Category: Uncategorized

Plastic grass and organic gardens

One of the best cures for writers’ block for a Garden Professors is to spend a little time in front of the tube watching home gardening shows.  Now, to be sure, there are useful nuggets of information that can be gleamed from an hour or so of gardening or landscaping on HGTV or PBS Create.  But there are moments when I just stare at the TV in disbelief and go, ‘Have these people lost their frickin’ minds?’

 

A recent case in point, a half-hour gardening show devoted to installing an ‘allergy free’ backyard for a youngster, we’ll call him Billy, with environmental allergies.  Let me state up front I am in no way minimizing the seriousness of environmental and related allergies.  I suffer wicked seasonal allergies (yes, I know, poor career choice) and I have several close friends whose children have severe allergies.  I realize allergies can seriously affect quality of life and, in the cases of some food and insect allergies, can be a matter of life or death.  And I realize that a parent will do just about anything to keep their kid healthy.  Nevertheless, some of the practices promoted on this show strained all manner of credibility.

 

First, since Billy is allergic to grass, the landscaper replaced all of the grass in the backyard with synthetic turf.  Grass allergies are among the most common allergies but what is it about grass that most people are allergic to?  Pollen.  According the National Institutes of Health just keeping grass mowed is a simple preventative measure to reduce grass pollen.  Synthetic grass may have issues of its own with molds and there are remaining uncertainties regarding the safety of the used-tire derived crumb rubber used in some fake turf.   And if Billy has issues with pollen, I saw a much bigger problem looming like an 800 lb gorilla as the camera panned back from the picture-perfect synthetic lawn: Trees, specifically dozens of oaks and pines in the woodlots beyond the backyard.  I joined the show part way through but the overall landscape looked like the Southeast, perhaps Georgia or the Carolinas.  Even if the fake turf does reduce grass pollen in the back yard, Billy will scarcely notice as a yellow-green cloud of tree pollen envelops his house every spring.

 

Next, in addition to wanting a place to play, Billy wanted a vegetable garden.  Actually, given Billy’s obvious disinterest during this part of the show I don’t think he was really that interested in vegetables but the producers knew they couldn’t fill a 30 minute show with just fake turf.  Assuming Billy really was into vegetables the solution, of course, was an organic garden.  Why an organic garden is a panacea for allergy sufferers was never explained in the show; apparently pollens and molds don’t hang out in organic gardens.  The choice of vegetables was curious as well.  Billy got to plant squash and watermelons; guess no one bothered to tell Billy that cucurbit allergies are among the most common food allergies for people predisposed to pollen allergies.  For good measure, Billy got to plant some corn – doubt that could ever produce any pollen…

 

Bottom-line: take the info from the garden shows with a grain of salt and consider the source of the information.  Often times these shows are limited to whatever local source they could dredge up.  Do you really want to rely on a landscape contractor to make decisions about your child’s allergies and health?  Enjoy the shows but keep your skepticism handy and be ready to do some fact checking on your own.

Compost tea…again

My not-fan Justin has emailed me again with some more substantial comments of my criticisms of compost tea.  I’ve posted his email here, along with my responses in a point-counterpoint format:

1.  “Compost teas do vary from batch to batch, the same way galaxies vary.  Without the complexity and biodiversity present in the tea, you might as well just be using water.”

Yes, they do vary, and this is why it is so difficult to conduct replicated and repeatable studies on the efficacy of compost tea.  The comparison to variability in galaxies is really not relevant, nor is it conducive to experimentation.

2.  “Generally speaking though, this can be overcome by the purchase of virtually any microscope capable of achieving 400x field of vision or greater. By looking at what is present in the tea and a little bit of background knowledge, one can make an educated decision as to whether or not it will improve conditions on one’s plants and soil.”

Purchasing a microscope does not overcome variability.  Furthermore, microbial species can’t be reliably identified simply by looking at them under a microscope.  The “little bit of background knowledge” is vague.  What, exactly, will help in making the “educated decision” in whether it will do any good to use it?

