Every gardener knows that weeds are par for the course when it comes to growing and caring for a patch. Luckily, there are plenty of solutions to help you manage them. While many options involve strong chemicals, you probably have the necessary ingredients for an organic option sitting in your pantry, especially if you plant to make a vinegar weed killer. "There are a lot of harmful over-the-counter weed killers out there," says Eva Reutinger, a horticultural consultant. "Remember, anything you use in your garden seeps into your soil and will affect the groundwater and water running through the storm drains. If you are eating the veggies out of the garden, you want to make sure no harmful chemicals come near it and get into your body!"
Before heading to the store to pick up a chemical-laden iteration, consider making a three-ingredient homemade weed killer, instead. Here, we explain how to make a vinegar weed killer—mixing in dish soap and salt—and how the solution works.
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How Vinegar Kills Weeds
According to Rebecca Sears, chief gardening guru at Seeds of Change, vinegar's acidity plays the principal role in ridding your garden of unwanted growth. "The acid within vinegar breaks down cell walls and removes moisture from weeds, causing them to die off," she says. "Vinegars that you keep in your kitchen, such as white vinegar, contain a level of acidity that can help remove weeds without affecting surrounding plants."
Still, it's important to tread with caution. Reutinger says that though vinegar kills weeds, it is considered a nonselective herbicide. "This means it will kill the weed that is already growing, but you have to be careful because it will kill any other plant it comes in contact with," she says. Reutinger also notes that you should apply vinegar to the weeds on a sunny day. If it's cloudy or the leaves are wet, wait. The sunlight will work with the vinegar to burn the leaves.
How to Make a 3-Ingredient Homemade Weed Killer with Vinegar
While vinegar is the key ingredient, it works best in tandem with dish soap and salt. According to Reutinger, the weed kill recipe calls for mixing together:
1 cup of salt
1 tablespoon of dish soap
1 gallon of vinegar
Blythe Yost, CEO and co-founder of Tilly, an online landscape design company, says that white vinegar is the best choice, since it is colorless and inexpensive. "The salt and vinegar work together to dissolve the plant's cell walls, and the dish soap acts as a facilitator to help the mixture coat the leaves more effectively," she says. "Check the acidity of the vinegar; sometimes, you can find more acidic options. These will be more effective. However, keep in mind [that] although this is made of household products, you should wear eye and hand protection when handling."
Sears agrees with the need for protective gear. "Whenever using vinegar or the vinegar cocktail on garden weeds, be sure to wear gloves to protect your skin from any potential irritation," she says. "I'd recommend wearing long pants and sleeves as well, and of course keep away from the eyes and face." And, as Reutinger says, never spray when it's windy. You'll risk having the mixture blow onto yourself and other plants.
Long-Term Weed Management
Vinegar weed killer is handy, because all that's required to make it are average household items. However, the experts note that while incredibly useful, it shouldn't be your final solution for weed management. "The best kind of weed control is multifaceted," Reutinger says. "You never want to stick to one method; a combination of manually pulling, organic herbicide, and your plantings will be best. Remember to plant ground covers, add mulch, and keep healthy plants. A well-kept healthy garden will naturally have fewer weeds."
While vinegar weed killer is a viable organic solution, you don't want to use it too often, says Sears. "It's best to avoid continuously applying vinegar to your garden as it is an acid and can impact good microbes as well," she says. "The best solution to control weeds is to use a natural mulch like pine needles or grass clippings to prevent weeds from popping up. Vinegar works best on smaller, shallow-rooted weeds. It's less effective on stubborn, deep-rooted weeds like crabgrass."
Ultimately, the best organic weed management involves no products at all. "The best way to kill weeds organically and safely is to pull them by hand or with a weed trowel," Yost says.