Gardening in the Age of Pinterest: Dubious Online Garden Tips

Social media have made it easy to share information the world around. It has made it easy for people to connect and interact more than humans ever have before.

Gardening is a common theme on Facebook, Twitter and, especially, Pinterest. Ideas are easily shared through these sites. It’s great to see such interest in gardening.

Sometimes, however, these ideas should be taken with a grain of salt. It turns out that you can’t believe everything you read online (surprise, surprise).

Ideas coming from anecdotal observations that haven’t been confirmed or tested through research make their rounds on the Internet, causing frustration — and even danger — for unassuming gardeners. I like to call it “gardening in the age of Pinterest.”

Finding accurate information

As an extension agent, it is my job to teach people about gardening using science-based, and usually peer-reviewed, information that comes from research. This allows me to be confident in the information I provide, that it has been researched by numerous people and has been found to be consistent in a number of settings and conditions.

In the online world, it can be hard to figure out the source of information being shared. Sometimes, the information comes from handed-down information and sometimes it comes from anecdotal information observed by one or a handful of individuals. Sometimes the information comes from groups or individuals with an agenda for or against a certain thing.

Whenever you see something online, especially a questionable “home remedy,” be sure to use your critical thinking skills and do a little research before you add the practice to your own garden.

Land-grant universities are good sources of information. To make sure you get science-based gardening information, you can find university extension resources online. The easiest way to find university information while you are searching online is to add the command “site:.edu” to your search.

If you are on Facebook, I would suggest checking out The Garden Professors. It is a group of professors and extension professionals from around the country that help translate science-based information for home gardeners, and often do some garden myth-busting. There is also a Garden Professors blog at blogs.extension.org/gardenprofessors. (Full disclosure: Yours truly is one of The Garden Professors in the group. Sometimes my articles are shared through the page.)

Misinformation found online

Following are examples of garden misinformation I have found online. The examples come from a variety of sources. Always remember to fact-check!

Homemade pesticide alternatives:

While using pesticides is a matter of personal choice, many people are turning to homemade alternatives for some pest control. While I do think that some of these do work, there are some definite duds circulating out there.

One that I’ve seen is using baking soda instead of fungicide. While changing pH will limit fungal growth, dry baking soda will not have an effect and will quickly wash off.

I’ve also seen insecticides using tobacco. This is a huge no-no! Tobacco carries tobacco mosaic virus, which infects a wide variety of plants including tomatoes, potatoes, etc. The virus can even survive on a smoker’s hand or cigarette butt even after burning.

Pollinators only like native plants:

This is a new one, spurred on by a number of individuals. The premise is that native bees and butterflies can only survive on native plants. While natives are good, there are many plant qualities that make them attractive and nutritious to pollinators. A diverse garden is best for attracting pollinators.

Compost tea suppresses disease:

The practice of making compost tea involves bubbling air through a slurry of water and compost. The idea is to spray this on plants to reduce diseases, since the good bacteria from the tea will keep bad bacteria at bay.

Research by fellow Garden Professor Linda Chalker-Scott, from Washington State University, and others shows that there is no disease suppression (most likely because the bacteria will quickly die off when dried). Other researchers have shown that it doesn’t have any nutritional value for plants, either. It is sort of a garden “magic elixir” or snake oil.

Biodynamic gardening:

This covers a wide range of topics that have been around for decades (or centuries) but have renewed interest from online gardeners. An Austrian teacher and occultist developed a biodynamic gardening system in the early 1920s that included things such as burying a cow horn full of manure underneath your plants.

While that may seem odd, the most common tenet is gardening by the moon phase. This is a common practice in Appalachia that has more to do with folklore or even a belief system (most specifically pagan belief/practice) rather than science (it has never been scientifically proven to have an effect).

While it may not do any harm to plant by the moon phase (and scientists will argue that it has no benefit, but many people believe it does), I’ve seen some take the information to extreme. I once sat through an excruciating talk by someone who said that the moon controlled water uptake by plants.

While many people I talk with hold firm to their belief in gardening by the moon and using an almanac for scheduling, I have to steer clear of any such recommendations since it has no modern scientific basis.

