One of the most rewarding tasks you can do when you start an allotment garden is create an area for making compost.
Whether you are a digger or like me moving to a no-dig approach, compost is everything.
The idea of making compost is often considered technical and hard work. The gardening industry supplies the solution in the array of compost contraptions available on the market. The secret to making compost, however, is understanding some basic principles and having a little patience.
Nature is a brilliant source of free information.
Take a walk in any woodland and look at the floor. Across the surface, you will see a layer of fallen leaves and twigs. If you dig below a little, you will notice a dark, rich and crumbly material. Recognise this?
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The woodland floor demonstrates the simple way composting takes place. There are no special apparatuses, no sorting of materials and no turning of the heap – yet compost is still produced.
The natural process of composting is gradual. Managed compost heaps can speed up the process and ‘managed’ doesn’t necessarily mean a great deal of work. You must accept however, it’s not like making instant coffee.
It’s important to understand that compost, when in its final, usable form, where much of the material no longer resembles its original state, still holds the nutrients contained in the original matter. It’s a huge pile of slow release fertiliser and you can get it for free.
“As long as you’re taking waste to the compost heap and then putting compost on – the nutrients aren’t going anywhere”
Ken Thompson (Interview, Telegraph).
The science of composting
Science? Don’t run away!
It’s not complicated and understanding the concepts will be hugely beneficial to you.
The Cornell Waste Management Institute (CWMI) was established in 1987. It is a program in the Soil and Crop Sciences Section, School of Integrative Plant Science in the College of Agriculture and Life Sciences at Cornell University.
Their website is one of the best, free resources on composting available.
CWMI looks to address the environmental and social issues associated with waste management by focusing on the economic, environmental and political issues. It works to develop technical solutions to waste management problems and address broader issues of waste generation and composition, waste reduction, risk management, environmental equity and public decision-making.
Cornell Unversity doesn’t just provide the theory. It recycles half of its waste into high-quality compost which is used around its facility.
(Cornel University, YouTube)
The University published a very readable research paper on the science of composting. I highly recommend you take a look.
How does composting happen?
If you were to gather up your kitchen scraps, lump them in a box and leave them for a few weeks what do you think would happen?
The likely scenario is on opening the box you would face a pile of smelly gloop. Much to the satisfaction of any local flies.
Why then does a compost pile, provided with the suitable conditions make the difference to the end product?
A compost pile is a living, breathing mound of activity. The organic matter placed on the heap is slowly broken down by teeny-tiny living things known as microbes. These single cell organisms are so small they might just as well be invisible.
Many composting systems look to create the conditions for thermophilic composting, a process that creates heat to promote rapid decomposition. It also kills off weed seeds and any organisms that cause disease.
The heat in this process is a by-product of the high levels of activity by the microbes – no fires required. You simply need to create and maintain the right conditions for them to flourish.
The process of thermophilic composting is structured much like a three-act play.
Mesophilic phase: Introduce the characters, their relationship and the world in which they live. Then they start to live their lives out. The temperature of the compost heap is low and is dominated by organisms which thrive in the moderate warmth. These microbes begin the composting process off by rapidly breaking down the readily degradable and soluble compounds on the compost heap. Through this activity, the microbes generate heat and the temperature of the compost heap rapidly rises.
Thermophilic phase: Here is where the action really kicks in. Once the temperature of the heap has risen over 40 degrees C, the mesophilic organisms give way to the heat-loving thermophilic microbes. The temperature races and these little creatures breakdown the major structural molecules in the plants.
Mesophilic phase: The climax and the resolution in the composting journey. As the compounds the thermophilic organisms thrive on become exhausted, the temperature in the heap gradually decreases. The mesophilic microbes once again take over for the final phase of ‘curing’ the compost.
In thermophilic composting, the microbes make compost. Our job is to ensure the conditions on our compost heaps meet the requirements of these microbes to enable them to do what they do. Keep them happy and they will provide us with the beautiful dark matter to feed our crops.
These creatures need the right chemical and physical requirements to enable them to grow and break down the organic matter efficiently.
In his delightfully presented book Compost: the natural way to make food for your garden, Ken Thompson does an excellent job in providing the complete picture of the process of creating good compost.
Thompson declares in his forward to the book that making compost doesn’t have to be hard work. Although he doesn’t prescribe an exact method and is honest in explaining that things will go wrong, he reassures us that if you read the guide, understand and use the fundamental principles contained within, you will become successful in producing this essential component of the kitchen garden.