3.  “I assume that these steps were not taken in these experiments, because of the generally lacking method in what has been come to be labeled (tobacco science).”

The steps referred to (I assume in point 2) are not useful in assessing efficacy of a product – in other words, demonstrating an effect not seen in the control treatment.  What would be the control?  Not looking under a microscope?  Not having background knowledge?  An experiment requires experimental variables.  I hadn’t heard of  “tobacco science” and had to look it up.  Apparently it’s “science that is skewed or biased, especially toward a particular industry.”  The only industry I see in this discussion is the compost tea industry – and yes, it’s an industry.

4.  “First of all you are trying to disprove compost tea as a foliar pesticide only. You do not do a relatively new science justice by not looking at the wholeness. Any and all foliar applied pesticides are palliative in nature, and symptoms will recur if you do not deal with the source problem. Compost tea (aerated) is to be used in the rhizosphere first, foliage second, and surrounding environment third. If you are not talking about this mode of application, you are not talking about compost tea.”

Compost tea is not a new science.  It is a product.  To demonstrate efficacy of a product requires conducting a controlled experiment in which there are one or a few variables.  It’s not possible for science to look at the “wholeness” of compost tea – it has to be looked at systematically.  Neither is compost tea defined by its mode of application.

I do agree with Justin, however, that symptoms (of disease or whatever) will recur if the underlying problem isn’t addressed.  There are scientifically testable, consistently reliable methods for improving soil health and plant health. At this point, compost tea is not one of them.

5.  “In order to disprove compost tea, you must first explain to the reader how balances of microbial life (bacteria, fungi, protozoa, nematodes, microarthropods, earthworms) are different in various stages of ecological succession. You must describe how the OVERALL HEALTH of any plant depends on how it has evolved to live in the soil conditions in which it is planted. You must describe how human activity effects soil food webs and how soil disturbed or treated with substances toxic to microbial life will move the soil backwards in succession. This will create a soil that favors weeds over crops by reverting the soil to bacterial dominance.”

Disproving any hypothesis (e.g. “compost tea prevents foliar disease) relies upon scientific evidence.  What Justin is asking for is not experimental but explanatory.  (There are several inaccuracies in what he outlines above, but in the interest of sticking to one topic I’m ignoring them.)

6.  “If you are going to debate compost tea you must disprove its ability to create a more fungal soil and inoculate the rhizoshpere with arbuscular mycorrhizae, improving soil born nitrogen. Excuse me, soil born proteins in the form of microbial biomass that are released as ammonium or nitrates in detritus, when consumed by predatory microbes, that are generally found to be lacking in human disturbed soils.”

The first point is incorrect, and is one of the hallmarks of pseudoscience – reversed burden of proof.  It is up to proponents of compost tea – or any other product or practice – to demonstrate efficacy.  (Wikipedia has an excellent overview of the characteristics of pseudoscience.)

7.  “You must prove: that most garden or Ag soils have a stable food web, the food web is not necessary, or that compost tea does not create a more complete food web. You must create a fair experiment (not paid for by cargill) that tests foliar applications on crops planted into a healthy rhizosphere with a complete food web.”

No.  Compost tea proponents must demonstrate that compost tea has an effect.  Period.  (It’s also important to understand that science doesn’t “prove” anything.  It either supports a hypothesis or disproves it.  That’s why scientific inquiry is a dynamic process – you never know when new evidence will lead to a paradigm shift.)

8.  “If you cannot present your findings in this way, you are misleading your readers knowingly. I was raised to classify that as a lie.”

I don’t conduct these compost tea experiments (though I do conduct research in other areas).  Part of my job as an extension educator is to read the scientific literature and translate it for use by nonscientists.  I have posted an extensive bibliography of the compost tea literature on my web site.  If I were either deliberately or accidentally misleading anyone, I would be in serious trouble with my university.  Given that I started my criticism of compost tea on my web site over 10 years ago, it’s likely that the information is not misleading.

Fan mail…NOT!

Below is an email I received this morning.  I’ve apparently made Justin really angry.  So as he’s requested, I’m giving him the chance to debate me.

