Teaming with Microbes – In-depth Book Review

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Robert Pavlis

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.

Growing Great Tomaotes, by Robert Pavlis

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.

Microbe Science for Gardeners Book, by Robert Pavlis

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


  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
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Robert Pavlis

I have been gardening my whole life and have a science background. 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!

28 thoughts on “Teaming with Microbes – In-depth Book Review”

  1. Thanks, I first posted, then read up, it took me 5 minutes to see that I had gotten it wrong… but could not edit my post
    Thanks again, and for taking your time to answer,
    yours, Anne

    do you happen to have a recommendation for literature on soil microbes which is not too scientific in nterminology?

    • There are several chapters on soil microbes in my book “Soil Science for Gardeners””

      • My goodness, I would suggest this is an impossible read for the average gardener and yes I include myself in that group. I am sure these folks have dummied the information down for me, but if they actually wish to communicate information to me they have a long way to go.
        After a short read I feel like a kid listening to Charlie Brown’s teacher.
        Very quickly technical terms with very short explanations of what these terms mean become so overlapped and overwhelming I find it simply too much.
        This book is literally teaming with scientific verbiage which negates my desire to read further. As a gardener I appreciate that I should understand more why I am adding compost or manure or sand to my plants, but this book is simply not written for me.
        I would not say it is a total waste of time, but after 50 pages I do not anticipate it becoming any more comprehensible.
        I think within these pages is very likely some very useful information, but it is presented in such a manner as to not be offered to me easily.
        I remember my first year psychology textbook was so well presented even difficult topics were relatively easy to grasp. This book is the opposite of that textbook.
        I will keep hammering away at this, it is my nature, but I find it daunting and frustrating.
        I hope others have an easier time.

        Greg Pendragon

  2. thanks for your in depth comment

    they were super helpful to me

    I teach basics of soil science (or just soil for plants) to future arborists, and I always got stuck at the compost-tea chapter,

    funny thing around here airated compost tea is a big thing with arborists, they sell it by the barrel to garden owners, swearing by it, but I am just not convinced… pretty costly too,

    one student told me about a farmer in his village who pipes fresh compost tea into the irrigation system for his strawberry fields…


    so I will go to the source and read up on stuff by Dr. Ingham

    • The problem is that most of what Dr. Ingham says about compost tea is wrong. I’d suggest you look at the real science.

  3. Robert – Thank you for all the good, scientific and useful information on your site. I have just finished reading your entry and the replies about synthetic fertilizers.
    You made a comment in the Reply forum that “synthetic fertilizer is not petroleum based”. (April 20, 2020)
    I don’t know about other fertilizers (though a short bit of research would undoubtedly provide quick answers), but Urea, probably the most common form of inorganic fertilizer in the world, I would think, is industrially manufactured (a great deal of which in the United States is made by the infamous Koch Brothers) from liquid ammonia and liquid carbon dioxide. Ammonia, in turn, is produced by the Haber Process, which involves the passage of atmospheric nitrogen and hydrogen, sequentially, over beds of various metallic catalysts.
    The hydrogen, which can be produced in several fairly benign ways, including electrolysis and biomass conversion, is mainly obtained by industrial ammonia manufacturers by “steam reforming”, using methane obtained from Natural Gas, or other petroleum hydrocarbons (or coal byproducts) as the primary raw material.
    While I would not be prepared to argue for the many “feel good” contentions about the damage caused to soil and microorganisms by urea fertilizer, I believe that you are on rather shaky grounds in contending that inorganic fertilizers are “…NOT (your emphasis) petroleum based.”. That statement, at least in the case of agricultural urea, is incorrect.
    Another important aspect of the large-scale, world-wide use of urea (and, undoubtedly other inorganic fertilizers, as well) are the various environmental threats and problems to which it contributes significantly, both with the material itself (e.g. nitrogen runoff into riparian systems) and the manufacturing processes themselves, as well as the effects of obtaining some of the raw materials essential to the production of these fertilizers (oil drilling and oil processing, large energy requirements, creation of undesirable waste products, global warming, etc., etc.).
    While solid scientific evidence may exist that synthetic fertilizers are treated and reacted to by plants in the same manner as the addition of “natural” nutrients, and while there isn’t any doubt the the (mechanical?) horse is long out of the proverbial barn, I think that, on the whole, the scientific community should be involved in finding more sustainable materials to feed the world (I’m sure many are, including the one’s involved in much “flaky” research, which you frequently debunk).
    For statistics and other facts concerning ammonia production see the “Economic and Environmental Aspects” section of the Wikipedia entry on the “Haber Process” (not a scientific journal!, certainly, but a reasonable educational summary of the subject). Ammonia production (mostly for fertilizer) apparently uses 3-5% of world natural gas production. That sounds like a “petroleum base” product to me. What say you? Thanks for your goid work. Keep it up!

    Pat Dyas
    Marysville, CA


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