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Teaming with Microbes – In-depth Book Review

Teaming with Microbes, a Gardener’s Guide to the Soil Food Web, is a fairly popular book in the gardening community and I thought it was time to do a review. This book is written by Jeff Lowenfels, a garden writer and attorney, and Wyne Lewis a lifelong gardener. Both gardeners clearly follow the teachings of Dr. Ingham and her soil food web. They have adopted her methodologies and present the ideas in this book.

Teaming with Microbes, A Gardener's Guide to the Soil Food Web

Teaming with Microbes, A Gardener’s Guide to the Soil Food Web

Teaming with Microbes – Overview

The book is divided into two parts. The first part is a primer about soil and soil organisms. The second part takes the information in part one and turns it into practicable action items that a gardener can follow.

Part one 0f Teaming with Microbes gives a very good introduction to the various life forms in the garden including bacteria, fungi, nematodes, protozoa and dew worms, to name the main players. The material is will organized and easy to read by the average gardener. From a biology point of view the material is factually correct and interesting without being too heavy on the science.

The authors also discuss some of the chemistry going on in the soil. For example they discuss the importance of pH, and the conversion of different forms of nitrogen.  Unfortunately, some of the chemical descriptions are misleading or  incorrect.

The second section discusses action items using 19 simple rules for the gardener to follow. In summary the rules use the application of compost, mulch and compost tea to improve the soil food web. All three methods are very well explained in the book. Compost and mulch are accepted scientific methods for improving soil and plant health. Compost tea is not.

For the most part Teaming with Microbes supports the teachings of Dr. Ingham and the soil food web. One exception is the section on using a microscope to identify microbes, where the authors say “when it comes to the microorganisms, we will be the first to admit that you will not be able to determine precisely what is in your soil, even with a powerful microscope.“ (ref 1). The book clearly downplays the importance of counting different kinds of microbes. This is the same conclusion I reached in Soil Bacteria – The Myth of Identification and Management, and goes against Dr. Ingham’s strong promotion of using the microscope to evaluate your soil.

Teaming with Microbes has played an important role in educating gardeners about soil, and the importance of microbes. The authors deserve a lot of credit for this accomplishment. It does a good job of explaining the high level concepts of the soil food web even if some of the details are not completely correct.

I think the book is quite good as an introduction to the food soil web and microorganisms. The inclusion of compost tea is unfortunate, and the emphasis on the importance of adding microbes to the soil limits the value of the book, in my opinion.

I recommend that gardeners read the book with an understanding that some of the claims are not supported by science and that some of the facts are incorrect.

Key Concepts

Teaming with Microbes follows most of the key concepts of Dr. Ingham’s soil food web program. The rest of this post will briefly discuss these concepts and provide an overview of the issues.

This post will be followed up by two additional posts that will look more closely at some details in the book.

Synthetic Fertilizers and Pesticides Kill All Microbes

This is repeated throughout the book and forms one of the key reasons why you need to follow the 12 steps to start building your soil food web from scratch. As proof they say “what gardener has not seen what table salt does to a slug”.

Pouring high concentrations of salt onto a slug is nothing like putting fertilizer on the soil. The pesticides and fertilizers will dissolve in water and flow through the soil as a diluted liquid – not a solid.

In the scientific community it is accepted that synthetic fertilizers and pesticides, when used in appropriate amounts do not kill all the soil microbes. I am not saying that some chemicals might have a temporary negative effect on some microbes, but the idea that all or even most are killed by adding fertilizer or pesticides is completely without merit.

Adding Microbes Increases Diversity

This is not supported by science for most most home gardens. Science does not understand the diversity in soil since the majority of organisms have not even been identified. If you don’t know what is there or what is being added – how can you say that diversity is being increased or that there was a lack of diversity before you added the microbes? We don’t know enough about soil organisms to make such claims.

The method proposed in the book for increasing diversity is to take plant material from your garden, compost it, and then return it back to the same garden. So you are taking the microbes that already exist in your garden and returning them back to your garden. How does that increase diversity? If you really wanted to try to increase diversity you would at least get your plant material from another location.

