The Art and Science of Composting: Debunking a Few Misconceptions

Written by Manu

Above: Toby the compost tumbler in Lyttleton Gardens

Above: Toby the compost tumbler in Lyttleton Gardens

Let's face it, composting is a delicate subject. For seasoned composters, composting is a source of joy, satisfaction, but also pride, rigidity and strong belief that you've got it, you know how to compost, you hold 'the key recipe'. For people who are new to composting, it's a source of excitement as well as anxiety, as you constantly look for advice from 'experts' on how to get it 'right', not to mention the successes, failures, disappointments and a myriad other emotions. Ah the roller coaster ride of emotions that is composting!

Now that I am training in soil microbiology with Dr. Elaine Ingham and Dr Carole Anne Rollins, the two incredible powerhouses behind the Soil Foodweb Institute, I feel that I can now share info about what is actually happening biologically in a compost heap. This will help debunk a few misconceptions I have seen and heard.

I will have to break it to you though: there is no set 'perfect recipe.' Are you shattered... or relieved? People who are really good at composting seem to be the ones who know this, and go with the flow with no set recipe but a lot of knowledge on how to observe, adjust, smell, and even taste when things are right.

What goes on in your compost is heavily dependent on outside temperatures, moisture levels, ingredients, native microorganisms and a host of other external and internal factors. There are, however, a couple of things that apply pretty much universally. 

Firstly, whether you are hot composting, tumbling, cold composting or whatever else (except for bokashi), your compost needs OXYGEN to travel through it regularly. You need to aerate your compost regularly, whether it's in a pile or a bin. There are really cool, inexpensive screw-like contraptions you can use for bins these days. The good microbes you want to have in your compost and to apply to your soil are AEROBIC, which means they need oxygen to survive.

Secondly, you need a DIVERSITY of fresh, nitrogen-rich green materials (garden clippings or food scraps, composted manures, coffee grinds, bones) and dry, carbon-rich materials (like straw, dried leaves, wood chips and wood shavings). Remember to keep everything moist. Squeeze it in your hand, it should let out a maximum of one drop of water and feel moist. 

Thirdly, I find ratios a little hard to understand. I prefer Elaine Ingham's bucket method. Lets keep it simple. A good ballpark reference is at least three buckets of dry carbon-rich materials need to be added for every one bucket of nitrogen-rich materials. This applies to hot and cold composting! Many people keep adding food scraps to their bin thinking they will magically turn into compost. Although compost is indeed magical, it needs all players to be present. Otherwise the end product is rotten, putrified organic matter.

The nitrogen-rich materials are what generates bacterial activity which makes the pile heat up. If you have too many nitrogen-rich materials, your heap will heat up too fast too quickly and kill everything. Strong smells of ammonia, vinegar, vomit, poo in your bin or heap indicate that anaerobic microbes have taken over and are producing organic acids that are toxic to plants.

This is by far the most common mistake I have seen in home as well as large scale composts: too many nitrogen-rich materials, not enough carbon rich materials. Aerate it, add loads of dry, carbon rich materials to kickstart the process again in the right direction. Do not add lime as lime is (chemically speaking) a salt, and kills many beneficial organisms.

Hot or cold?

There is a little bit of confusion as to what constitutes 'hot' and 'cold' composting. In reality, all composts heat up to a degree. This heat has nothing to do with heat from the sun or outside temperatures. It is generated by microbial activity. In fact, I personally never put any of my composts in the sun as UV rays from the sun tend to kill beneficial microbes on the surface of your compost, or heat from the sun will 'cook' them in your bin.  

'Hot' composting involves buiding a big heap or bin all at once and letting it heat up in the centre. This heat (which can reach 70 degrees celsius or higher) has nothing to do with heat from the sun or outside temperatures. It is generated by microbial activity. Aerating the heap by turning it as soon as it hits the 65 degree mark, is essential because we do not want it to get too hot (no hotter than 65 degrees celsius), as this will annihilate all the microorganisms you need in your heap. I really suggest getting yourself a compost thermometer to take the guesswork out of the equation. Hot compost heaps tend to be more prone to drying out to water well when you build the heap and check the moisture each time you turn it. Remember a hot compost heap is all made at once i.e. no adding as you go. HOWEVER, if your standard compost bin is heating up, you are indeed hot composting, and it's time to aerate it. 