"LISTEN HERE DR. FACE

Who owns you Dr. Linda Chalker-Scott?

You are a cheap mouthpiece and I don’t believe a word that you say. I’d debate you right under the table.
Any day, Lady.

Why don’t you just bring it on sister girl and first describe how vegetation thrived on this planet for millions of years before the phony baloney chemical crap that you use.

Even if your understanding of chemistry and physics is spot on about sprayed on nitrogen being identical to that in nature, it is unsustainable, it leaches, it costs more to the HORTICULTURIST than simple crop rotating methods. These chemicals disrupt the soil FOOD WEB; are you an ecologist? Are you a biologist?

All you are is a tart mouthpiece for the money monsters. This mail probably goes straight to the corporate lawyers that put those ugly lies in your mouth.
Compost can save the world; but you won’t let it, because it won’t pay for your next elective surgery."

So Justin, here’s your chance to air your complaint.  Let me know exactly what I’ve written that you disagree with and I’ll explain my position.  But keep it civil and keep personal comments out of it.

Permaculture – my final thoughts

We’ve had some good, vigorous discussion about permaculture, specifically around the book Gaia’s Garden.  I’ve pointed out some problems with the author’s understanding of relevant plant and soil sciences and will wrap up this week with a look at the glossary and bibliography.

Glossary

The glossary contains a number of scientific-sounding words and phrases with unscientific definitions; for example:

“Buffer plants: Plants placed between guilds or between allelopathic species. They should be compatible with the trees in each guild and should have a positive effect on one or both of the guilds to be linked.” (“Buffer plants” is a phrase legitimately used in ecological restoration where plantings separate wetlands or other natural areas from human activity.)

“Guild: A harmoniously interwoven group of plants and animals, often centered around one major species, that benefits humans while creating habitat.” (The term “guild” is ecological and refers to groups of species that exploit the same types of resources.  It has been hijacked and redefined for permaculture.)

“Narcissistic: Plants that thrive on the leaf litter of members of their own family, such as the Solanaceae, or nightshade family.” (In this case, this is an unscientific term given a scientific-sounding – but nonsensical – definition.)

“Polycultures: Dynamic, self-organizing plant communities composed of several to many species.” (Polyculture is an agricultural term referring to the planting of multiple crops. It’s a cultural strategy in Integrated Pest Management.)

“Sectors: Areas where outside energies such as wind, sun, fire and so forth enter a site. These energies can be mitigated, captured, or otherwise influenced by placement of elements in the design.”

Bibliography

There are only two books I would consider scientific; one soils textbook from 1996 and the other is Odum’s classic text Fundamentals of Ecology (1971). I’m disappointed in how scarce and dated these references are, given the wealth of more recent articles and books that are both relevant to urban gardens and scientifically sound.

The bibliography also includes many books on design and I’m not including them in this critique. Of those that remain, the bulk are nonscientific and in many cases pseudoscientific. Examples of the latter include The Albrecht Papers (Albrecht, 1996), Weeds and What They Tell (Pfeiffer, 1981).

And this last criticism embodies what permeates much of Gaia’s Garden: pseudoscience. In the glossary, we see scientific-sounding terms or definitions that are ultimately meaningless or incorrect. Furthermore, we see scientifically legitimate terms such as guild used incorrectly. Both of these practices are characteristics of a pseudoscience.

I think this is unfortunate. I’ve mentioned before that I agree with much of the philosophy behind permaculture. But dressing up this philosophy as science both misleads nonexperts and alienates scientists.

So here’s a challenge – why not write a new book on permaculture and collaborate with a scientist? (I know a few who are writers!)

Building a Better Container

As most of you know, roots circling around a container isn’t considered a good thing.  And so people try various things to control circling roots.  One of the more creative horticultural minds out there, Carl Whitcomb, a guy why basically got sick of academia and went into private industry (and, as far as I can tell, loathes peer review and the whole process of publication), decided to see what he could do about making containers that don’t encourage circling roots.  He came up with a number of designs, but my favorite is the RootTrapper.  The container is made of a flexible cloth which roots get lodged in, preventing them from circling.  Not that I’ve never seen a circling root in a RootTrapper, it’s just that these circling roots are extremely rare.


