SUPER Thriving Lettuce?

The Garden Professors have previously written about the ubiquitous garden center product, SUPERthrive, here and here. The manufacturer claims a plethora of beneficial uses for SUPERthrive —everything from Christmas tree care to turf to hydroponics. They claim SUPERthrive will “revive stressed plants and produce abundant yields” and that it “encourages the natural building blocks that plants make for themselves when under the best conditions” thus “fortifying growth from the inside out,” but I know of no body of rigorous, peer-reviewed literature to support any of those claims (1, 2, 3, 4). In fact, I’m not entirely sure what those claims really mean, but I’m encouraged on their website and bottle to use it on every plant, every time I water, to receive these amazing benefits!

A test case

The hydroponics claim intrigued me because during the winter months I grow plants hydroponically under lights. One of the benefits the manufacturer claims is “restores plant vigor” and “works with all hydroponics systems.” As a plant scientist, and knowing something about the ingredients, I was skeptical to say the least, but I thought that if SUPERthrive was going to show any beneficial effect it would surely be in hydroponics since that is a more uniform environment than outdoors. So, I shelled out my $11 for 2 oz (the things we do for science!) and set off to design a simple experiment.

The hypothesis

A typical experiment like this starts with what we call the null hypothesis (denoted “H0”). The null hypothesis is defined prior to the experiment and often states that we think there will be no difference between the treatment and control. In this case, my null hypothesis is that the SUPERthrive treatment will have no effect on the mean fresh weight of the harvested lettuce relative to the control lettuce. Note that I haven’t made any hypotheses about other parameters that might be important, e.g., flavor, compactness, number of leaves, color, disease incidence, survival rate, etc. For this experiment I am interested in only one thing: total harvested weight as a signifier of healthier plants.

After the data is collected and analyzed, we decide whether to accept or reject the H0 by running an appropriate statistical test. If there is no statistically significant difference, then we cannot reject the H0—that is, we accept the H0 that there is no difference between treatment and control. If there is a statistically significant difference between treatment and control, then we say we reject the H0 and conclude that the treatment did have an effect. Keep in mind, sometimes no difference between treatment and control is a good thing, e.g., in toxicity studies.

Experimental design

With my skeptical spectacles on, I set up my experiment to test my hypothesis. I made a six-gallon batch of hydroponics nutrients suitable for leafy greens. I split the batch in half and added SUPERthrive, per the manufacturer’s dilution recommendation, to one of the three-gallon aliquots as the treatment. I then divided the control and SUPERthrive treatment each into six individual, identical, two-quart containers. I thus had six independent replicates of a treatment and a control. (See Figure 1 below for a schematic of the experimental design.)

Figure 1. Outline of experimental design

To further avoid any experimenter bias, I had my wife assign numbers randomly to each container, record which were SUPERthrive treatment and which were untreated control, and then re-sort all the containers. I had no idea which containers contained which nutrient mix. I did not open the “secret decoder envelope” until after all measurements were complete!

Figure 2. Identical 2 quart containers randomized on day 1 in the hydroponics solutions. This kind of hydroponics is called “Kratky” or passive. Enough nutrient solution is supplied at the beginning to last the plant for its entire life-cycle.

Into each of the 12 containers I placed a 12-day-old lettuce seedling, taking care to select plants that were of equal size and leaf number. The containers were then placed under my lights (cool white T8 fluorescent) for the remainder of the experiment. I rotated the rows of plants several times to try to control for any edge effects in my grow area. After 30 days in the containers, I harvested and weighed each plant.

Figure 3. Plants after 30 days of growth.

What did my experiment show?

The graph below is a box and whisker plot that shows the spread of the data and the mean for each group in grams of harvested fresh weight of the plants (roots were removed). In my experiment, the SUPERthrive treatment showed a clear drop in harvested fresh weight! In fact, the heaviest SUPERthrive plant weighed less than the smallest control plant, and the SUPERthrive set was much more variable in harvested weight. These results surprised me a bit.

Figure 4. Box and whisker plot of lettuce plant fresh weight. Master Blend: Master Blend nutrients; Master Blend + ST: Master Blend nutrients plus SUPERthrive (0.9 ml/gal.)

A standard statistical test (Student’s T-test, unpaired, two-tailed) was performed to show that that there was in fact a statistically significant difference (p<<0.01) between the two groups. Thus, we can reject the H0 (remember our null hypothesis is that there will be no treatment effect) and conclude that there is a difference between treatment and control harvested weights, with the treatment mean plant weight being significantly smaller than the control mean plant weight.

What can we make of this experiment?

Well, we need to keep in mind a few things.

1) Six replicates is a very small sample size; this could be a spurious, unlucky result. There is always some distribution of growth rate, even in a uniform genotype. Did I get unlucky and happen to put six plants that would always be on the smaller end of that distribution into SUPERthrive?

2) After analyzing the data, I discovered that four of the SUPERthrive plants ended up in the same row and were the smallest heads in the experiment (sometimes you flip a coin and get four heads in a row!). Could this be the reason for the unexpected results? The other two treated plants were in the other two rows, but neither was as large as the smallest control plant.

3) I do not have a perfectly controlled environment like one would find in a lab or even in a larger growing facility. However, something marketed with such aggressive claims of amazing plant health benefits and vigor should give a noticeable effect under a variety of imperfect, real-world conditions, such as those one would find in a home garden situation, don’t you think?

4) Perhaps my plants were already growing at their maximum potential and there was nothing for SUPERthrive to “improve.” Afterall, hydroponics indoors is already a relatively stress-free environment, as the SUPERthrive manufacturer also points out. Then what do they think their product is improving in hydroponics? Would I have seen an effect under less-than-ideal or more stressful conditions then? This could certainly form the basis of other testable hypotheses.

