In our modern world, we rely on the results of sophisticated chemistry to provide us with compounds that will keep bacteria and fungi at bay and thus enable our foodstuffs to resist spoilage. Similarly, our gardens can be protected by the use of technologically advanced chemical compounds designed to halt the destruction of our plants by pests large and small. However, in olden times the folks then did not have access to such advances, so one must wonder how they managed with their meat, milk and wine while lacking the benefit of modern refrigeration and chemical preservatives. In many cases, the answer is, quite simply and brightly, silver. Before the advent of modern antibiotics, silver solutions or colloids were in widespread use as antiseptics and even as aids in curing illnesses. Unlike antibiotics, colloidal solutions of elemental silver proved to be useful against a wide variety of pathogens, including bacteria, fungi and even viruses. Records even indicate that milk was prevented from spoiling by dropping a silver coin into the milk jug! So below I'm going to share how you might make use of this ancient knowledge today to combat pathogens affecting your garden plants.
Resistance is Futile
In both medical applications and in the garden, the use of synthetic chemical compounds to fight infections has resulted in the pathogens developing resistance to the chemicals. This, in turn, has forced the development of newer compounds to replace those that are no longer effective. In my research, however, I have found no cases of pathogen resistance developing after exposure to colloidal silver solutions. One reason might be that all exposed pathogens are killed. Silver's mode of action is such that the development of resistance in pathogens is about as likely as a person becoming resistant to suffocation by virtue of no longer needing oxygen for survival!
A quick internet search for information about colloidal silver will yield a large number of results having to do with the use of these solutions for the management of human health. This topic is beyond the scope of this article, so I will state simply that beginning with Hippocrates (the father of modern medicine), silver has been known to have antimicrobial properties. It is this fact that led me to experiment with the use of colloidal silver solutions as a means of fighting pathogens attacking my plants.
A little goes a long way!
Unlike commercial pesticides, the amount of silver in solution needed for the desired effect is quite small. In fact, the effective solutions generally range from 10 to 50 parts per million of silver! This is such a small amount that you could imagine such solutions would be very inexpensive to produce. In fact, they are, but only if you make them yourself! You can purchase ready-made silver solutions at online stores and health food markets, but you will pay a premium for these products. Even at those high prices, though, it was worth it to me to get a small quantity to conduct my tests with. After verifying the usefulness of the solutions, I decided to invest in a small silver solution generator. If you, too, get good results with a small test and you have a large amount of plants or garden area to treat, you will want to consider getting your own generator as well. That way, you can make your own ready-to-use solutions for less than a dollar a gallon!
My initial tests involved simple spraying of the plants with a commercially prepared colloidal silver solution from Purest Colloids. The solutions are pricey, but have a money-back guarantee so if you aren't satisfied with the results, at least you can get your money back. To use it, I just put the solution as-is into a small, clean fine-mist spray bottle and spray it on the plants or soil. You will find very little information on the internet about the use of colloidal silver solutions in horticulture or gardening, but in my opinion that may be the most beneficial use of all for these products. In these low-concentration solutions, the silver is non-toxic to you, pets and the plants, but it kills the pathogens within minutes via a process akin to suffocation. Additionally, the silver is not "used up" in the process, so the same silver particles can go on to kill and kill again. I've even used the solutions to soak seeds in; it is amazing how it prevents the soak solution from going sour, even after several days.
Charge it, or not?
I do need to tell you that not all silver solutions are the same. Without getting too technical, silver can be found in two forms in solutions: ionic and particulate. You'll find that there are different schools of thought on which form is most effective in antiseptic activity, but for horticultural use, your solution is likely to be a mixture of both types, especially if you make it yourself. In colloid chemistry, the type is particulate, or tiny particles of elemental silver which have no charge. These submicroscopic particles are so small that they can stay suspended in a water solution without settling. If the particles settle, they are too big! The smaller the individual particles are, the more effective they are supposed to be.
By contrast, an ionic silver solution is a mix of individual silver atoms that are missing one electron each, meaning that they have a positive charge, like the sodium in table salt that is dissolved in water. This means that they can react with other dissolved ions or charged particles, some of which can combine with the silver and take it out of solution (and thus out of action). This is one reason why the best generator makers recommend that you use distilled water only for the home generation of your solutions. Impurities such as chloride from dissolved salt will cause you to lose all of your silver activity to precipitation.
In the picture above, left, you can see the USP II colloidal silver generator that is offered by Silver Bullet Enterprises. This is the exact one that I have and use for my work.
The best for me?
My suggestion is that you run a small test for yourself first using one of the commercially available solutions. This is most easily done if, for example, you are germinating some seed that you have trouble with in terms of keeping fungi or other pathogens from spoiling the soaking seeds. Once you see that the silver solution works, you can then consider the purchase of a generator.
Photo credit: Public Domain for thumbnail picture of silver nugget, and USP II picture used by permission of Silver Bullet Enterprises.