Boiling Water Makes a Great DIY Weed Killer—How to Use It Right

It’s a joy to watch your plants thrive, but that happiness can quickly turn to panic when you notice weeds in the garden. Weeds are generally unwanted plants that find their way into your soil and some can be invasive or harm your well-kept plants or lawn. The key to getting rid of these undesired invaders doesn’t have to be a harsh chemical herbicide.

It can be as simple as boiling water, but how does it work? We asked gardening experts about how this simple trick can be a good DIY weed killer—and how to use it safely with your plants.

How to Use Hot Water to Kill Weeds

Using boiling water to eliminate weeds is pretty simple.

1. Fill a tea kettle (with a non-metal handle) with some water.
2. Place it on the stove and heat to a boil, then bring it outside to your garden.
3. Pour it onto the leaves and have it soak down into the roots of the unwanted weeds.

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Why Boiling Water Works to Kill Weeds

The boiling water will put the plant into thermal shock. The rapid temperature change damages the weed’s cells and it causes the plant to dry out quickly.

“That’s why you will see the wilting and then eventually the plant dying,” says Alex Watson, a gardener and the founder of The Garden Guys. “It does do the job if you’re trying to move away from using harsh chemicals.”

Watson suggests using this method during cool weather to enhance the effect of the temperature change on the weed.

Both experts recommend that this method be mostly used with weeds in pesky areas, like sidewalks, driveways, and pathways.

“We find that it’s quite effective on hard surfaces and tight cracks, because the roots are usually quite shallow,” Watson says.

For pesky weeds, the experts advise that the hot water method may need to be used several times before seeing results.

Why Boiling Water Might Not Work on Some Weeds

The hot temperature might be enough to kill certain types of weeds, especially annual plants with roots that are near the top of the soil and not deep into the ground.

Annual weeds, like chickweed, complete their entire growth cycle in a single growing season, but perennials, like dandelions, can continue growing for over two years. Because of this, perennials have deeper roots, like a dandelion’s long taproot.

“If somebody wants to use boiling water, they just have to be careful and make sure that they get it to the plant when it’s really hot,” says Anna Hackman, a farmer and managing member at The Naked Botanical. “But for any perennial like a dandelion, it’s not going to kill it, because it’s just going to kill the top part of it.”

“Anything that has a tap root, which tends to be a perennial, or a perennial that has a lot of roots that go down into the soil, the hot water can’t get to it,” she continues. “By the time it gets down to that soil, the water is cool.”

What to Look Out for When Using Boiling Water to Kill Weeds

When using this method to kill weeds, you’ll need to make sure the weed isn’t directly next to one of your garden’s plants—the ones you planted and are meant to be there. That’s because the hot water isn’t selective when it kills plants and will scorch those around your target, too.

“I just worry, if you’re going into your vegetable garden and you’re killing a weed right by your vegetable, you’re going to kill a vegetable,” Hackman says.

She also notes that the approach shouldn’t be used “in lawns, not in raised beds or vegetable gardens, because I just would be afraid that you would kill the plant.”

Other DIY Ways to Kill Weeds in the Garden

Both Hackman and Watson recommend pulling the weeds out from the ground with your hands or garden tools. Watson advises using a garden hoe to cut off the top of the weed above the soil.

“They start then breaking down and putting nutrients back into the garden,” he says. “They all wilt very quickly, and within a couple of days, you wouldn’t see them.”

If you’re dealing with a dandelion or another weed with a taproot, Watson suggests using vinegar to cause the plant to dehydrate.

“If you use white vinegar from the cupboards, that should start breaking down the plant, and then take it down into the taproot,” he says.