Conclusions

What I think we can conclude is that in this experiment, with this genotype of lettuce, and under these hydroponics conditions and environment, SUPERthrive had no positive effect whatsoever and may have even had a negative effect. Under other conditions would one see a positive effect? Possibly. Would different plants or genotypes respond to the SUPERthrive differently? Possibly. We must always be careful of over-extrapolating both positive and negative results from a single experiment.

But, because the individual ingredients have not been shown to provide any beneficial effect, and no plausible mode of action is given by the manufacturer for their broad general claims, we should remain highly skeptical. As pointed out in the previous post, the SUPERthrive manufacturer has certainly had plenty of time to scientifically demonstrate efficacy of their product, since they proclaim to be “always ahead in science.”

Because the results showed a clear and unexpected negative effect, the experiment surely needs to be repeated. Repetition is a central tenet of science. I hope to share additional results with you in a post later this spring—after all, I have a whole bottle of SUPERthrive and we love salad!

References

  1. Banks, Jon & Percival, Glynn. (2012) Evaluation of Biostimulants to Control Guignardia Leaf Blotch (Guignardia aesculi) of Horsechestnut and Black Spot (Diplocarpon rosae) of Roses. Arboriculture & Urban Forestry. 38(6): 258–261
  2. Banks, Jon & Percival, Glynn. (2014) Failure of Foliar-Applied Biostimulants to Enhance Drought and Salt Tolerance in Urban Trees. Arboriculture & Urban Forestry 40(2): 78–83
  3. Chalker-Scott, Linda. (2019) The Efficacy and Environmental Consequences of Kelp-Based Garden Products.
  4. Yakhin Oleg I., Lubyanov Aleksandr A., Yakhin Ildus A., Brown Patrick H. (2017) Biostimulants in Plant Science: A Global Perspective. Front. Plant Sci., 7:249

Not all Extension publications are created equal

(A friendly caveat – this post does not lend itself well to images. So the pictures here are simply eye candy from my 2019 trip to London to reward you for considering this visually drab but important topic.)

The actual “whomping willow” in Kew Gardens

I’ve been involved in Extension education for 17 years and one of the most important things I’ve learned is that Extension audiences want information that’s easily understood and has obvious practical use. Most peer-reviewed research articles are written for academic audiences, so only the most persistent nonscientists will slog their way through pages of dense, technical writing.  It’s up to Extension educators to accurately translate and summarize technical scientific information for use by the public.

Epiphyte “tree” in Kew Gardens glasshouse

Extension is part of the American land-grant university system and extends traditional academic teaching to citizens statewide (hence the term “extension”). In addition to providing seminars and workshops to interest groups, Extension publishes educational materials in-house and provides them at low or no cost to their clientele.

The Bonsai Walk at RHS Wisley Gardens

But here’s the problem: the standards for Extension publications are set by each university. Unlike the peer-review system adopted by reputable journal publishers, Extension publications can vary widely in quality. Some universities have adopted a system that parallels that of scientific journals in that they require double-blind peer review. But many universities have not – and this means that looking for Extension publications on a particular topic results in a collection of materials with contradictory messages. This is incredibly frustrating to confused nonscientists and to Extension faculty who have to sift through the mess to find publications that are relevant and science-based. As a result, Extension publications are often regarded with suspicion by both nonscientists and academic faculty (who often do not have the disciplinary expertise to sort through the mess). Since I was a traditional academic before entering Extension, I have a foot in both camps.

Sunken gardens at Kensington

Nonscientists are probably not going to have the disciplinary expertise to tease out the good stuff from the dreck. But they can look for some indicators that will help them identify the most reliable publications. Here’s a checklist to start the process: the more “yes” answers you have, the better the chances are that the information is reliable.

  1. Is the author identified? Anonymous publications are not reliable.
  2. Is the author an expert? Expertise is determined by advanced degrees (at least a Master’s degree) in the subject matter.
  3. Is the publication peer reviewed? There should be a logo or a statement on the publication that says so.
  4. Is the publication relevant? High-quality Extension publications targeted towards commercial agricultural production are usually inappropriate for use in home gardens and landscapes.
  5. Is the publication current? Information relative to urban horticulture and arboriculture is rapidly changing. Publications over 10 years old likely do not contain the newest information.
  6. Are there scientific references included, either as citations or as additional readings?

As necessary as this process is for identifying reliable information, there can also be negative outcomes. Universities that do not have a rigorous process for publishing Extension materials put their Extension faculty into the uncomfortable position of having to defend their work when it’s questioned. It would benefit all parties for every land-grant university to institute a rigorous, peer-reviewed process for their Extension publications.

My favorite ad at the tube station

Hydroponics for the Holidays? Home Systems are a hot holiday gift list item

Systems to grow fresh produce in your home using hydroponics or other automatic processes have been popular for several years but seem to be even more popular this year with more folks home and looking for something to do and hoping to produce their own food.  As a result, these systems are popping up on holiday wish lists and gift buying guides all over the internet.  But are they worth it?  And if so, what should you look for in a system? 

First off, what are these systems? And what is hydroponics?  Hydroponics is the process of growing plants without soil in a aqueous nutrient solution.  Basically, you provide all the nutritional needs of the plants through nutrient fertilizers dissolved in water.  These systems can grow plants faster and in a smaller space than traditional soil-based production. It also allows you to grow plants indoors and in areas where you would not normally be able to grow.

