Archive for January, 2015

The Permaculture of Soil, Part 2.

Written by Caroline Aitken on . Posted in Uncategorized

The Soil Food Web.1. web

In my last post I said that while organic matter constitutes the smallest proportion of the non-living components of the soil, it may have the biggest importance. This is because it’s the basis of the soil food web (the food chain of the soil ecosystem) and it has many special properties that enable life to thrive. Organic matter in the soil starts out as dead plant and animal material which either falls on to the surface or occurs beneath it (dead plant roots and soil organisms). These materials then go through various stages of decomposition thanks to a variety of soil organisms and eventually become a substance called humus. This dark brown/black goo is what gives a good soil it’s rich colour and to a large extent, its fertility.

Here are some of the ways in which organic matter affects soil:


Most gardeners know that earth worms (lug worms) are their allies. Worms live in the top soil and come to the surface to find fallen plant materials such as leaves. They pop up and search around until they find something good, then they drag it down into their burrow, where they wait for microorganisms to help break it down so they can eat it. Their digestive system uses mineral particles from the soil to help to grind up the plant materials which means that what emerges from the other end of the worm is a gooey combination of decomposed organic matter and minerals – perfect soil! Simply by pulling organic matter from the surface in to the soil the worms are playing a vital role in incorporating it into the food chain. Other helpful behaviour is the burrowing that worms do, making thin channels through the soil which improves the structure and allows air and water to penetrate. The gooey nature of worm castings and humus helps to form aggregates by sticking particles together into ‘crumbs’. This makes the soil stable and less prone to erosion or compaction.

14. worm pulling leaf

An earth worm pulling a dead leaf down into it’s burrow

Improved structure means that the soil can hold on to water for the plants, but also be well drained and not prone to water-logging. Dead plant materials can be fibrous and hold water and air, while humus acts like a sponge, absorbing water and with it, nutrients.

Plant Nutrients:

Organic matter contains a certain amount of nutrients which plants need, but this varies according to what it’s made of. Often these nutrients are locked up in a non-soluble form that is unavailable to the plants, and are only made available via microbial activity which converts them to a soluble and available form. Once nutrients are soluble they are also leachable and will be washed away from the plant’s roots unless the soil can hold on to them. This is where the water-holding ability of organic matter is so important. The water held contains soluble nutrients – plant food. Humus has between 2 and 10 times the nutrient holding capacity of clay, therefore small amounts make a big difference.

Woody materials and tree leaves are generally consumed by fungi which form large networks of mycelium beneath the surface of the soil. Mycelium is the body of the fungi and the mushroom is the fruit. Soil-based fungi can spread over large subterranean areas and behave in a curious and wonderful way by connecting up the root systems of different plants. It turns out these mycelium networks function as an exchange between the fungi and the plants, and between different plants which are connected. Nutrients and water can be exchanged where there is an excess in one area and a need in another. This is how plants which can ‘fix’ nitrogen (via a symbiotic relationship with certain bacteria) can make it available to surrounding plants.

6. root tip & hyphae

Fungi attaching itself to the root tip of a plant


Adding organic matter to your soil is a great way to increase the fertility because it contains nutrients, it holds air, water and soluble nutrients and it gives good structure. The affect of organic matter in soil is disproportionate to its quantity.

Soil Life:

Organic matter provides food and habitat for the organisms that make up the soil food web. These organisms help to turn organic matter in to humus, the many qualities of which are outlined above. They also make the nutrients in that organic matter available to plants and other soil life. They are the invisible factory that recycles nutrients and enables natural self-sustaining systems. As the diagram shows animals, plants and fungi are interdependent, forming complex food chains, and many co-operative and symbiotic relationships. We take organic matter out of the system in the form of food, so to keep the system functioning we must replace that organic matter in a form that will feed the system- compost, manures, etc. Other than that we need to leave it alone to do what it does, and has evolved to do over millennia.

In my next post The Permaculture of Soil, Part 3: How do we care for our soil? I will give some practical guidance on looking after what you’ve got at home.

The Permaculture of Soil, Part 1.

Written by Caroline Aitken on . Posted in Uncategorized

What is it and why does it matter?

A couple of months ago I was teaching the students on Shift Bristol’s Practical Permaculture course about how to preserve garden produce. Apart from the usual jams, chutneys and syrups I also taught some basic traditional fermentation methods. Fermentation at home is not just about wine and beer but also about food. Sauer kraut, kimchi, kefir and kombuca are becoming more popular in Britain due to their interesting flavours and apparent health benefits. It was while explaining those benefits that I referred to our digestive system as:

“an ecosystem containing hundreds of different microorganisms which help us to digest nutrients from our food – just as the microorganisms in the soil ecosystem make nutrients available to plants.”

