Companion Plants and How to Use Them by Helen Philbrick and Richard B. Gregg

I give this book 9 out of 10 acorns

This a real gem in my personal library. I came across this book just a few weeks ago, researching some material for personal interest in plants, roots, and concepts we care a lot in permaculture as: dynamic accumulators. As I was in the middle of reading other books I kept it on my pile of "Have to read" books, and thought getting to it later on. Just couldn't manage doing so. I had already read some work published by the authors and know how well and clearly they write.
This book was first published in the fifties and the research referred to in its pages comes from extensive work done all over the world and by many people related to biodynamic practices.
I must admit I'm not in biodynamics actively, I've read some works on it, and know something about Steiner, but never the less reading the work that is published by the biodynamic association is always very interesting. They do a hell of a job experimenting and observing.
Just think about the work Pfeiffer did on weeds and especcially with Cromatography, directly related even to companion planting.
This book has a brief introduction which I found very interesting. They explain what companion planting is and how researchers and gardeners actually got aware of the fact that the topic was really complex.
It all started while working on inorganic amendments that were thought to have a postivie effect on plants, slowly researchers were aware that there was an entire world of organic compounds that were very effective, from roots exudates, and leaf, bark or root material. All these had a direct effect on the soil fertility, its microorganisms and related together all the plants and trees growing in a patch.
Since the first publishing of this book, have we advanced in our knowledge of soil fertility, interaction and simbiosis or antibiosis between plants? Yes for sure. Is this book still valuable today? yes.
There are diverse points that make this book still very interesting.
First, as said in the introduction the perspective of this book is to stimulate research and data collection. This is not a book that you read once and put back on the shelf. This is a sort of field guide to companion planting and should be seen as a starter for personal recording of effects in companion planting.
It is actually written that the authors would like readers to share their data with them to make possible the collection of new results for a new updated edition. Has this been done? guess not, and it is a pity.
The authors clarify that the collection of data at present comes from very different experiments carried out with different methodologies, some only based on pure observation, some carried out in a protected environment like a greenhouse, etc.
Does this have effects on the value or the proof of what is published in the book? no not at all. Because as the authors say no finding, however scientific it may be, is definitive.
The authors decided it was more important to share their work even if it was preliminary in many ways, as a stimulus to work on this topic than wait for a deep research.
Second, this book still shares insight on some effects that I think have not been overtaken by new data. They are specific on some plants that really bring curiosity to try their effects out.
So how does the book develop?
it's thought of like an encyclopedia with entries in alphabetical order. There are 233 entries and of these more than 200 are on specific plants, fruit trees and trees. Let me just say Wow!
And they refer not only to effects on plants and between plants but even on animals and insects. Is everything accurate and definitive? as said no, and this really something we should think about when working with nature, can anything be definitive when we study natural ecosystems. Many say in permaculture we tend to use "It depends" as a solution for explaining many things, is this wrong? I think not, it’s an assumption of responsibility to understanding that we have been taught to fix everything in given rules, but not always can this be done, not always is this of any gain, not always is it possible to reduce natures interaction to a rule.
To sum it up I’d like to quote a phrase that is in the introduction of the book and is a quote from Goethe: "In living nature nothing happens that does not stand in a relationship to the whole". I guess that’s the only rule we can write trying to reduce nature to a concept.

Might like to get hold of a hardcopy of this sometime.   Not so long ago, I spent no small amount of time researching companion plants for a project. I found there was a wealth of folklore but little else that was concrete. Not that I have anything against folklore it is just difficult to differentiate the wheat from the chaff as it were.