QUESTION: "I am looking for some info on organic weed killers. I have numerous recipes for organic weed killers with testimonials on how effective they are. They all call for high acidic vinegar or industrial vinegar. I have searched high and low and have not found where I can purchase this miracle of modern man! I have been in the gardening business for years and have had my own business for the past three years (organically based as much as my customers will allow) and find myself feeling grossly inadequate when it comes to this. If you could please let me in on your wonderful wealth of knowledge and pass on the golden key, it would mean the world to me." - Laurie Orsini
ANSWER: There is quite a lot of research under way into the effectiveness of vinegar as a weed killer. I found a online article that you should definitely look at. You can read it at http://www.moscowfood.coop/archive/VinegarKillsWeeds.html
The writer, Patricia Diaz, notes that regular household vinegar is a 5% acetic acid concentration. While this works on some weeds, a greater concentration is needed for other or more mature weeds. By distilling, a 15% concentration can be obtained, and a 30% concentration can be obtained by freeze evaporation. These concentrated acetic acids, if they are derived from plant sources and not from chemicals, are acceptable for agricultural use by the organic community.
The vinegars used in the field tests came from three sources: Knouse Foods, Biglersville, PA, Burns-Philip Food Inc, Baltimore, MD and Heinz USA, Pittsburgh, PA. Be cause the studies are still in their infancy, I don't believe these companies are offering these highly concentrated vinegars to the public, but you might try contacting them.
Note that vinegar with acetic acid concentrations greater than 5% may be hazardous and should be handled with appropriate precautions.
You can learn more about the use of vinegar as a weed killer at this USDA site: http://www.ars.usda.gov/is/pr/2002/020515.htm
Aside from pulling all the weeds out, Cheryl and I have found the best solution is to use organic material to build the soil. If you keep soil healthy, weeds do not seem to do as well. Most of the time you see weeds growing where more desirable plants have a tough time. Again, this is because there is some kind of deficiency. Calcium deficiency is a common cause. Organic products such as Turf Tea Quality Grow, Prosper Soil Conditioner and Smart Coral Calcium can be effective in building healthy, robust soil.
QUESTION: "I have a question regarding a column of yours that was published in the newspaper on July 19, 2006. In the article you discuss the control of the Japanese beetle with the use of "milk spore." Since then, I have asked several area nurserymen if they have this product. None of them had heard of it. Can you please give me more info regarding this?" - Carol Schick
ANSWER: Milk spore is safe around pets and children but kills grubs. It is considered a disease, but it only affects beetle larvae (grubs). Once built up, milk spore can remain dormant in the soil, only reactivating when new grubs appear. It is applied in powder form, using approximately 10 lbs per acre. Here is a useful link I found for you. http://www.diynetwork.com/diy/hi_safety/article/0,,DIY_13930_3632735,00.html Look for the section on "healthier pest control."
You should be able to buy Milk Spore powder at larger garden centers. It's also available online. You can find suppliers by Googling "milk spore powder." I hope you are successful in your battle against the grubs!
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