This Aerogarden (which is the previous generation) has a digital brain that controls light and water schedules for the specific growth phase of the plant and yells at you when it thinks you need to add more fertilizer solution.

As for systems, you might have seen what is probably the “oldest” one on the market – the AeroGarden.  Since it is the oldest and most common, that’s the example we’ll be staying with.  It has been around a few decades and has evolved from a basic electronic system to fully automatic, “smart”Bluetooth connected systems that you can control with your phone.  In recent years there have been many new systems come onto the market at all different sizes and price points.  A quick search of online retailers will usually provide an array of options – from DIY kits to plug-and-play enclosed systems such as “Click & Grow” and “Gardyn”. My only experience is with the Aerogarden system, so I can’t speak to any of the others (though I’d love to try them out!).

The answer to “are they worth it” is up to you, really.  Most home based hydroponic or aeroponic systems offer convenience, but at a cost.  Most cost several hundred dollars and are small, so they produce a small amount of produce (or other plants) at any one time. So you have to determine what goals you, or your intended giftee, have with the system. 

“Baby” lettuce, 18 days after sowing. The current version of this 9-plant Aerogarden system, called the “Bounty”, retails for $300 but you can usually get it for under $200 on sale.

The benefit of the “plug-and-play” enclosed systems like the AeroGarden is that basically you can take it out of the box, set it up in less than 10 minutes, and have some fresh lettuce or herbs in a few weeks.  It controls the water cycles, lighting, and all other conditions for growth.  You just drop in pods that contain the seeds suspended in a spongy-material.  The smallest system, that holds 3 plants, retails for $100.  As an additional expense comes from buying refill kits to replant. The mid-size systems are the most common and range from $150-$300.  The largest system, the “XL Farm” retails for $600. But these systems are commonly on sale at pretty significant discounts. 

For many systems, you typically buy a new set of pods (there are different plant variety selections), but there are pods you can buy to assemble your own using your own seeds.  For the AeroGarden, the pod kits range from $15 up to $30 to grow up to 9 individual plants. There are other plug-and-play systems on the market, as well as some kits that are more build-your-own and less automated. 

No matter which systems you buy (or gift), keeping these costs in mind is important.  If you’re looking for a fun and easy activity with the benefit of a little fresh produce and aren’t as concerned with production costs these systems may be for you – and if you are giving or getting them as a gift that definitely makes it more economical. But given the cost of the plug-and-play systems and the refill pods, they will never be an “economical” option for producing your own food.  If you are wanting to produce food on a budget and you’re interested in home hydroponics, look for plans to build your own or buy a DIY kit. 

GPs at the Tradeshow: Looking for snake oil and finding…..the dirt on tillage

The Annual Meeting and Professional Improvement Conference of the National Association of County Extension Agents is that one time of year where extension agriculture professionals gather to share ideas, give talks, network, and let their hair down. The name of the organization is a bit outmoded: many states no longer call their extension personnel agents, but rather educators, experts, professionals, area specialists, and the like. Most aspects of agriculture are included: from the traditional cows and plows of animal science and agronomy to horticulture and sustainable agriculture (I’m the outgoing national chair of that committee). There’s also sharing on agriculture issues like seminars on engaging audiences about genetic engineering, teaching and technology like utilizing social media and interactive apps, and leadership skills.

It is the one time every year or so that Linda Chalker-Scott, grand founder of the Garden Professors, and I get to hang out. If we’re lucky we’ll meet up in some sessions, chat in the hallways, or grab a drink. But one of our favorite conference activities is taking a turn around the trade show floor. This is where companies and organizations are vying for the attention of extension educators to show them their newest equipment and products….we are, after all, the people that share growing and production information with a great number of potential clients across the country.

Since the organization runs on money, almost no company that comes calling with the money for a trade show spot is turned away. This means that the products may or may not stand up to the rigors of scientific accuracy. In years past we’ve found snake oil aplenty, like magical humic acid that is supposed to be this natural elixir of life for plant growth. The only problem is that humates don’t exist in nature and there’s little documentation of any effect on plant growth. The product that was supposed to be this magic potion was created from fossil fuels and no actual peer-reviewed research was offered by the company – hardly convincing. There were magic plastic rings that supposedly acted as protective mulch around mature trees and could slowly release water, except that mature trees don’t really need protective mulch and the amount of water would be negligible to a tree that size. So will we be smiling or scowling when we’ve made our way through the trade show.

Right off we set our sites on a company starting with “Bio”, which can be a good indicator of questionable rationale. That lit up the first indicator on our woo-ometer. Beneficial bacteria you apply to plants/soil: woo-ometer level two. So LCS and I engaged the representative. Asking about the product and what it does. We learned about their different products that could help increase the rate of decomposition of crop residues in farm fields, of turfgrass improvement, increased crop production, and treatment of manure pits on dairy and hog farms (which, if you’ve ever experienced one, you’d know would benefit from any help they can get in terms of smell).

Most of the products like this give vague descriptions of the beneficial bacteria it contains. They’re akin to compost teas that can have any number of good, bad, and downright ugly bacteria and fungi in them.  Since you don’t know what’s in these products, any claims on soils or plants are suspect at best. However…our rep went on to tell us that the company created blends of bacteria from specific strains that had been researched for their effects on decomposition, soil nutrient availability, and plant growth. There was a brochure with the specific bacteria listed, along with studies the company had conducted.

We asked about peer-reviewed research, which is our standard for evidence here at the GP, and while he had no results to share he assured us that university-led research is currently in the works. And as we’ve stated in regards to applying of beneficial bacteria to soil – while there’s little evidence showing the effectiveness of applying non-specific bacteria to plants, using directed applications of specific bacteria which have been tested for specific functions are supported by research. So our woo-meter didn’t fully light up. We reset it and continued the hunt.