A row of elms in RootTrappers


A cut open RootTrapper

This is one of those innovative products that really works and it surprises me that so few people use this growing system.  Yes, it’s a bit more expensive than standard containers, and yes, it does take a little more effort to take the tree out of this container than a smooth sided one.  But man, I’ve never seen a better root system come out of a container than those which you get out of these.

Permaculture – the discussion continues

We’ve started a robust discussion on the topic of permaculture, especially as applied to home gardens.  Let’s continue looking at some of the advice provided in Gaia’s Garden targeted towards home gardeners.

The book contains several lists of plants suggested for specific functions.  For brevity’s sake, I’ll just mention two:

“Host plants for Beneficial Insects” (pp. 157-159)
This list is prefaced in the text with “many of these florae are very attractive and can (and should!) be included even in the most formal garden bed.”  With this strong endorsement, the author then presents an unsourced list of plants, several of which are identified as noxious weeds in many states in the country.  They include Washington noxious weeds false indigo (Amorpha fruticosa), fennel (Foeniculum vulgare), Queen Anne’s lace (Daucus carota), toadflax (Linaria vulgaris), cinquefoil (Potentilla recta), sulfur groundsel (Senecio vulgare), and tansy (Tanacetum vulgare).

“Dynamic Nutrient Accumulators” (pp. 131-134)
We are told “certain species draw specific nutrients from deep in the soil and concentrate them in their leaves” and given an extensive table of these plants and exactly which nutrients they accumulate. The references for this table are not scientific, and in at least two cases are mystical in nature (Cocannouer’s Weeds: Guardians of the Soil and Pfeiffer’s Weeds and What They Tell).  As in the previous table, many of these plants are designated noxious weeds in Washington or other states and include nodding thistle (Carduus nutans), Canada thistle (Cirsium arvense), fennel (Foeniculum vulgare), toadflax (Linaria vulgaris), creeping thistle (Sonchus arvense), and tansy (Tanacetum vulgare).

As readers of this blog know by now, we GPs are not “plant purists.”  But it is highly irresponsible to encourage people to plant listed noxious weeds in their gardens.  Even the author seems to understand this, and states (on page 15) that “it is foolish to deliberately introduce a species known to be locally opportunistic.”  It’s mystifying, then, that he does exactly that in these two tables.

The inclusion of the table of “dynamic nutrient accumulators” demonstrates that this book tends to wander far afield of the philosophical roots of permaculture.  It is an excellent example of pseudoscience, as it creates a scientific-sounding phrase (“dynamic nutrient accumulator”) and misleads non-experts into believing a scientific claim (nutrient accumulation of specific minerals) without providing actual supporting data.

Everything is obvious once somebody shows you…

It’s amazing how many things in life seem complex when we try to figure them out for ourselves but then we end up smacking ourselves on the forehead when someone shows us how simple it really is.  The infield fly rule comes to mind.  Some colleagues of mine here at Michigan State may be on their way to such a solution for the problem of white grubs in lawns.  Drs. Dave Smitley (Entomology), Kurt Steinke, and Trey Rogers (Crop and Soil Science) are investigating the effect of mower height on turf damage from grubs.

European chafer grub.  Photo: David Smitley

The premise is simple: White grubs damage turf when they consume about 75% of the turf roots present.  Raising the mowing height of most standard mowers from 2” to the highest setting (usually 3 ½”) also results in more root growth; often by more than double.  Since there’s a limit to how much root mass grubs can consume, increasing the amount of roots ensures the damage threshold is never reached.  The working hypothesis has been confirmed by greenhouse tests and now the researchers are taking to the field.


Chafer grub damage.  Photo: David Smitley

This may turn out to be another example of how raising mower height and not trying to make your lawn look like a golf course fairway can reduce inputs and keep your turf healthier.

