The Placebo Effect
As gardeners, we often hear of this or that thing, formula, concoction, etc. that will make our tomatoes, peppers, roses, etc. grow bigger, faster or tastier. These pronouncements are often followed up with glowing testimonials of their effectiveness.
You will hear that many common household items will perform miracles when blended together in the correct proportions and sprayed on your whatever. Seeing some of these ingredients (beer, whiskey, urine, tobacco, etc.) makes you wonder exactly what kind of research went into these formulas.
Then you will see the reports of the efficacy of Epsom salts. Officially magnesium sulfate, this material gets its name from the town of Epsom, England where it is present in briny springs. Being highly soluble, it can deliver magnesium and sulfur to plants quicker than using dolomitic limestone, which must be broken down by soil bacteria before these chemicals are available for plant use. There are several schools of thought (of course) when it comes to using Epsom salts. Proponents say it works wonders while others say it should only be used in commercial growing operations where soil tests show a magnesium deficiency due to heavy production and leaching due to irrigation.
And there are the others like manure and herbal teas. Much of the research in these and the others is somewhat sketchy and mostly anecdotal. Someone doing historical research stumbles upon an article by Sir William Flabergast, Duke of Faversham. The good Duke, while stationed with Her Royal Majesty’s Fifth Lancer Dragoons in Budawaddah, observes the native farmers treating their crops with a concoction of local herbs and manures with fabulous results. Unfortunately, this is how many gardening “urban legends” start. An anecdotal observation of an anecdotal concoction that seems to have wondrous results makes its way into gardening lore.
This brings us to the “Placebo Effect.” The placebo effect derives from medical research where a half of a control group is given a new medication and the other half is given a seemingly identical medication that is only an inert substance (simplified explanation). Researchers find that in the control group, those given the placebo will often show signs of improvement. This often, but not always, is attributed to the patient’s belief that they are receiving a drug that will improve their condition, even though they are not.
We as humans always seem to want to believe that there is some “Secret formula” out there that will cure what ails us or our plants. We want to believe that when we do something that is reported as being beneficial that it really works, and from what I remember of the 60’s and 70’s there was a saying- “If it feels good, do it.” So we try one of these secret formulas and our plants seem to respond to it. But is it actually working wonders or did the condition improve by itself? That’s the problem with anecdotal results, there wasn’t a control group to test against so we really don’t know if something worked or didn’t.
And we are not saying that any of the above items don’t work. We like manure and compost teas so we’ll keep using them.
Every garden is different. Soil, moisture, climates- they all change. What may work well in the jungles of Budawaddah, may not translate well to Plano, Texas. If you’ve tried any of the above and they’ve worked for you, wonderful. Even if you just think they work, keep doing it. Just don’t think that if something works well, then twice as much will work better. Overuse of any fertilizing agent can lead to pollution due to the excess that is not absorbed by the plants ending up in our water. Experiment and be willing to take a loss if something doesn’t work out.
As gardeners, we love to experiment with different ideas and plants, but some ideas can have un-intended results, like Kudzu and the Asian lady beetle, so be careful if you’re planning to introduce some exotic species to control slugs in your garden.
Research any new ideas that you may see because what makes sense anecdotally, may not stand up to scrutiny. For example- if composted manure is good for your garden then it must follow that fresh manure would be even better, right? Hopefully you already know the answer to this is a resounding NO! Fresh manure is too high in nitrogen and will burn your plants. It may also contain harmful pathogens which are destroyed in the composting process.
And it never ends, just like being a gardener is a life-long learning process. While putting the finishing touches on this article, we came across an article extoling the benefits of milk and molasses for the garden. This article led to another on the benefits of bio-char, essentially charcoal used as a soil amendment, to improve the soil. As is the usual, the article cites the use of bio-char by ancient tribes of South America (who probably didn’t call it bio-char). It also cites un-named or referenced university studies of the benefits. Again the anecdotal evidence- charcoal absorbs things and is slow to decompose, therefore it must absorb nutrients and make them available to plants is there for the reader to use.
The purpose of this article is not to discredit or debunk any of these practices. Rather it is intended to have the home gardener keep an open mind about them and apply critical thinking to them. In the meantime, someone told us that just spraying our plants with a milk solution will keep the deer away- time to get the sprayer from the shed and give it a try.