The authors seem to miss the fact that their actions, adding compost and mulching, are really feeding the existing local populations of microbes and as a result plants do better. It is the feeding of existing microbes that is important, not the addition of more.

Different Plants Need Different Amounts of Fungi in the Soil

The advice given is as follows. Perennials, trees and shrubs prefer fungal dominated soil. The fungus makes soil acidic and produces a high ammonium to nitrate ratio. Annuals, vegetables and grasses prefer bacterial dominated soil. Bacteria make the soil alkaline and create a low ammonium to nitrate ratio. Bacteria convert the ammonium to nitrate which is what this group of plants wants. Interestingly, what Dr. Ingham says in one of her YouTube videos (ref 2) is that weeds require a bacterial dominated soil, vegetables need some fungus, with potatoes for example, needing a balance of both. Grasses also need a balance of both, and perennials and trees prefer a fungal environment. Dr. Ingham clearly does not agree with the book.

Does the advice in the book make sense? Similar plants in the same genus can be either perennial or annual – I doubt their biochemisty is so different that they prefer completely different microbes and pH levels in their soil. Our local soil is alkaline, which according to the book, means that trees will not grow well here. But we have lots of forests? We either have unusual trees or the information in the book is not correct.

Most plants can use both nitrate and ammonium, although they might prefer one over the other and some plants don’t do well at the extremes of only nitrate or only ammonium. The term ‘prefer’, in the book, is never explained or quantified. But if  the levels are wrong, whatever that means, you need to add the right kind of microbes to fix the problem! How can you fix the problem if it is not defined?

Most gardens have a mixture of both groups of plants growing just fine. I grow grasses, perennials and shrubs in the same garden, with their roots close together – they are all doing well. It seems that most plants grow in a balanced environment – some bacteria and some fungi – some nitrate and some ammonium.

Is this a case of taking some scientific facts and turning them into a complex gardening practice?

All Plant Nutrients are Tied Up in the Microbes

The authors seem to use the term nutrients to mean both the traditional plant nutrients – K, Mg, Ca etc, as well as all of the complex organic molecules found in living organisms. Most of the contents of microbes are not nutrients that plants can use, even if the microbe dies. The microbe consists of large molecules like DNA, proteins, and carbohydrates which first need to be broken up into smaller and smaller molecules until the free nutrients are released.

The book also ignores the plant nutrients found in soil, and the role soil plays in holding nutrients. The majority of nutrients plants use come from soil and pieces of organic matter. Both of these hold the nutrients until they are released into the water surrounding the roots.

In her lectures, Dr. Ingham makes it very clear that the mineral components of soil contain all the nutrients plants need. She goes on to say that soil contains enough nutrients to grow plants forever! In Teaming with Microbes the role of soil as the main nutrient source seems to be ignored.

The Chicken and Egg Conundrum

Much of Teaming with Microbes, as well as the soil food web theory is based on the idea that if you add the right microbes to soil, they will condition the soil environment around the roots to make it suitable for plant growth. Add more bacteria and they will make the soil alkaline. Add fungi and they make it acidic. The microbes are controlling the whole thing. Is this really true?

An alternative view is that the plant roots create an environment around themselves which in turn provides an environment for the right microbes to inhabit. The plants create their own desired environment. They even control when and if fungi connect with their roots. This is the more accepted position – plants are controlling the environment around roots. The microbes are invited guests into the environment.

Numerous recent studies show how plants change their exudates to cultivate the right kinds of microbes at their root surfaces. At the same time, the scientific evidence shows that adding microbes to soil using things like compost tea, have very little impact on growing plants in the field. This strongly suggests that microbes are not making the soil suitable for plants. Instead, plants are making the rhizosphere suitable for themselves.

Adding Bacteria to Soil

Both the soil food web and the idea of using compost tea base their theories on the concept that adding bacteria back to soil is beneficial. How many bacteria are they adding back to soil?