The right mix of ingredients
Think of the diet of the compost making microbes as much the same as ours – a balance of energy providing carbohydrates and building material in the form of protein. In the case of compost creation, this is about creating the right configuration of carbon and nitrogen on the heap – the carbon:nitrogen, or C:N ratio.
The compost heap needs more carbon than it does nitrogen. Thompson advocates this composition is met with a ratio of three parts soft, green waste to one part woody stuff.
Types of ingredients
Thompson breaks the ingredients of the compost pile into three categories.
- Soft, nitrogen-rich – including, kitchen waste, lawn clippings and soft, green garden waste.
- Fibrous green stems like brassicas, eggshells, soiled bedding from hamsters, tea bags and soft pruning’s.
- Cardboard, hay, leaves, hedge clippings and woody pruning’s.
Let it breathe
Composting is an aerobic process. Air is vital and the compost heap is more likely to run out of air before it runs out of food. This is not what we want to happen as decomposition becomes anaerobic which is a slower process and also results in the compost heap starting to stink.
The solution? Well, turning the heap will certainly increase the level of air – but remember, Thompson promised making compost does not need to be hard work – so turning a decent size compost pile is a task we don’t want to undertake too often.
Instead, focus your attention on the structure of the compost heap. Thompson outlines in his book the dilemma this can cause – it involves the management of woody waste and the problem with it slow decomposition. The answer he proposes is in paper and cardboard which provides structure without taking a long time to break down.
The microbes and important soil beings like worms need water. The compost heap needs to maintain a level of moisture for these creatures to flourish. However, too much water causes problems with air and so again we have a balance to maintain.
“If you take a handful from the centre of your pile and you can squeeze just a few drops of moisture out of it, that’s perfect.”
– Ken Thompson
A realist approach
One of the most practical and useful chapters in Thompson’s book is dedicated to real-world compost heap management.
As I say in my about page, I genuinely believe it possible and hugely beneficial to manage an allotment despite the daily working life. If I want to demonstrate that and hopefully inspire others to do the same, I have to ensure the approach I take on the allotment lives up to that statement.
This means composting too.
Thompson rightly points out that the traditional advice to composting, with all its time-consuming rigid structures and requirements is simply not helpful to the everyday allotment gardener. By all means, if you feel strongly about it, take the traditional way – however, there is a simpler and less resource intensive approach which will bring the results needed.
“The good news is that after a year, whether turned or not, all heaps produce perfectly good compost.”
– Ken Thompson
High fibre compost heap
Thompson suggests a more appropriate approach to composting for the majority of gardeners and outlines a method developed by the Centre for Alternative Technology (Based here in Wales).
Much of the waste produced by the everyday allotment gardener will be in the form of soft waste. The only rule to managing this type of compost heap is ensuring you keep a balance between green waste and paper and soft cardboard.
This is where our old friend the worm comes into its own. In essence, this compost heap is a form of wormery. These wriggly little beauties do all the hard work – no turning necessary. Fill the bin up and leave it to turn into beautiful black gardening gold.
Wood chips have a bad rep when it comes to their use on the plot. There is an issue with turning them directly into the soil as they steal a lot of nitrogen to enable them to decompose. When I took on my plot, I was a told how the old site secretary hated them and tried to banish them from anywhere on the allotment site.
Wood chips are a great resource for creating paths. They decompose slowly, supress the weeds and add useful structure to your plot. Many people also successfully use them as a mulch on their beds. This is absolutely fine as in this state they won’t rob the plants of nitrogen and help supress the weeds. They contain a great amount of nutrients which are slowly released to your crops over a long period of time.
However, they most certainly can be composted. Yes, they take longer to breakdown than other forms of organic matter but they can turn into some beautiful stuff and can then be applied to your plot as you would any compost. Don’t take my word for it, check out Alys Fowlers article on her experience and guide to composting wood chips.
We have large amounts of wood chips delivered free to our allotments. I use a lot of them to create the paths on my plot but it would be a missed opportunity to not turn some into compost. I will be trying this out over the next 12 months.
I’ve touched on some of the topics within Ken Thompson’s really great book. If you are keen to learn more about making compost on your plot, I definitely recommend it as a practical resource.
Ken Thompson’s book is available from Amazon here: Compost: The natural way to make food for your garden