We scoured the rest of the trade show and found one other soil additive that lit up the first lights of our woo-meter, but the rep must have been out for lunch so without anyone to talk to we couldn’t confirm woo or no-woo.

However…..we did find something spectacular! The local employees of the USDA NRCS (Natural Resources Conservation Service) had an interactive demonstration of soil, specifically showing the benefits of reducing or eliminating tillage. The NRCS works with many farmers to incorporate conservation practices on farms, including no-till production, by providing technical assistance, farm plans, and even grants, cost-share, and easement programs. Many farmers have benefitted from their grant for season extension high tunnels (which are seen as a soil conservation technique, since they shelter soil). We were so enamored with the demonstration, we asked them to do it again…so we could record it. So, for your viewing pleasure check out the video below where you can see how well no-till soil holds its structure while tilled soil falls apart. This effect is from the exudates from all the beneficial microbes in the soil that act like glue to promote good soil structure. We’ll let the video speak for itself……

So not only does the trade show get a smile instead of a scowl from us, but also two thumbs up! Either there has been some weeding out of the trade show sponsors, maybe the snake oil salesmen didn’t get the traction they were hoping for at the conference, or hopefully some of these companies have failed to reach an audience with their pseudoscience.

 

Is it good advice? Or is it CRAP?

In my educational seminars I’ve long shared a version of the CRAAP test (currency, relevance, authority, accuracy, and purpose) for analyzing information related to gardens and landscapes. My version is CRAP (credibility, relevance, accuracy, purpose), and we’ve published an Extension Manual that explains in detail how to apply it. This past week I was at the Philadelphia Flower Show participating in Bartlett’s Tree Care Update panel. Given that the theme of the show was “Flower Power,” I figured that a talk on Magical Mystery Cures was in order. And the 1960’s was the decade where the late Jerry Baker gained prominence as a garden authority – and whose presence is still widely felt nearly 60 years later.

And anthropomorphizing of plants begins….

 

 

 

 

 

 

 

 

 

Now, I could spend the rest of the year discussing all of Jerry’s advice, tips, and tonics for gardens – but it’s more useful to determine whether he is a credible source of reliable information. So let’s apply the CRAP test.

C = credibility. What are Jerry’s credentials as a garden expert? It’s easy to find this information from the internet, including the Jerry Baker website. He had no academic training in plant or soil sciences but started his career as an undercover cop who often posed as a landscaper. His books are all popular publications, meaning they have not gone through critical review by experts before publication.

R = relevance. For our purposes, his information is relevant to our focus of managing gardens and landscapes (as opposed to production agriculture, for instance).

A = accuracy. Jerry’s advice is not based on any scientific source. He relies on common-sense approaches, folklore, and his grandmother’s advice. In fact, many of his assertions are at odds with published scientific evidence. Now, science evolves, and older scientific publications are sometimes found to be inaccurate after new information comes to light. If Jerry’s books were meant to be accurate sources of information, they would be updated with new findings as subsequent editions were published. This is what happens with textbooks, for example.

P = purpose. What is Jerry’s ultimate purpose? It’s sales. There’s no way around this conclusion. Over twenty million copies of his books have been sold, and during his career he became the spokesperson for several gardening products. Probably the most well-known of these was the Garden Weasel (which parenthetically is a great way to destroy fine roots and soil structure). There’s no doubt he was a brilliant self-promoter and marketer. But he was not a reliable resource, and many of his “tips and tonics” are extraordinarily harmful to plants, pets, and the environment.

“Garden Weasel” courtesy of Wikipedia

While I was wrapping up my research on Jerry Baker I was particularly taken by a chapter in one of his books (one of his Back to Nature Almanacs) called “The Tree Quacks.” I thought some of these quotes were particularly ironic:

The source…

…and the quotes

 

 

 

 

 

 

 

Imagine my surprise when I discovered that these quotes were actually not his own. In fact, the entire chapter was plagiarized from a 1964 article by John Haller in Popular Science, which is online. This action is uncomfortably similar to his 1985 trademarking of the phrase “America’s Master Gardener,” 12 years after the Master Gardener program was formed (but not trademarked) at Washington State University.

Text from 1964 Popular Science article

I hope this post has helped you learn to analyze the credibility of information and information sources. If so, you can claim the of America’s Master CRAPper ™!

Native vs. nonnative – can’t we all just get along?

Probably the most contentious gardening topic I deal with online is the native vs. nonnative plant debate. This, unfortunately, is a debate that is more based in emotion than science, and I don’t intend to stir that pot again. We’ve discussed it on this blog before (you can find a list of them here), and I’ve published both a literature review and a fact sheet on the science relevant to tree and shrub selection. What I want to do in this post is compare two research papers, both in peer-reviewed journals, that come up with dramatically different conclusions.

The first has been getting a lot of publicity on the web and in social media. It was published just two days ago, but because of widespread PR prior to release it appears over 37,000 times in a Google search. The title “Nonnative plants reduce population growth of an insectivorous bird” – and much of the prerelease publicity about the article spells doom and gloom. It’s a message that gets traction.

The second was published a year earlier and is entitled “Native birds exploit leaf-mining moth larvae using a new North American host, non-native Lonicera maackii.” It appears 194 times in a Google search, even though it’s been available for over a year.