Some Super-Cool Stuff

For the past ten years or so I’ve worked to try to transfer information about horticulture to people.  It sounds simple, but it actually took a lot of time and effort to figure out the best way to do it, and I’m still not there yet — and probably never will be.  The reason that I mention this is because I appreciate it when another horticulturist, such as my fellow garden professors, work to get information about horticulture out to the public.  So yesterday we had a speaker come to our depoartment to give our annual end of the year lecture — It’s kind of a big deal for us — We usually have a big name person (horticulturally speaking of course) and pay him or her pretty well and have a reception.  It’s nice.  We also hand out scholarships to our undergraduates who earned them and any awards which we have to give.  But anyway, back to the speaker.  This year we had a guy come in who I’d never heard of before besides some strong recommendations from some of my colleagues here in the department.  I also did a cursory check of his website.  I liked what I saw, but I wasn’t blown away.  Sometimes I’m such a dingbat.  Simply put, this guy gave one of the top two or three horticultural (actually I should say botanical — it’s more botany than horticulture) presentations which I have seen.  His name is Roger Hangarter and he is a professor at Indiana University.  In a nutshell he films plant’s moving using time-lapse photography to demonstrate important concepts.  Here is one of his websites:

http://plantsinmotion.bio.indiana.edu/plantmotion/starthere.html

But if you do a google search for him he has a lot of other things on different sites.  He has even created a traveling display for museums called slowlife.  Very, very cool.  There aren’t a lot of people who I’m in awe of — but this guy is one of them.  If you have a garden club or run a master gardener program you NEED to get this guy on your calendar if you can.

Permaculture – beginning a discussion

Among other things, part of my job involves reviewing educational materials for use in WSU’s Extension programs related to urban horticulture.  One of the books is “Gaia’s Garden: a guide to home-scale permaculture” (T. Hemenway).  It occurred to me that my review might also be of interest to our GP readers.

I’ve created a fairly extensive review and I will break it into separate posts over the next few weeks.  So let’s start the discussion off with a topic we already know is inflammatory:  invasive species.  To be clear, we are not talking about the many introduced species, plants and animals alike, who appear to be well-behaved in our country.  Here’s my take on “The Natives versus Exotics Debate” (pp. 12-17):

The author, with no formal training in biology past his bachelor’s degree, states that “calling a species ‘invasive’ is not good science.”  This will come as news to researchers in the field of invasion biology.  He blithely disregards the real environmental and economic damage caused by invasive species and erroneously believes that invasive species selectively appear only as a result of human-caused environmental disturbance.  Apparently natural disturbances (from fire, volcanic eruption, flooding, etc.) don’t open themselves up for invasion (again, a notion that is incorrect and refuted by a number of obvious examples, such as the 1988 zebra mussel invasion of Lake St. Clair and the subsequent colonization of many freshwater habitats).   The author seems not to understand that there may be unfilled niches in certain ecosystems that can be exploited by invasives, endangering native species whose niches may overlap; there are obvious lessons from Hawaii, Australia, and other parts of the world.  In any case, the author’s naive tolerance of invasive species is a poor example to follow and certainly not based on current, mainstream science.

So, fans of permaculture, what do you think?  If permaculture is a legitimate science-based practice, how do we reconcile the very real issue of invasive species?  If you disagree with me, keep in mind one of the hallmarks of pseudoscience: attacking the motives or character of anyone who questions the claims. The arguments should contain content, not insults.

Call for “visiting professors”

I’ll be posting my usual blog later today…but in the meantime we’ve got an invitation for you.

Are you, or someone else you know, a "Garden Professor?"  In other words, do you use current, relevant plant and soil sciences to inform yourself and others?  If so, we invite you to submit a guest posting to our blog.   

We’ll post your article without editing, though we may make comments. 

If you’d like, send a photograph of yourself and any other illustrations you want posted along with your blog. 

We can’t offer any compensation other than the glory of being an online Garden Professor – but isn’t that enough?  We think so!

If you or someone else you know is interested, please contact one of us directly.  My email is lindacs@wsu.edu.