Do Homemade Herbicides Work?
FOR IMMEDIATE RELEASE
June 10, 2013
Recipes for homemade weed killers abound on the Internet. University of Illinois Extension Specialist Michelle Wiesbrook explains why homemade is not always better.
It's important to keep in mind that anyone can post anything and make it look believable. All that is needed is a recipe using any of the below listed ingredients, an adjective like AMAZING or BEST, and a pretty picture to draw attention to it. These little gems spread like wildfire on social media. Popular mixes seem to include one or more of these main ingredients: vinegar, boiling water, bleach, baking soda, alcohol, salt, dish soap, and borax. There is a certain comfort level associated with these products. They can be found around the home after all. Some of them are even edible!
Unfortunately, the disadvantages of these home remedies often outweigh the advantages. These products don't contain labels with safety or rate information and yet they can still be hazardous to your health. Vinegar can be effective for weed control but only if it is a strong enough grade, which the bottle in your kitchen likely isn't. Vinegar contains acetic acid and acetic acid concentrations over 11% can cause burns upon skin contact. In fact, eye contact can result in severe burns and permanent corneal injury. This is why reading and following the label is so important. There are now registered herbicidal vinegar products you can buy that have use and safety information on their label.
Although borax may sound like a "natural" weed-control method, it is important to remember that it may still be harmful to children and pets. Mixtures should be kept out of their reach. Registered pesticides have been studied extensively and come with labels that tell you how to protect yourself and others. The borax box tells you how to wash your clothes.
One other important disadvantage is that weed control often is only temporary or partial with only the top growth being affected. Boiling water would certainly be death on green leaves. The roots however are protected. If your weed is a perennial or if it has a deep taproot, you can bet it will grow back. Plus, how safe is it to carry big pans of boiling water out the door to your garden? Everything has a risk and furthermore everything can be toxic ... even water.
Some homemade weed killer ingredients can have a lasting effect on the soil making it so that nothing will grow there for a long time. Depending on the area, that may not be too bad you think. Conventional herbicides are made to break down or dissipate in a timely fashion. Unfortunately, the result is new weed growth but at least the soil is healthy and can promote growth. A problem with using borax is that the boron it contains does not break down or dissipate like conventional weed killers do so repeated or excessive applications can result in bare areas where no vegetation can grow. Similarly, salt can be used for long term weed control. But it destroys the soil structure and it is mobile meaning it can move to nearby areas in your garden resulting in unwanted plant damage.
Some claim that their recipes or methods are more effective or longer lasting than registered herbicides. What about their environmental impact? Are these products mobile in the soil? Will they end up in the groundwater? Have they been tested for this use? Would EPA approve of these weed control methods or would they instead insist that the contaminated soil must be removed?
Finally, money savings is often what drives the use of these mixtures. But how much are you really saving? When calculating this, be sure to factor in your personal safety, any potential environmental damage, and the expected length of control. Corners should not be cut when it comes to these important factors ... even if the recipe does sound AMAZING.