I used a very similar mixture two weeks ago with great success. Then a friend posted it on Facebook and some chemist came back with a reply that the combo of the chemicals was MORE toxic than Roundup. There was something in the Dawn detergent we used that combined with something else to become quite lethal. If I remember his response correctly, it was something to the effect that a similar dose of Roundup would be enough to kill 6 rats, while this mixture would kill 60. We used Epsom salts. Any thoughts?
Excellent query and thank you for requesting additional information from us.
I went over this scenario with a Chemist I have worked with and the first thing she stated was, "Everything is relative." Yes, the mixture can actually calculate out to ten times stronger than Roundup, (that is your 6 to 60 rats ratio) but like all chemical mixtures, (roundup or any salt with vinegar and soap) the results will depend on many different factors. For Example: How much was applied, was the dose applied topically, orally or injected? Then the size and weight of the recipient comes into play. When the mixture is more toxic than Roundup, an oral consumption is used. Thus intelligent use of any chemical mixture must be honored, because in all cases, oral consumption of any chemical mixture will do serious harm and should always be kept away from children and animals. When I mix some, I use all of the solution and never store any amount.
So depending on the ratios, too much of anything can be lethal. The brand name of the soap or type of salt will not make one solution worst than another, the amount does. Nevertheless, I find the homemade version comes with more control:
First: I only make what I use.
Second: When the recipe is sprayed onto weeds (best when small and young), if a few drops land on some nearby flowers, they will not die off. The leaf may dry up, but unlike roundup, the flowering plant will not be killed. If a drop of roundup lands on a leaf, it will spread throughout the plant and probably kill the whole plant.
Third: The lingering effect depends on how much was applied and how fast that amount will dissipate. The salt and vinegar mix does dissipate after a few rainy days and will not hinder growth of plants in the future when sprayed or poured on in sensible amounts.
In addition, and I am sure you are aware of this, there are concerns created by reports of various weed killers with various ingredients that "may" be causing a range of health issues, especially in children. I have not read any report on vinegar, salt and soap getting into our drinking water and creating concerns from studies that show the same toxic results from weed killer sprays. The DEC stated 124 detections of Atrazine in 51 locations of groundwater, just on Long Island, New York!
Atrazine is dangerous and is an unacceptable risk to our health and our environment. After being banned in the European Union back in 2004, the United States is just starting to follow with banning the product in spring of 2014. Does the fear of lost business have such a strong grip on America that we have to wait ten years longer to do what the rest of the world already did? This chemical has the largest use, 76 million pounds dumped on our soil each year. Scientific studies proved Atrazine is an endocrine disruptor. The New York Times ran a story in August 2009 about the potential for birth defects or low birth weights with an Atrazine intake well below federal standards. The other two pesticides used in weed killers are Metalaxyl and Imidacloprid. Neither have been addressed as of yet. Only God knows how much time will be needed to ban them.
So since everything is relative and with a larger picture in mind, I choose to use my own homemade mixture and be sensible when using it. I hope this helps. You may visit the original Going True Green Blog post with the Home Made Weed Killer info by clicking HERE.
Bill Lauto, Environmental Scientist at