How to Use Vinegar to Kill Garden Weeds Safely
Vinegar is a jack-of-all-trades around the home. In addition to the zip it adds to pickles and many other favorite recipes, it's an effective window cleaner, disinfectant, stain remover, and more. But did you know that its many uses carry right on out the door? Yes, vinegar has the ability to help control weeds, too, which can be a win-win if you're looking for products that are less harsh on the environment than many synthetic herbicides. However, you wouldn't want to use this acidic liquid in all areas of your landscape because it could damage any plant it touches. Here's what you need to know to effectively use vinegar as a weed-killer in your yard.
What Kind of Vinegar to Use
Typical white vinegar in the store is 5% vinegar (acetic acid) and 95% water. While this type of vinegar can be used on weeds, it has quite a few limitations. It works best on small, annual weeds that are less than two weeks old, and it will often require several applications to do the job. You can up its efficacy by adding a cup of table salt and a tablespoon of liquid dish soap to a gallon of white vinegar. Usually, this mixture only kills the tops of the target weeds, leaving the roots that can regrow new shoots. And be aware that salt build-up in the soil from repeatedly using this homemade solution can mean nothing will grow in that area at all.
Household vinegar doesn't work well when sprayed on older weeds, perennials, or grasses. Drenching the roots will likely be required (fall is a good time to do this) and even then, it likely wouldn't have much effect. To get rid of tough, perennial weeds, a 20% vinegar solution is best. This type of vinegar, sometimes called horticultural vinegar, can be found at garden centers, farm stores, or online.
How to Apply Vinegar as Weed Killer
The safest places to use vinegar on weeds is in between concrete seams in sidewalks, mulch or gravel paths, and driveways. It's usually easy to spray the vinegar in these areas without getting it on other plants. As with any weed killer, select a day that is warm and sunny to apply it. Avoid days that are windy or rainy. Wind can carry the vinegar to places you don't want it. Rain weakens it, diluting its effectiveness.
When using higher concentrations of vinegar, follow the safety precautions of other herbicides: Don't get it on your skin or in your eyes, and don't ingest it. Unlike household vinegar, the higher concentrated kinds of vinegar can burn skin, harm eyes, and cause bronchitis if inhaled.
Vinegar is non-selective, meaning it will damage any plants and turf grass it touches, not just the weeds you are trying to kill. When you spray the vinegar onto weeds, make sure it isn't hitting other plants. If that isn't possible, paint the vinegar onto the weeds with a brush. Make sure the vinegar makes contact with all the foliage. The acetic acid in the vinegar will burn and dry out the leaves.
For a couple of days after applying the vinegar, you can expect the area to smell like a salad dressing exploded all over your yard. On the plus side, that powerful scent can persuade deer, rabbits, and other pesky critters to steer clear of your garden for a while. Wait at least two weeks before spraying again.