Home & Garden Garden 6 Homemade Herbicides: Kill the Weeds Without Killing the Earth By Derek Markham Derek Markham Twitter Writer Derek Markham is a green living expert who started writing for Treehugger in 2012. Learn about our editorial process Updated November 3, 2022 Share Twitter Pinterest Email Treehugger / Caitlin Rogers Home & Garden Planting Guides Indoor Gardening Urban Farms Insects In This Article Expand Drench With Boiling Water Apply Heat Douse With Salt Spray With White Vinegar Combine Salt and Vinegar Use Borax It's been said that weeds are just plants whose virtues have not yet been discovered, but if you're tired of waiting to find out what those virtues are, you might want to use one of these homemade herbicides instead of commercial versions made with synthetic chemicals. What Is an Herbicide? An herbicide is any substance used to kill unwanted plants. While most herbicides are made with synthetic chemicals, natural agents can be used to great effect. Many common weeds can be either food, medicine, or unwanted visitors to the garden, depending on the varieties and how you view them. But if you've eaten all of the edible weeds, and you still need to get rid of stubborn plants in your yard, it's far better for you, your soil, and your local waterways to choose a more environmentally friendly herbicide than those commonly found in the home and garden center. Strong chemical herbicides, pesticides, and fungicides can pollute our drinking water, our groundwater, and surface water. You can avoid these long-term negative effects by choosing a gentler herbicide, which won't contribute to the larger issue of water contamination. These options may be safer for other organisms and wildlife as well. The most environmentally friendly way to get rid of weeds is to pull them up, dig out the roots, let them dry in the sun, and then add them to a compost or mulch pile. However, that method can also take quite a bit of time, so if you're looking for a quicker way to effectively get rid of weeds, one of these homemade herbicides might be the way to go. It's important to note that just because these are "natural" or homemade herbicides, they can still harm your soil, your garden, animal life, or humans. An herbicide is defined as a "substance that is toxic to plants," which means that your garden plants are just as susceptible to these treatments. They could have a negative effect on the soil if applied in large quantities, and they may cause human injuries if misused. 1. Drench With Boiling Water This homemade herbicide is by far the simplest to prepare, and unless you happen to spill boiling water on yourself—please don't do that—is also the least harmful to both people and the environment. Simply bring a big pot of water to boil on your stove, then pour it over the leaves and stems of the weeds you wish to get rid of. Using boiling water is an effective method for killing weeds in places such as sidewalk or driveway cracks, or over a larger area that you'd like to replant after the weeds are gone, as it doesn't leave any residue or have any harmful long-term effects. As with all of these homemade herbicides, it's still important to only apply to the plants you wish to get rid of, as it can easily also kill your flowers or vegetable plants, as well as beneficial creatures. 2. Apply Heat The application of direct heat to the foliage of weeds will cause the plants to immediately wilt, and repeated applications will kill any leaves that may resprout from the roots. A flame-weeder tool is available from home and garden stores, which allows you to apply flame and heat directly to the weeds without catching the whole neighborhood on fire. Warning Dried weeds and grasses can easily catch fire during flame weeding. Do not use this method during dry spells, and check with your local fire department to confirm that the practice is legal in your area. 3. Douse With Salt Sodium chloride, or common table salt, is an effective herbicide. Because salt can have a detrimental effect on the soil, it's important to only apply it directly to the leaves of the weeds and not soak the soil, especially in garden beds with other, more desirable, plants. Here's how to make a salt spray: Dissolve 1 part salt in 8 parts hot water. (It can be made stronger with up to 1 part salt to 3 parts water.)Add a small amount of liquid dish soap, which helps the mixture adhere to the leaf surfaces. Pour the solution into a spray bottle. To apply, spray the leaves of the weeds, making sure to cover or tie back any nearby plants you don't want to kill. Be careful to not soak the soil, and keep this mixture away from cement sidewalks or driveways (it may discolor them). Multiple applications may be necessary. 4. Spray With White Vinegar Spraying white vinegar on weed leaves will cause the weeds to die off, making room in your yard for more desirable plants. The white vinegar sold in grocery stores is about 5% acetic acid, which is usually strong enough for most weeds, although a more industrial strength version (up to 20% acetic acid) is available in many garden supply stores. The vinegar can be applied by spraying full-strength onto the leaves of the weeds, being careful to minimize any overspray on garden plants and nearby soil. Repeated applications may be necessary, and the addition of a little liquid dish detergent may improve the effectiveness of this homemade herbicide. Warning Industrial strength vinegar can be harmful to the eyes and burn skin. Only use vinegar of this concentration while wearing goggles and protective gloves. 5. Combine Salt and Vinegar Another common homemade herbicide recipe calls for combining table salt or rock salt with white vinegar (1 cup salt to 1 gallon vinegar), then spraying this mixture on the foliage of weed plants. Adding liquid soap is said to help the efficacy of this weedkiller, as is the addition of certain oils, such as citrus or clove oil. 6. Use Borax Borax, which is sold as a laundry and cleaning product in many grocery stores, can help lend a hand in the yard as an herbicide. Add 10 ounces of powdered borax to 2.5 gallons of water, mix thoroughly, and use a sprayer to coat the leaves of unwanted weeds in your yard. Keep overspray off of any plants you want to keep, avoid saturating the soil with the solution, and avoid contact with bare skin.