Amur honeysuckle (Lonicera maackii)

The reason I’m singling out these two articles is they have completely different messages – and one of them is not being heard as loudly as the other. The first focuses on a single bird species, the Carolina chickadee (Poecile carolinensis) and its diet in urban landscapes. Their conclusion: “…properties landscaped with nonnative plants function as populations sinks for insectivorous birds.” Thus, any gardener who happens to use introduced ornamental plants in their landscape is made to feel guilty for starving their insect-eating birds. (As an aside with my manuscript reviewer hat on – this statement has no business being in an abstract as it overextrapolates the research on one species to include ALL insectivorous birds.)

Carolina chickadee (Poecile carolinensis)

Black-capped chickadee (Poecile atricapillus)

 

 

 

 

 

The second article has a different focus. It reports the feeding of black-capped chickadees (Poecile atricapillus) on the larvae of a leaf-mining moth (Phyllonorycter emberizaepenella). While leaf miners are common food items for chickadees, the point of this article was to document the host of the leaf-miner – a nonnative and particularly invasive species of honeysuckle (Lonicera maackii).

Honeysuckle leaf miner (Phyllonorycter emberizaepenella)

 

Honeysuckle leaf miner damage

 

 

 

 

 

Chickadees as a group are particularly adept at finding and consuming leaf miners, whose tunnels normally protect them from insectivorous birds. Chickadees move along branches,“examining leaves both above and below them; the chickadees sometimes scanned by hanging upside-down.” This makes it easier to find and extract leaf-miners, as the underside of the leaf is easier to tear open than the surface. And in fact this behavior is reflected among other species of chickadee and leaf-miner: “Similarly, in 15 years of study, Connor et al. (1999) never observed species other than Carolina chickadees (Poecile carolinensis) feeding on the larvae of the gracillarid Cameraria hamadryadella [oak leaf miner].” While these are not the same species of leaf miner studied in this paper, the point is that chickadees eat leaf-mining insects. And leaf-miners can obviously adapt to new food sources, including introduced plants. This is basic ecological science.

Oak leaf miner damage

Oak leaf miner (Cameraria hamadryadella)

 

 

 

 

 

 

Neither Craves’s article (the second of these two articles) nor that by Connor et al. (cited within Craves’s article) are cited by Narango et al. (2018 – the first article), even though both are certainly pertinent to the topic. But they don’t fit the narrative – which is that introduced plants are not good food sources for the insects that chickadees eat. So they are left out of the discussion, which by default is now biased – not objective. Not science-based.

And I don’t have a good answer to the obvious question – which is why we continue to demonize noninvasive, introduced plants in the absence of a robust body of evidence supporting that view.

 

Hello Again, and a fun article that was called to my attention.

By Jeff Gillman (posted by Linda C-S, who has taken liberties with using photos from UNC Charlotte gardens that have nothing to do with Jeff’s post.)

Living arch at UNC Charlotte gardens

It has been almost two years since I have had the chance to post anything as a Garden Professor. Since then I’ve taken a job as the Director of UNC Charlotte Botanical Gardens and there are all kinds of things I’d like to share with you, and perhaps sometime over the next few weeks and months I will, but for now what is probably most pertinent is that I absolutely love my job. I am still doing some work on garden myths, but what I’m finding more entertaining is investigating the histories of different plants and their interactions with humans. In fact, in about a month or so, my friend Cindy Proctor and I will be releasing a podcast titled The Plants We Eat that investigates the interesting history, culture and biology of the various plants we use for food. We’ve already recorded shows on strawberries, grapes and mad honey, and we’ll be doing shows on apples, figs, and a few others before we release it – we want to have a decent backlog of shows so that we can maintain a pace of one podcast a week.

UNC Charlotte gardens

But enough about me! The current Gardens Professors called my attention to a recent article titled “The effect of ad hominem attacks on the evaluation of claims promoted by scientists”, and I found it informative to say the least. This article provides instructions on how to stop people from trusting a particular study.

No, seriously. If you wanted to you could actually rewrite this as a short manual on how to make people question the results of any scientific study.

And if you did I think it would look kind of like this:

(Short Disclaimer – I’m pretty sure that the authors of the above article never intended it to be taken in the way I’m presenting it. I’m posting this purely as satire.)

So, someone has published a scientific article that you disagree with. Hey, we’ve all been there. Scientific evidence that contradicts your beliefs/works/preconceived notions sucks, but it isn’t the end of the world. There are things you can do.

You might consider conducting your own well-designed experiments that would call into question some of the claims of the offending work. Once upon a time this was been the standard way to address this kind of problem, but this could take months or even years to accomplish. And the truth of the matter is that your experiment might not even say what you want it to and even if it does, with attention spans the way they are, nobody will even remember what you’re even talking about when your paper comes out.

Which is to say, there are better, faster ways to take care of inconvenient research, and that’s where this convenient manual comes into play.

Rain gardens at UNC Charlotte

First, realize that attacking the research itself isn’t a sure thing. Sure, it’s the right thing to do, but morals be damned, attacking the research itself can be waaaayyy too technical. People won’t understand what you’re talking about, so forget about it.

Attacking researchers personally by making nasty comments about where they graduated from college or that they do sloppy research would seem like winner, that kind of attack just doesn’t cut it today. Maybe it’s the political climate, but, to their credit, people just aren’t responding to non-specific personal attacks the way they once did.

So you’ve got to be smart and hit them where it hurts. You could say that data was fabricated in the paper that you want to discredit, but this could be problematic if it isn’t true. Not to worry. All you really need to do is find an instance where the researcher did do something wrong. In fact, it’s possible that some past misconduct could be even more effective at discrediting a paper than misconduct on the paper in question itself.

