How to Make Natural Weed Killer With Vinegar
Making your own natural weed killer is an option that many are resorting to, especially since natural and eco-friendly products are on the rise. Using vinegar as an herbicide is nothing new — your grandparents may even have applied it to their own garden. Vinegar is not expensive, and some studies have shown that it can compete with other chemical herbicides on the market.
To make your own vinegar weed killer, you need to know how vinegar works and the pros/cons of using it as an herbicide. It’s an easy process, and we will explain how you can achieve the best results in your garden or yard by following certain guidelines.
What Is Vinegar?
Vinegar is derived from two Latin words: “vinum,” meaning wine, and “acer,” meaning sour. So, it should come as no surprise that it is made from fermented grain, grapes, apples, and wine or any ingredient with ethanol. Full-strength vinegar is highly acidic, being made of acetic acid and water.
There are different strengths of vinegar available. Home use, food-grade vinegar is 5% acetic acid, and it is safe to add to your salads and for cleaning. Once you get past 11% acidity in your vinegar, it becomes caustic and hazardous. At this point, it is not safe for consumption, and you should take precautions when handling.
To be effective as a weed killer, vinegar needs to have a 20% acidity level. Remember, just because it’s natural doesn’t mean it isn’t dangerous. Anything in high concentrations has the potential to cause harm. Luckily, vinegar has a low toxicity and breaks down rapidly in the environment.
Vinegar as a Herbicide
As an herbicide, we define vinegar as non-selective, natural, and organic. Acetic acid is a desiccant that has a drying effect, so the vinegar pulls the moisture from the plants, causing them to die. The vinegar works only by coming in contact with the leaves of the plant; it does not work down to the root, which is why it may take several applications to see results.
Horticultural vinegar with a 20% concentration works the best, but you can use smaller concentrations. Just know that you may not have as good results and it may take more applications. Luckily, vinegar is not expensive, and one gallon will cover approximately 1,000 square feet.
Since it is non-selective, be aware of what other plants are near, as they could be damaged if spray lands on their leaves. It is most useful on gravel walks, patios, and fence lines. Since it is corrosive, we should take care when spraying near fencing, lawn furniture, and masonry, as it can cause these surfaces to stain or corrode.
It works best on small, immature, recently germinated weeds. If you try to spray a six-foot weed, you won’t have much luck killing this plant — it may turn yellow and wither, but within a week or two, it will regrow. Plants with a waxy coating or “hairy” surface may not absorb the vinegar as readily. Mixing in a surfactant, such as liquid dish soap or orange oil, will help the vinegar stay in place on the leaf.
This is a simple solution, and you can find the supplies easily online or at your local garden store.
1 gallon vinegar with 11-20% concentration
1 cup of table salt
1 tablespoon liquid dish soap
Mix all the ingredients in a small sprayer until the salt has dissolved. Do not add water, as this will dilute the solution and it will not be as effective. Take care when handling the vinegar, as it is corrosive. You can use this mixture immediately or store it indefinitely in a cool, dry area.
The salt will further draw out moisture from the plant, making the solution more efficient. Care needs to be taken when applying salt because it will deplete your soil of nutrients, and then nothing will grow in that area. This may be fine in certain areas such as a gravel drive, but if it is your flower or vegetable garden, this could be a concern.
This is a surfactant that will help the vinegar stay on the leaves. Orange oil or yucca extract can be used in its place with the same effect.
Considerations When Using Vinegar Weed Killer
- The effects of the vinegar dissipate within 72 hours, so this means there is no residual action and new weeds will grow.
- Best results will be seen on a warm, sunny day (>70 degrees Fahrenheit).
- Don’t soak the soil surrounding the plant; this could affect the micro-organisms and pH of the soil. In other words, it could decrease soil fertility and nothing will grow well in that area. Plus, it can leach through the soil and damage nearby plants.
- Wait at least 24-48 hours after a rainstorm to spray. Don’t spray if rain is in the forecast in the next 24 hours.
- Do not substitute table salt with Epsom or rock salt. These two salts negatively alter soil composition.
- Clean your sprayer well when you have finished spraying, so the vinegar doesn’t corrode the parts. Store in a separate, non-corrosive, heavy-duty container if you have extra solution.
Safety When Using Vinegar Weed Killer
- Wear long sleeves and pants with goggles and gloves. This spray can cause damage to your skin and eyes.
- Keep pets and children out of the area you are treating until it has dried completely.
- Wait two weeks before applying a second layer.
- Spray when there is no wind; this will protect you and surrounding plants from damage.
Whenever you are dealing with a chemical, even if it is a natural chemical, there are precautions to take. You could use a vinegar solution with a reduced 5% acidity if you prefer, but know it won’t kill the plants as effectively.
By making your own weed killer from vinegar, you will save money and avoid chemicals harmful to the environment. Vinegar is biodegradable and won’t build up in the soil. Vinegar has been around for thousands of years, and more and more people are recognizing it as an effective alternative to weed control.
Know of potential problems when using vinegar with salt, as you don’t want to destroy your soil. You may find the solutions works well enough without the salt. Many gardeners swear that using only vinegar with a surfactant is effective at killing weeds. Either way, give this recipe a try to see if it gets rid of those pesky weeds in your garden.