The Downside To Using Vinegar In Your Garden

While vinegar may seem like a natural way to eliminate unwanted weeds and take care of pesky insects in the garden, you should think twice before using vinegar to kill weeds or pests. Vinegar is capable of destroying weeds and killing bugs because of the acetic acid it contains. Unfortunately, that acid does not discriminate and could harm your garden plants as well as beneficial insects like bees and butterflies.

While household vinegars only have about 5% acetic acid and are milder, herbicidal vinegar can contain up to 30% acetic acid. Not only will this be able to kill your weeds, but vinegar will also burn or kill any other plants it comes into contact with, which has the potential to throw off your garden's ecosystem. While some believe you should be using vinegar in your garden because it can act as a fungicide or a natural animal repellent when used correctly, it's important to consider how the vinegar's acid can negatively affect beneficial insects and pollinators.

While vinegar is often recommended to kill destructive insects, such as spotted lantern flies, it has the potential to kill other helpful insects. According to the Xerces Society for Invertebrate Conservation, vinegar products that have a concentration of at least 10% acetic acid can prove toxic to beneficial insects, including bees and other arthropods, such as butterflies. While household vinegar may not have enough acetic acid to be as harmful, herbicidal or horticultural vinegar is more likely to hurt the butterflies that visit your backyard.

Additionally, there is a chance that acetic acid could negatively affect butterfly eggs. A 2019 study conducted at Georgia Southern University found that in four species of butterfly eggs that came into contact with acetic acid, all of them had an increased number of eggs that failed to hatch. While acetic acid can act as pest control, a high concentration of it can also harm environmentally important pollinators — like butterflies and potentially their eggs — so it may be best to steer clear of using vinegar in the garden.

Because vinegar has the potential to hurt pollinators as well as unintended plants, you may want to implement other ways to deal with pesky insects in your garden. For example, if you're struggling with spider mites, mealybugs, thrips, or aphids in your garden, you might consider using an insecticidal soap. These soaps work best on these soft-bodied bugs and will not leave a residue that's harmful to beneficial insects. You can apply insecticidal soaps to plants pollinators don't like at any time, but if you're trying to tackle pests in your pollinator garden, try waiting until the evening when the butterflies and bees are resting.

On the other hand, you might try applying natural insecticides that specifically utilize fungi or bacteria to get rid of pesky insects. While some of these can target pollinators, others are perfectly safe. For example, if you're trying to eliminate scarab beetles — like the invasive Japanese beetle — bacillus thuringiensis galleriae can be used when pollinators are active nearby without harming them. This is why it's important to research how your pesticide will affect non-targeted insects in your garden as well as your plants.