The gold standard, however, is conflict of interest. By establishing that the researcher who has caused you grief has some sort of conflict of interest you can cause people to question the results of research just about as effectively as if some sort of misconduct had taken place, and conflicts of interest are much easier to find! You could blame a company, a person, or even a University. Shoot, want to show that a study, which demonstrates that an herbicide is effective at controlling a weed, isn’t true? All you need to do is show that the company which makes the herbicide gave a few hundred dollars to an athletic program at the school, or show that one of the student workers in the lab has a second cousin employed by the company. It’s all good.

Water hyacinth

And so there you have it. The fast, easy way to discredit someone. And remember, just implying things can be as effective as having facts. No need to lie! Good Luck, and remember The Truth is What You Make It!

NON-GMO FERTILIZER?

http://passel.unl.edu/pages/informationmodule.php?idinformationmodule=1057077340&topicorder=3&maxto=14
Image courtesy of Plant & Soil Sciences eLibraryPRO at UNL

I was asked by Dr. Linda Chalker-Scott to look up some information in order to answer a recent comment and question on a previous post.

Paraphrased, the question is, “… are there any verifiable “organic” fertilizers that can be guaranteed to be made from 100 percent non-GMO sources.”

First off, let me state up front that the whole “Non-GMO” labeling effort is pure marketing. There is no evidence to suggest products that come from genetically engineered crops are any different than crops made from other plant breeding methods. The body of evidence in fact suggests they are as safe as their conventional counterparts, and have some excellent benefits to farmers and consumers from an economic and environmental standpoint.

Having gotten that disclosure out of the way, and assuming that price is not a factor, it turned out to be an interesting question to answer.

“USDA Certified Organic” fertilizers would be problematic, since there are exceptions to the organic standards, which allow manures fed GE crops to be used.

Similarly, oilseed meals like cottonseed, soybean meal, etc. also can be certified organic, even though they come from genetically engineered crops.

ALFALFA MEAL

https://commons.wikimedia.org/wiki/File:Lucerna_-_Budaörs.jpg
Alfalfa Field image courtesy of Wikimedia Commons

One possible alternative in that category is alfalfa meal, since genetically engineered alfalfa is currently grown on only 13.5% of alfalfa acreage, whereas in the case of cottonseed, soybean, sugar beet, and corn products, the rate of adoption of genetically engineered crops is well over 90% of U.S. acreage.

Only about 13.5 percent of harvested U.S. alfalfa acreage is genetically modified, compared to more than 90 percent of corn, soybeans, cotton, canola and sugar beets acres, according to a new USDA report that cites 2013 farmer surveys.

It appears likely the percentage of genetically engineered alfalfa will continue rising, though: Roughly one-third of newly seeded acreage planted that year was of a biotech variety resistant to glyphosate herbicides, USDA said.

Farmers have been slower to adopt genetically engineered alfalfa partly because it’s a perennial crop that stays in the ground for roughly five years, said Dan Putnam, an alfalfa extension specialist at the University of California-Davis.

It would be incumbent upon the buyer to ask, however, if the alfalfa meal came from a grower who does not use genetically engineered alfalfa, and whether or not the supplier of the alfalfa meal guarantees that.

MANURES FROM LIVESTOCK FED ONLY ORGANIC FORAGE

https://commons.wikimedia.org/wiki/File:Hestemøj.jpg
Manure, a field in Randers in Denmark. Image courtesy of Malene Thyssen at Wikimedia Commons

“Demeter USA” … the private certifying entity that guarantees “Biodyamic” preparations does require that any manures come from livestock fed only “USDA Certified Organic” feed. So manures that carry that seal should satisfy the question.

As an aside, here is Dr. Linda Chalker-Scott’s literature review of “Biodynamics” and why that certification has little science to recommend it.

Further, finding the product would be difficult, since it is primarily produced on-site at certified Biodyamic farms, and used there.

SEAWEED FERTILIZERS

https://commons.wikimedia.org/wiki/File:KelpforestI2500ppx.JPG
An underwater shot of a kelp forest. Image courtesy of Wikimedia Commons

Next products that might qualify are seaweed, or kelp products. There are no genetically engineered seaweed/kelp products I’m aware of. However, there are real concerns about the sustainability of harvesting seaweed and kelp from the wild.

Dr. Linda Chalker-Scott wrote about them here:

The ecological impacts of increased seaweed harvesting are currently under investigation and the possibility of significant ecosystem damage is real.

There is however, some interesting research and startup companies that are farming seaweed and kelp for a variety of potential uses.

I can’t however, find any products available for the home gardener that are sourced from this effort. Still early.

So, when it comes to seaweed/kelp products, you’ll have to (again) ask a reputable supplier to answer the “sustainable” question.

BAT GUANO

https://en.wikipedia.org/wiki/Bat_Cave_mine
Bat Cave Mine Image courtesy of Wikimedia Commons

In a similar vein, “Bat guano” products would also qualify as “non-genetically engineered”, but the sustainability question also comes into play. How is it harvested? 

I can’t deny that it’s a great fertilizer, but if you want to use an organic fertilizer why not at least consider one that is renewable instead of one that is from a limited resource and which may cause harm to a unique ecological system?

SEAFOOD BY-PRODUCTS

https://commons.wikimedia.org/wiki/File:PSM_V45_D079_Non_edible_fish_scrap_processing.jpg
Non edible fish scrap processing … Public Domain image from 1894

Fertilizers made from by-products of the seafood and fish industries, assuming they don’t come from aquaculture farms, since the livestock feed for those operations could be sourced from genetically engineered crops, do have a history.