This comment triggered a wave of invisible light-bulbs above the students’ heads as they made the connection between soil and our digestive systems, the connection being microorganisms. Last time I was teaching the ‘soil food web’ on our Design Course I explained that the roots of plants are covered in a coating of bacteria which feed off the roots and are the basis of the soil food chain. I went on to say that the leaves are also coated with bacteria which form a healthy protective barrier against disease. A hand went up and one of the students rightly pointed out that “pretty much everything is coated with bacteria”. It’s true; these bacteria are an important part of our world, and we need to understand that.

teaming 34,99We are beginning to understand the complexity and importance of our intestinal flora, but still many people are unaware of the complexity of soil life. In recent years scientists such as Dr Elaine Ingham have made great leaps in our understanding of the soil, but you could say we have only scratched the surface. There are some fantastic books available to the layperson who wants to dive in to the subject, and if you’re interested I would highly recommend Teaming With Microbes by Wayne Lewis and Jeff Lowenfells and The Soul of Soil by Joe Smillie and Grace Gershuny, but we don’t need to know all of the science in order to know how to care for the soil. We just need to understand that we must care for it and that in doing so we’re caring for our own future.

There is a still a common misunderstanding about the importance of organic food production. It is not for nothing that the UK governing body is called ‘The SOIL Association’ and yet many consumers are unaware of the reasons for this. I have overheard many a conversation about whether organic food “really does tastes better”, and whether farming chemicals “really do cause cancer” and such like. My primary reason for growing food ‘organically’ (without chemicals and working with nature) is because I want to protect the environment so that I can provide for my family now and we can all do so in the future. You could say that soil is our most precious resource – certainly Mr Whitefield said so in his Earth Care Manual:

“It is the mother of all plants, and through them the animals, ourselves and civilisation.”

So what is this incredible substance upon which we are so dependent?Soil pie chartIt may come as a surprise to see that less than half of soil is made up of mineral – that is particles of the bed rock upon which it is formed. It may also come as a surprise to see that only a maximum of 10% is made up of organic matter. On a conventional arable farm that could be as low as 1%, so all of these proportions are variable, but the chart represents an average fertile soil. In Patrick’s words a fertile soil is one which has the ability to support healthy and abundant growth of plants, and to achieve this it needs all of the above components.

Mineral particles and organic matter form into ‘crumbs’ in the top soil and the size and nature of these in different soils is known as the crumb structure. It is the space between these crumbs, known as pore space through which air and water can penetrate and be available to plant roots. A plant ‘breathes’ from every part of its body and therefore needs access to air around its roots. It also needs a constant supply of water both as a nutrient and as an essential part of its body: plant bodies can be 90% water and it enables their vascular system to function.

The proportion of air and water contained in the pore space will vary according to the weather – after rainfall it will be largely water, after drought it will be mostly air. Plants can cope with these temporary fluctuations to varying degrees, so long as they are temporary. When soil compaction occurs (compression of the topsoil due to footfall, cattle grazing or machinery) the crumb structure is destroyed and all of the air space pushed out. Waterlogging leaves no space for air in the soil, depriving the roots of carbon dioxide. So that 50% portion of space is vital for plant survival, and that is why you’ll hear growers talking about ‘improving structure’. This can mean relieving compaction, improving drainage or increasing the depth of the top soil. Most plant roots will only grow where they have access to both air and water. The deeper the roots grow, the more potential there is for abundant growth.

Soil Compaction TheOrangeGardener.Org

Non-compacted soil (left) and compacted soil (right)

Structure can sometimes be confused with texture, another term used to describe different soil types. While the structure is about how particles are joined together, the texture is about the particles themselves. This is very simple in theory. There are three types of particle – sand, silt and clay. A soil which is dominated by one of these particles is known as that type of soil, for example if it’s predominantly made of sand it’s known as a sandy soil. However, soil is generally a combination of all three in varying proportions (unless you’re on the beach or in a clay quarry!). A fairly even mix is known as a loam, and a mix with a bit more of one type is called a ‘sandy loam’ for example. Different particle types have different characteristics, so it can be helpful to know what type of soil you have so you can care for it appropriately and grow what is suited to it.

Compost heapI haven’t mentioned nutrients yet, and you may be wondering why it wasn’t the first thing on the list. The idea that mineral nutrients such as nitrogen, phosphorus and potassium (N, P & K) are the single most important factor in plant growth has, as Patrick put it “the full force of the advertising industry behind it!” Companies who sell chemical fertilisers would have us believe that’s the case, and by bypassing several millennia of evolution by throwing fossil fuels at it they have succeeded in growing food that way. But in a natural fertile soil there are many parts of the jigsaw, and the thread that connects them is the soil life – those micro-organisms mentioned at the start. In my next post I’ll explain more about soil life and how it works. How chemical fertilisers work is by liberally dowsing the soil with synthesised nutrients (made using fossil fuels), a small percentage of which will make contact with plant roots and be absorbed while the rest is leached away by the rain, ending up in the water system where it becomes a pollutant. Apart from all of the many complaints we might have about this, it’s a highly inefficient way to produce food, requiring huge amounts of energy and water while also causing pollution, loss of biodiversity and food of a questionable quality.