Teaming with Microbes provides some numbers that we can use to answer this question. They suggest that a 5 gal pail of ACCT (aerated compost tea) is sufficient for 1 acre, and that ACCT has 4e6 bacteria per teaspoon. They are adding 4e5 (400,000) bacteria to every sq ft of soil.

That sounds like a lot, but consider this. A gram (weight of a paper clip) of half decent garden soil contains 100,000 bacteria. A sq ft of soil, 6” deep, contains 2e9 bacteria. That is 2,000,000,000 bacteria. Will adding 400,000 more make much of a difference?

This idea of adding small amounts of bacteria to soil does not seem logical, and so far science has failed to show any consistent benefits in field trials. Adding microbes seems to have little effect on plants except in some special cases.

A Closer Look at Teaming with Microbes

For a more detailed look at specifics in Teaming with Microbes have a loot at these followup posts.

Teaming with Microbes – A Close Look, Part 1

Teaming with Microbes – A Close Look, Part 2

References:

  1. Teaming with Microbes – A Gardener’s Guide to the Soil Food Web, by Jeff Lowenfels and Wayne Lewis, Timber Press Inc, 2006.
  2. The Roots Of Your Profits by Dr. Elaine Ingham https://www.youtube.com/watch?v=x2H60ritjag
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Robert Pavlis
Editor of GardenMyths.com
I live in southern Ontario, Canada, zone 5 and have been gardening a long time. Besides writing and speaking about gardening, I own and operate a 6 acre private garden called Aspen Grove Gardens which now has over 3,000 perennials, grasses, shrubs and trees. Yes--I am a plantaholic!

I hope you find Garden Myths an educational site that helps you understand your garden better.

18 Responses to 'Teaming with Microbes – In-depth Book Review'

  1. Marnie Lett says:

    Hello! Often we are seemingly referring to “more” in your critique and the book in terms of amount, but I would love to hear about “more” in terms of diversity? How would I add more diversity?

    Thanks!

    • If diversity is defined as the number of species present, then you need to find more species and add them to your soil. We can probably assume that soils from other locations and of other soil types, and other vegetation has different species. Moving that should increase diversity.

      but … how do you know this worked? You can’t see or count species.

      Bringing new species to your soil is no guarantee they will prosper – they might just die. Secondly, how do you know that this increase in diversity is a good thing? You might introduce a pathogen that is not controlled by your local species. man has done that many times with larger animals and insects.

      If the microbes like to live in your soil, they will find it. Just feed the ones that are there, or the ones that find your garden.

  2. Nice post and feedback on the book. I certainly do not believe many of the statements related to their philosophy, so I rely on folks like you who do read the popular gardn culture books and critque them. I can only comment on a couple of the subheadings.

    (1) Synthetic Fertilizers and Pesticides Kill All Microbes

    This is where people have little understanding of what goes on with regards a plant’s genetic information in the presence of perhaps overwwhelming fertility. If the plant is surrounded with an abundance of fertility (synthetic or organic), it’s epigentic switches will shut of the signaling the plant provides in advertising of any nearby fungi to colonize it’s rootsystem. If fungi is already colonized on a plant’s root system, then over loading the soil with synthetics would trigger a shutdown of this messaging component and the fungi will detach. The plant has no need at this point of the fungi services. Of course the synbiotic fungi without it’s host wanting it will die. So I suppose it’s how to wish to interpret what happens. Agricultural soils will often be devoid of a lot of healthy symbiotic spores.

    Mayn long time traditional crop plants for example like certain cultivators of Corn, Wheat, Oats etc, may not be mycorrhizal any longer, even though they traditionally once were. Epigentics covers a lot of interesting environmental factors and diet being one of these. So mcuh of the modern industrial genetic manipulated crops seeds will not work without synthetics. Now whether or not the Biotechs knowingly or unknowingly [in otherwords by accident] engineered these crop to shut down their symbiotic messaging, I’m not really sure, but I know Monsanto has accused farmers in the poorer countries who failed with their seed that such failure is because they did not purchase the synthetics their seed was designed or engineered to work with. Many of the heirloom seed varieties these famers used prior to the switch over didn’t require much in the way of fertilizers, which I noticed a couple of instances references in at least two documentaries, one being “World According to Monsanto” which dealt with peasant farmers in south Mexico and the other which dealt with farmers in India. I just wish more people would refer to the role epigentics plays in all of this. The challenge though is teaching this subject in a way the common layman type people can understand.