Two links (there may be others, but these seem sufficient for now), a comprehensive review of products (including fertilizers) from the Alaska seafood industry, put together by Oregon State University

Fish Fertilizer Product Descriptions

Fertilizers are characterized by their Nitrogen-Phosphorous-Potassium content (N-P-K). Therefore all fish material will have some fertilizer value since fish contain protein which is Nitrogen,
the bone contains Phosphorous and the flesh and bone contain Potassium. Generally, fish products are re-allocated to fertilizer use for any number of reasons including quality too poor for feeding, volume too small to convert to fishmeal and oil, and an available agricultural market in the vicinity of the waste material.

And a similar document put together by Michigan State University about the use of fish by-products for other uses.

In an effort to help the Michigan fish processing industry find better solutions to handle fish processing waste materials, a project was initiated to determine the viability of composting fish waste.

CHILEAN NITRATE

https://commons.wikimedia.org/wiki/File:Dusičnan_sodný.JPG
Mined Sodium Nitrate (NaNO3) Image courtesy of Wikimedia commons

There is a mineral product called Chilean Nitrate or Nitrate of Soda that is mined from a desert in northern Chile that is allowable for use under the standards for organic production in the U.S. However, it is not allowed for use under Canadian, or international organic standards, and a change to prevent its use under U.S. standards is still pending. Up until 2012, this was the wording for its use.

Sodium nitrate, also known as chilean nitrate, cannot account for more than 20 percent of the N requirements of organic crops in the United States.

Its use is also prohibited by the International Federation of Organic Agriculture Movements (IFOAM) and most other standards for organic production outside the United States.

After 2012, the 20% restriction was dropped in the U.S.

The expiration of the current notation will effectively mean that sodium nitrate may be used in organic crop production without a specific restriction on the amount used: however, producers must continue to comply with all requirements of the soil fertility and crop nutrient management practice standard.

Although the National Organic Standards Board (NOSB) recommended that sodium nitrate become a completely prohibited nonsynthetic substance, the NOP has not issued rule-making to carry out this recommendation as of yet.

FEATHER MEAL

A by-product of the poultry industry.  Is it from poultry fed only non-GMO feed?

LOCALLY PRODUCED

The final piece of the puzzle can be found (only partly in jest) in Dr. Jeff Gillman’s post about a cheap, locally available source of Nitrogen.

You’d be saving yourself the cost of fertilizer, saving the environmental cost of shipping the fertilizer you might otherwise purchase, saving water, and you’d have something unique to tell your gardening friends about.  Win – win situation as far as I’m concerned.

In summary, I don’t buy into any of the fear-based marketing of products that come from genetic engineering. There may be (at this time) sources of alfalfa meal that do not come from genetically engineered sources.

Biodynamic manures certified by Demeter USA require that the animals be fed only “USDA Certified Organic” feed, but will be difficult to come by. Seaweed/Kelp and Bat guano products would qualify, but have major sustainability questions about them. Lots of potential with seafood/fish by products, and finally … a personal possible solution.

Many thanks to Emanuel Farrow, a consultant to both conventional and organic farmers, who helped point me in the right direction and provided important fact checking expertise for this post.

Our New Year’s Resolution – to keep you informed and entertained every week.

Happy New Year!

The Garden Professor’s collective resolution is to have at least one new blog post a week for 2018. So I’m kicking things off with a little fact checking on the claims made for a product that’s “a complete ecosystem in a bottle.” The company touts its strong connection to science (“our products revolve around biology”). There is a long list of ingredients and claims – way too much for one post. We’ll start with the first four this week.

All this can be yours if the price is right!

Ingredient claim #1: “Chitin/chitin degrading Bacillus: Chitin is a natural polymer that is found in crustaceans, such as crabs, lobsters, shrimp and oysters as well as other organisms, such as insects, worms and fungi. When added to the soil ecosystem, chitin (also referred to as chitosan) promotes the growth of chitin-degrading bacteria. These bacteria, in turn, create a hostile environment for pathogenic fungi and parasitic nematodes. Chitin also acts directly on plants to promote tissue repair and disease resistance.”

Fact check #1: A couple of technical points: oysters don’t have chitin. And they’re not crustaceans. They are MOLLUSKS. They have shells with CALCIUM. And chitosan is not the same thing as chitin. It’s an industrially produced material that comes from chitin.

Not a crustacean.

Chitin is indeed found in arthropods, which include crustaceans and insects. Now, most of us don’t have crabs, lobsters and shrimp roaming our landscape, but we do have insects. Lots of them. They produce a lot of chitin when they molt and when they die. Do you really think we need to add more chitin for Bacillus to consumer? I sure haven’t seen any science supporting that practice.

What about the Bacillus species that degrade chitin? Well, if you’ve got insects in your landscape, you can bet you’ve got microbes that break down chitin as well. Otherwise you’d be up to your garden boots in chitin carcasses. So why do we need to add more bacteria?

Imagine billions of these in your garden…

Finally, there’s no evidence that chitin applied to plants in the landscape has any effect whatsoever. You might get responses in the lab, and chitosan (not chitin) might have some direct application. But like many other elicitors, you have to get it inside the plant to have a cellular effect. And plants are particularly adept at keeping things like decomposing bug bits outside of their tissues.

Ingredient claim #2: “Compost tea: The disease suppressive characteristics of compost have long been known and therefore the liquid extracts from compost, known as compost teas are being use to battle plant disease while stimulating plant growth. Beneficial organisms including bacteria (primarily from the genera Bacillus, Pseudomonas, and Penicillium) along with some yeast and fungi form a physical barrier against disease causing agents and provide a competitive environment in which the pathogenic species lose out. In addition, compost teas stimulate plant growth, translating into a healthier plant, which is more resistant to attack from disease. Compost teas have shown effectiveness in the control of late blight, grey mold, downy and powdery mildew, fusarium wilt, and apple scab among many others.”