12 thoughts on “Gardening in the Age of Pinterest: Dubious Online Garden Tips

  1. I don’t have time to debate you on compost tea but before you use 1 resource and then site “others” I would suggest you find out more. Yes, compost tea is not a panacea but when developing organic and sustainable systems we do not depend on any singular product. Nobody is claiming compost tea is a fungicide. It is a “system” we are developing where the symbiotic nature is greater than the individual parts. So here is my 1 reference to balance your 1 reference to another university that suggests there are benefits to compost tea and it is not just “snake oil” as you would lead your readers to believe: organic.kysu.edu/CompostTea.pdf. BTW, the google page that I pulled this from has 67,100 hits and yes, Ms. Chalker-Scott comes to the top. Other than compost tea, I think your other observations are right on…

    1. Thanks for the info. However, the source you provide looks to me like it basically says that results are inconclusive and that MAYBE compost tea works, but results are often unpredictable. Hardly a resounding endorsement. The research they quote about foliar feeding is a graduate thesis from my own institution and looks like CT reduces yield in most cases. Understandable, since there is mounting evidence against the effectiveness of foliar fertilization. Most research touting the benefits of compost tea are conducted in the lab under controlled conditions and when replicated in the field show no benefit. Even research from Rodale, which has been touting compost tea, shows unpredictable results and stresses the problem of benefits translating from the lab to the field. http://www.newfarm.org/depts/NFfield_trials/0404/tea.shtml There is also the issue of using improperly composted material in preparing the tea. If the compost doesn’t heat enough to kill of disease organisms, this can be a great way to spread disease such as late blight instead of preventing it. Moreover, the USDA National Organic Standards Board does not recognize compost tea for organic production due to the possibility of contamination with human disease causing organisms through improper composting or brewing. Farmers, or even gardeners, who are selling produce could not use compost tea due to food safety (http://www.ams.usda.gov/AMSv1.0/getfile?dDocName=STELPRDC5058470).

  2. Calling B.S. on number 2…while it’s true that native insects will FEED on alien species, they can indeed only SURVIVE on natives. Many insects utilize ONLY the natives that they have evolved with as host plants. It is imperative that people understand the difference.

    1. Andy, while it is true that a portion of butterflies and moths feed on specific plants in their larval stage, a great number of pollinators are generalists and feed on nectar and pollen of many species. Many of the larva feed on families of plants that have both native and non-native species. There is research that shoes that there is a much more diverse population of pollinators in gardens with mixes of native and non-native plants than those with natives alone. Plus we have the issue of natives not growing well in urban settings or failing due to introduced diseases and pests. A balanced approach is best…a native only policy does not help pollinators.

      1. –There is research that shoes that there is a much more diverse population of pollinators in gardens with mixes of native and non-native plants than those with natives alone.–

        How about providing a link for that. Sounds dubious.

        –Pollinators only like native plants–

        I have never heard anyone say pollinators only like native plants.
        Not even the entomologists promoting native species make that claim.

        Native plants support more species that non-natives.
        If you want to help pollinators, birds and other species you do the most good with native plants.

        A problem with non-natives is they can spread beyond someone’s yard and become invasive in parks and natural areas. Vinca, Asian wisteria and Japanese honeysuckle are just a few classic examples of invasive plants that have done horrible damage outside of the managed garden environment.

      2. A link to research showing that a mix of plants is better than just all natives: http://onlinelibrary.wiley.com/doi/10.1111/j.1752-4598.2010.00103.x/abstract
        Doug Tallamy has a very black/white philosophy when it comes to natives v non-natives for pollinators, and many gardeners consider him the “expert” with an almost cult like following. His take is that natives are good and non-natives are bad. It just isn’t that black or white. Here are links to his theories: http://www.nytimes.com/2015/03/11/opinion/in-your-garden-choose-plants-that-help-the-environment.html?_r=0 http://onlinelibrary.wiley.com/doi/10.1111/j.1523-1739.2009.01202.x/abstract

        While some pollinators are specialists and only feed on a select number of plant species or plants within a certain family (either native or introduced) many, such as bees and beetles enjoy a wide variety of food sources that include natives and non-natives and are considered generalists. There is nothing wrong with native plants, but there are people out there (Tallamy) saying that you should only plant natives when it really isn’t supported by science.

        And not all non-natives are invasive. There are certain traits that non-native plants must have to be considered invasive. To say that all non-natives are invasive is wrong. They have to reproduce rapidly, grow before or after other plants to out compete them, have few or no pests or diseases, live in a wide range of soils or climates, and establish monocultures. Only a very small percentage of non-native species are invasive.

  3. I’d like to give a talk to my garden club about the fun to be had “internet gardening”. Such as identifying plants with Facebook groups and making world-wide pen-pals on Flickr. This blog is a great place to start a discussion about evaluating the information we see shared in all those places.

  4. I found your site through the Renegade Gardener. I’m glad for every balanced and scientific gardening online site.

    I am not a scientist; I study horticulture at a Manitoba college. We were introduced to Ecotea, an organic fertilizer developed by a local company. I cannot argue the science; the complex interactions of the rhizosphere are not my specific area of focus. But I’ve included a link to their website – not as a sales pitch, only because I thought you might want to read about their research.

    http://www.eco-tea.ca

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