    (2) Different Plants Need Different Amounts of Fungi in the Soil

    I found this interesting for one reason only. Last year in a California Invasive Plants forum I belong to on Facebook, I researched a common invasive annual, which is a true ruderal [bactieral soil system], but at a certain specific point in it’s life development when it begins to produce flowers and manufacturing it’s seed or fruit, it does become mycorrhizal. What it does is send out a chemical messaging to alert any spores or fungi mycelium that it wishes to cooperate in a symbiotic relationship, then are fruiting, it stops the relationship and goes back to it’s ruderal state until it dies. Again, epigenetics and turning ‘on’ or ‘off’ switches for specific informational requirements. There is so much we do not know. But this bit of news to me was kool.

    (3) Different Plants Need Different Amounts of Fungi in the Soil

    I didn’t really understand this part of the book they were commenting on all nutrients are locked up in microbes. Nutrients are often locked up in minerals and only microbes (fungi) can manufacture acids to release these and even bore holes through rock to obtain these and make them available to plants. So maybe they meant this, but just gave a bad explanation.

    (4) Adding Bacteria to Soil

    This is another i didn’t quite get. Yes, I’ll add a fungal/bacterial mix back where I come from where decomposed granite soils in hew development basically have nothing in the way of organic matter, not even topsoil. Agricultural soils would also be a good candidate for this since decades of industrial practices can leave a soil without large healthy populations of at least good mycorrhizal fungi.

    In any event, I enjoyed this Robert, thanks. I’ve neve really related to or actually heard this Ms Ingram’s talks, but I see them on YouTube. Tried once to listen, but turned the video off.

    BTW, I didn’t realize my “earthsinterface” was being used here with WordPress, but this is Kevin Franck from Google+

    • I also read about a native plant in Europe that does not usually interface with mycorrhizal fungi. But in one mountainous region it does. It is believed that in this region it needs the nutrients the fungi can provide, but in most soils it does quite well on its own.

  3. Joan smith says:

    Very interesting and fair assessment of the book lMO. I hope you do the same for Mycellium Running by Paul Stamets

  4. Brian Skeys says:

    An interesting and informative post. I have worked in agriculture all my working life and gardened since a child, the older I become the less I seem to know about it. It is stimulating to continue to learn.
    Thank you.

  5. Tony Cuthbert says:

    Hi Robert. Another good article. I am amazed that you could get through the whole book. I thought that it was going to teach me something worthwhile about soil microorganisms and their relationship to the fertility of the soil based on good evidence but I could not force myself past the first chapter. Very disappointing for someone genuinely interested. It is so obvious that we need a good biochemistry of mineralisation of organic matter – something that we don’t yet have. See if you can interest one of your scientist friends in doing the research. Meanwhile does anyone want to buy a book. Almost unused.

  6. Richard P Thomas says:

    Your last sentence in this review ” Adding microbes seems to have little effect on plants except in some special cases” is a perfect segway to my question which is, will you consider sharing a list of those special cases? I have had an arborist doing root feedings to Rhododendron and some conifers with subsequent, observable improvement to these ailing plants. These same plants have been receiving annual top dressing of compost and fertilizer but still turning chlorotic until the compost tea was applied in a root feeding. Of course there may be other things at play, perhaps you will know what else could be affecting this positive outcome? This is not a challenge to your statement, I am very interested in your keen observations and experience, and on a quest to better understand garden myths and mysteries. Appreciate your website and blogs greatly!

