Back?
If you do happen to see a stubborn reappearance of weeds thought long dead, then just reapply the water treatment as before. The plant is going to start getting weaker with each new application.
Usually, 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?
Yes, instead of water, you can certainly use this handy household product to help control weeds. Read: How to Use Vinegar to Kill Weeds: Basic Guide
Simply boil the vinegar and apply or spray it in the same way on any stubborn weeds that you want to eliminate.
And this is a double-whammy as it works both ways. The heat from the hot vinegar will sear the exposed portion of the plant while the acid from the vinegar invades the plant’s internal tissue and finishes the job below the soil.
Just make sure not to overdo it, or you could overwhelm the soil.
Weeds are a pain in the neck. They’re a nuisance to the crop world as they multiply rapidly, driving everyone crazy, from beginner gardeners to professional gardeners.
Weeds steal valuable nutrients from crops, and they just don’t look appealing.
Chemical herbicides are popular right now. But more and more studies are surfacing stating how harmful these chemical treatments are to the health of the crops and the consumers.
Since organic options are more and more in demand, utilizing the “hot water sprayer for weeds” method is gaining a reputation as one of the easiest and most cost-effective natural weed-killing options.