The visuals are more interesting than the product.

Fact check #2. Just because compost has disease suppressing characteristics doesn’t mean that water leaching through it will have the same. We’ve been hearing for years that compost tea suppresses disease. Where’s the definitive research? It’s a topic I’ve been following for nearly two decades and there’s still nothing that’s consistently effective. (Another technical point here: it’s illegal to make pesticidal claims of a product that’s not registered for that use. Company lawyers may want to review that.)

There are many species of bacteria, including the ones mentioned, that form protective and beneficial biofilms on plant tissues such as fine roots. You can find these bacteria in compost and other sources of organic material – that’s their food source. You won’t find many of them in compost tea.

I’d love to see evidence of anything stimulating plant growth other than plant growth regulators (or hormones as they’re sometimes called).

Aren’t marketers getting tired of compost teas yet? I’m getting tired of hearing about them. I reviewed the science about them 10 years ago and haven’t seen anything to warrant an update.

Ingredient claim #3: “Essential oils: or essences they are called, are highly concentrated substances extracted from various parts of aromatic plants and trees. Essential oils are combined with other carrier oils and teas for stabilization. Essential oils are used against plant pests and disease by interfering with their reproduction and feeding habits while protecting beneficial predatory organisms.”

We like them, ergo they work.

Fact check #3: Essential oils have no documented benefit when applied outdoors. They can be effective in closed spaces, like homes and greenhouses, but they dissipate quickly outside. What I really want to see, however, is the mechanism by which oils can identify – and actually protect! – beneficial insects while killing pests. (Hey, lawyers…we’ve got another pesticidal claim here…)

Ingredient claim #4: “Streptomyces griseoviridis: Is a naturally occurring soil bacteria. The microbe deprives pathogenic fungi of living space and nourishment by colonizing roots in advance of fungi. In addition the microbe secretes various enzymes and metabolites which inhibit pathogenic growth. Streptomyces griseoviridis has been shown to promote the growth and yield of all plants. Streptomyces griseoviridis is used for the prevention of root and stem rot, Pythium, Rhizoctonia, Helminthosporium, Sclerotinia, among others.”

All those stickers keep the bad guys from colonizing.

Fact check #4: While this is a naturally occurring soil bacterium, it’s not clear where it naturally occurs. EPA information states it was first isolated in Finland from peat bogs. Is this something we should be introducing to our own soils? Its effectiveness in disease control and plant performance is sporadic and confined primarily to greenhouse application on crop plants. The diseases listed are common in greenhouses, but not necessarily in gardens and landscapes (presumably because there are natural controls outdoors in healthy soils). There is certainly nothing to support its use in gardens and landscapes, especially considering that many native, beneficial bacterial species can colonize plant roots and act as a protective biofilm.

Stay tuned for next time!

Dowsing for dollars

Recently I was at the Northwest Flower and Garden show and spoke to a gardener who was excited about some new information from his garden club meeting. Their speaker was a dowser – who promotes dowse gardening.

Traditional dowsing for water

Now this was a new concept for me. I’ve heard of dowsing, of course, in the context of finding underground water. But dowse gardening?

Fortunately, my gardening friend shared his handout with me. I did a little Internet sleuthing and found the author, whose goal was to combine her two interests: dowsing and gardening. In a 2003 column, she stated “My main focus is ways of using subtle energy to get good crops or gardens.”

For me, this was an immediate red flag. It’s very much like the author’s motivation in The Sound of Music and Plants. Searching for a topic for an undergraduate research topic, she asked “What in the world can I do with music and plants?” Trying to force two unrelated subjects together without preliminary data to suggest the pairing is not a logical approach to scientific inquiry.

Anyway. Back to dowse gardening. It would take me weeks to dissect all of the claims made in the handout. In brief, the presentation explains how to find energy, how to receive and broadcast energy, and how to use “subtle energy” to grow healthier plants and control pests.

This circle garden just looks sad and lonely.

Unfortunately, the specifics on exactly how this happens were not given. But attendees were advised to create circle gardens (they are energy outgoing), to use earth energies to determine where and where not to grow plants, and to use prayers and crystals to improve seed sprouting. At least in this last case there were data:

“Prayers over seeds -30% increase in sprouting and production – energy! Next step – crystals pointed at sprouting seeds, 50% increase in sprouting and production – energy!”

And finally, there were all kinds of products that were recommended, including

  • French coils for “inducing beneficial energies in trees and larger perennials”
  • Energized water made by a process “that can transform our banal tap water back to its natural potent state as the elixir of life”
  • Sonic Bloom – an “organic fertilizer applied with sound”
  • Slim Spurling’s Light Life Tools which “support the work of environmental clearing, air pollution clearing, energy balancing, water improvement, alternative agriculture methods, insect control without sprays, beneficial insect enhancement, alternative health methods, personal self-care, computer radiation reduction, EMF pollution reduction, personal life improvement as well as business improvement”
  • Intrinsic Data Field Analyzer – “a consciousness interactive instrument that has been used experimentally to detect and balance the IDFs of plants, animals, minerals, and virtually all animate and inanimate objects”

What you’ll need to detect subtle energy

As a scientist, it’s easy for me to discount all of this as silliness. But the fact remains that many people, including gardeners, long for mystical approaches to life. And unfortunately there are always going to be hucksters waiting to take advantage of that longing.