    • I have not looked into ‘special cases’ but have come across a few. Terrestrial orchids are very particular about which fungus they associate with in the soil. Some claim that adding the fungus helps them grow when they are transplanted. There are also some agricultural research that shows adding particular bacteria to beets can reduce certain diseases. The idea being a competition between the good guys and the bad guys.

      Rhododendron are very sensitive to alkaline conditions. Most compost is slightly alkaline. It is quite possible that a root feeding of more acidic material will help the chlorosis. Was it the microbes in the tea, or the other chemicals in the tea? We don’t know.

      One of the issues with compost tea is that there are no standards for making it. There are adopted methods, but input material is not controlled. So it is very difficult to compare different teas. There are studies that show it working. There are others that show it does not work. It is quite possible that certain brews in certain situations have benefits.

      • Richard P Thomas says:

        Thank you, the insight that other ingredients (not the microbes) in the compost tea might be affecting the Rhododendron root feeding in a helpful way seems quite probable in light of your remarks about microbes and how little is known about the lot of them.

  7. Lee Reich says:

    I am reminded of one of Dr. Ingham’s lectures I attended. It took place outdoors at a bucolic site with nicely clipped lawngrass in the towering shade of a large red oak tree. Dr. Ingham was “teaching” that trees like fungally dominated soils while grasses like bacterially dominated soils. Most of the audience sat rapt and in agreement, disregarding the juxtaposition of healthy lawn beneath them and sturdy limbs of the healthy tree above them.

    • Great visual. Maybe nature is smarter than we think.

      • Tony Cuthbert says:

        What does “like” mean anyway Lee?

        • Tony Cutbert
          “What dies “like” mean anyway Lee ?”
          ———————————————–

          Lee is not refering to trees as being sentient beings. But trees do have genetic programming which has instructions for sending out chemical messaging signals for which mycorrhizal fungi will respond by colonizing the tree’s rooting infrastructure near the feeder root hairs. The word like is simply a human term for explaining how from an observational human standpoint, when a tree colonized with a healthy nad has healthy lush foliage as a result, then it appears as if the tree “likes” mycorrhizal fungi. Any side by side containers experiment where group ‘A’ container trees have Fungi and Group ‘B’ trees do not have fungi, there is a dramatically marked contrast in growth, health and vigor in the appearance of Group ‘A’ over ‘B’

    • Actually what she was stating was scientifically incorrect. Most grasses, especially perennials are mycorrhizal. Perhaps she may have been thinking annual grasses or other ruderals which are also annuals we consider weeds. This is certainly true of farming where many grain crop plants like corn, oats wheat, etc are mycorrhizal and if they are in soil where mycorrhizae is not present, then weeds (ruderals) will outcompete the mycorrhizal plants for phosphorus. Hence the need for both synthetic herbicides and fertilizers. But grass (most lawns types that I know of] are mycorrhizal, so trees would do very well near or in lawns. But depending on the trees and the climatic ecosystem they hail from, other things like too much wetness do not favour them, but it has nothing to do with either fungi or bacteria. Too much wetness is the proble,, especially where I come from in SoCal where example trees like the native Oaks dislike it, but riparian trees like Cottonwoods and Sycamores love the association.

      please excuse any speilling mistakes, I’m always in a hurry.

  8. Glad you read the book. Seems like a redundant waste of time. Again having healthy soil and nice plants does not have to be that difficult. Claims about synthetic fertilizers destroying soils are just a irresponsible organic zealous remark. Completely turns me off when someone wants to force an opinion on you. I’ll put my masters degree in soils against these authors any day. Imagine tying to feed the masses with their ideas and opinions? We are a long lived Polish family that had been eating farm vegetables and protein for over 110 years all raised conventional means. Soil still looks good for this season.

  9. Mark Zajac says:

    It looks like a very fair assessment of the book so thank you for a well written review. You mentioned in one of your paragraphs that, ‘unfortunately, some of the chemical descriptions are misleading or incorrect.’ Can you please explain what descriptions she got incorrect or misleading?

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