Apple cider vinegar (ACV) is a common pantry item often explored as a natural alternative to synthetic chemical herbicides. The short answer is yes, ACV can kill grass, but its effectiveness depends heavily on the product’s concentration and application method. This natural approach is non-toxic to humans and pets in its household form, offering an appealing option for spot-treating areas like walkways or patio cracks. Successfully eliminating established grass requires a deeper understanding of ACV’s chemical action and proper application.
The Herbicidal Action of Apple Cider Vinegar
ACV acts as a herbicide due to its active ingredient: acetic acid. This organic compound gives vinegar its sour taste and its plant-damaging properties. Acetic acid functions as a non-selective, contact herbicide, meaning it only harms the plant tissue it physically touches.
When the acid solution is sprayed onto grass blades, it rapidly destroys the plant cell membranes. This cellular breakdown causes the contents of the cells to leak out, leading to desiccation, or rapid drying out. The foliage will show signs of damage, often appearing scorched or burned, sometimes within hours of application.
Crucially, this action is limited to the above-ground parts of the plant. Since acetic acid does not travel systemically or penetrate deep into the soil, it generally fails to kill the deep root system of established grass or perennial weeds. While the visible green parts may die back quickly, the plant’s root crown can often regenerate, necessitating repeated applications for complete control.
Application Strategies for Maximum Effect
The concentration of acetic acid is the most important factor determining ACV’s herbicidal power. Standard kitchen ACV contains about 5% acetic acid, which is generally only effective at killing very young seedlings or soft, annual weeds. To reliably kill established grass, a much stronger solution is needed, typically horticultural vinegar, which contains 10% to 20% acetic acid.
Using these higher concentrations increases the risk of skin and eye irritation, so safety gear like gloves and goggles is necessary during application. To enhance the solution’s effectiveness, add a small amount of liquid dish soap. The soap acts as a surfactant, helping the solution spread and stick to the waxy surface of the grass blades.
The best application time is during hot, sunny, and dry weather conditions. High temperatures and direct sunlight accelerate the drying process initiated by the acetic acid, improving the burn-down effect. Saturating the target area is necessary, but avoid spraying on windy days to prevent drift onto desirable plants. Multiple applications spaced a week or two apart are often required for long-term suppression.
Consequences for Soil and Surrounding Vegetation
A significant consideration when using ACV is its non-selective nature. The acetic acid destroys the cells of any plant it touches, meaning overspray or drift will damage or kill desired lawn turf, flowers, or garden plants indiscriminately. Precision application, such as spot treating or applying directly to the base of the unwanted grass, is necessary to protect surrounding vegetation.
The high acidity of the vinegar can also temporarily impact the soil environment. Applying concentrated acetic acid significantly lowers the soil’s pH, making the application area more acidic. This change in pH can harm beneficial soil microorganisms and may make the area unsuitable for immediate reseeding or replanting.
The solution breaks down quickly and leaves no residual activity in the soil. This lack of residual effect is a benefit for organic concerns, but it means new grass or weeds may germinate soon after treatment. For robust, established grass varieties, the temporary nature of ACV may require a more persistent approach.