Organic matter is the final piece of the pie, and although it’s the smallest it is possibly the most important. Patrick muses that it is the closest thing you can get to a panacea! The many reasons for this will be explained in my next post –The Permaculture of Soil. Part 2: The Soil Food Web.

Do we have the wisdom to survive?

Written by Caroline Aitken on . Posted in Uncategorized

Last night I attended a film showing of a recent Old Dog Documentaries film called ‘The Wisdom to Survive’. The showing was organised by a local group called DANCE (Dharma Action Network for Climate Engagement) who arrange awareness-raising events about environmental issues and how we deal with them both personally and as a community.


The film is a 50 minute documentary with the tag line ‘Climate change, capitalism and community’ which explores the current situation, and the thoughts of various people whose work relates to it. Amongst those featured are Joanna Macy, Roger Payne, Richard Heinberg, and Ben Falk who between them offer the usual sobering truths and calls to action. What interested me most about the film and makes it different from others on the subject, was how it looked at the different ways that individual people respond to and cope with the situation. Throughout the film speakers offer their personal views on what needs to be done, and we see and hear from several community groups and movements who are taking action in their different ways – from guerrilla food growing on urban wasteland, to seed-saving in the developing world. Fostering community and connecting over a common cause can be the most powerful way of affecting social change, but when we are facing such daunting odds how do we deal with it as individuals?


Comminity allotments like this one in Bristol offer a chance for people in urban areas to connect with each other and nature while providing for their own food needs.

It was facinating to hear that Richard Heinburg, author of Peak Everything and The Party’s Over plays the violin to help “keep my sanity” while writing terrifying books about the real state of planet earth. Listening to other contributors it seems that art can play a very strong role in enabling people to feel connected to the planet and themselves. Joanna Macy , author of Active Hope leads the deep ecology movement ‘The Work That Reconnects‘ which in the last 30 years has helped individuals to realise their shared connectedness with the life-force that permeates everything. If more of us can realise this connection, surely it will help motivate humankind to cease the current wonton destruction of our planet and ourselves. But reconnecting is not solely about averting disaster, when we begin that journey of discovery we realise that connectedness is what makes us feel alive, happy and well. Therefore questions of whether we’ll ‘make it’ as a species or as a planet become obtuse – why do we want to survive? This film, like many others in the genre shows a stunning stream of images of mother nature at her most breath-taking, colourful and awe-inspiring. The film begins with footage of a mother sperm whale and her calf gliding through the aquamarine landscape of the ocean like they are living in a slow-motion dream world. These images created a tangible sense of wonder and joy in the room, which then turned to intense sadness as we saw the whale-hunting boats close in and fire their harpoons – shattering the perfect picture.

Oak TreeMany of the people in the DANCE group are friends of mine because we have all had some connection with a meditation retreat centre near Newton Abbot. Gaia House holds retreats where teachers offer a blend of buddhist philosophy and western psychology. I, like many others have found this approach incredibly helpful when facing the reality of climate change, species exstinction and the consequential human suffering. After watching the film we had a sharing circle where any of the 50 or so people who attended could share their response to the film. Although at first I was reluctant to stay and hear people’s emotional out-pourings, I am very glad that I did. These are incredibly difficult subjects and over the past 20 years since I began to engage with my own response to them, I have shared in many other people’s as well. I decided some time ago that rather than spending all of my energy fighting the Goliath of the capitalism and feeling hopeless, desperate and grief-stricken, I would simply endeavour to do the right thing myself, and hope to encourage others to do the same. There were a variety of responses last night, some sad, some angry, some optimistic, some full of love and appreciation, but the shared quality they all had was a vivid consciousness. By looking at the situation with eyes and heart wide open and sharing that with others we do feel the pain, but are not crippled by it. We don’t need to turn away, feeling that there’s no hope and no point. The pain we’re feeling only shows us the depth of love we feel for this planet, and it is that love we need to tap in to to keep us going.

We live in a very goal-orientated society which encourages us to believe that if there’s no hope of success there is no point in taking part. I do have hope but not in a fixed outcome. My hope is that we can all find a connection to ourselves, nature and one another which enables us to live in the way we know to be right. Not to live by rules and punish ourselves for faltering, but just to always do our best according what we feel is true. I was drawn to permaculture because it’s about positive solutions. It is about individuals and community taking responsibility for themselves and each other – a ground-up movement that bypasses the Goliath altogether. It is about preparation and resilience, but it’s not about building a bunker in the back garden. It’s sensible, rational and practical, but there is a heart to it. Anyone who is drawn to permaculture is drawn by the wish to do the right thing and improve their world.

permaculture festivals

Festivals like The Green Gathering (pictured) and Sunrise Off Grid are great ways to connect with like-minded people and positive projects.


I am reminded of one of Joanna Macy’s gems of wisdom at the end of the film

Don’t put all of your energy into defeating something which is already defeating itself.’

It’s exhausting. Instead put your energy into creating something good to replace it. If we all do that, there will be nothing to replace.

Permaculture Design Course on Dartmoor