Cold composting involves adding as you go, which means it should not heat up anywhere near as much as a hot compost. Remember, for every one bucket of food scraps, you need to add three buckets of dry stuff. One cautionary note: anything that was cut when it was green is nitrogen-rich, even if you then let it dry. For example, dried up grass clippings are still a nitrogen rich material. Remember to check the moisture by squeezing it in your hand. Cold composting takes more time, but the end product has a wider diversity of beneficial microorganisms.

What about compost tumblers?

Technically, if you have a large enough tumbler, you can make hot compost (all at once) or cold compost (add as you go). I personally like to cold compost with my tumbler because it makes the cold composting process much faster through more frequent turning and, as I mentioned, the end product is incredibly rich and diverse in beneficial microorganisms.

I hope this helps debunk a few misconceptions and myths on composting and encourages you to delve into its magic!

Yarrow Gardens: Building a Food Forest From Scratch

Yarrow Gardens: Manu's back yard in the Lower Blue Mountains. In this shot, you can see Tuscan kale, yarrow, mugwort, rosemary, chamomile, dandelion, statice, broccoli, nigella, french sorrel, valerian, loquat tree, dwarf avocado, carrot and sweet potato.

Yarrow Gardens: Manu's back yard in the Lower Blue Mountains. In this shot, you can see Tuscan kale, yarrow, mugwort, rosemary, chamomile, dandelion, statice, broccoli, nigella, french sorrel, valerian, loquat tree, dwarf avocado, carrot and sweet potato.

In this post, I wanted to speak a little bit about my process setting up Yarrow Gardens: my home food forest in Lapstone, which sits on a standard, quarter acre block. I'm hoping this post will help those of you in suburban and peri-urban environments get started growing regeneratively in your back yards.

I live in the lower Blue Mountains, which has a warm temperate/subtropical climate, very different to Lyttleton Gardens, which sits between warm temperate and cool temperate.

When we first moved into our standard quarter-acre block, the sloped back yard was composed of three tiers of impacted, eroded, sandy, shallow soil covered in couch grass. Couch grass seemed to be the only plant resilient enough to grow in this depleted, eroded soil. A beautiful, twenty meter Eucalyptus tree stands tall in the middle of the yard, and friends and family assured me I would never be able to grow anything successfully because of it. I didn't know much about growing things at the time and my dreams of a veggie patch and fruit trees seemed close to impossible.

It was then that I embarked on my Permaculture studies, learning about ecology, microbiology, climatology, soil restoration, regenerative farming, holistic management and regenerative design. I slowly gained enough of an understanding of natural systems to be able to make conscious decisions about where to plant, what to plant, when to plant it, how to regenerate my soil and care for my little patch of topsoil.

My perspective had changed. I no longer saw plants as 'good or bad,' as I could finally understand the function of each plant within an ecological system. 'Weeds' were no longer evil, annoying plants to be pulled out, but rather resilient pioneers in charge of quickly protecting and attempting to restore bare soil after a disturbance. In a natural forest ecosystem, there is no bare soil, and that is largely thanks to their hard work.

The great big majestic gum tree was no longer a nuisance, but rather a canopy tree to be incorporated as such into my design. Being a medicinal plant lover, being able to pick medicinal plants straight from the garden to chuck into my kettle was one of my goals, along with having a good continuous supply of fresh fruits, berries and vegetables.

My partner Steve and I rented a rotary hoe and used its shallowest setting to uproot the couch grass. I got hold of about ten cubic meters of good aged mushroom compost (always check the pH as it can be way too alkaline) which I generously covered the soil with (about 15cm), followed by a good layer of locally sourced wood chip. This allowed me to begin planting and kick-started the process of restoring the soil by adding some organic matter.

Stage one

Stage one

Six months later

Six months later

Twelve months later

Twelve months later

The tree you can see in the top photograph is mugwort, a medicinal bush that I shape into a tree. It was a tiny seedling when I first put it in and grew very vigorously. I also bought some dwarfed or small trees to form an understory layer such as loquat, avocado, banana and pawpaw. For shrubs, I bought seedlings of fast growing plants like golden fruit of the Andes, wormwood, native ginger, Mediterranean herbs, perennial basil, midjim berries, acacias,  native mint, lemon verbena, comfrey, yarrow, and nettle. I broadcast seeds of nigella, roman chamomile, cornflowers, brahmi, silverbeet, echinacea, parsley, valerian, parsnip, carrot, daikon, chives, wild rocket, red sorrel, radish, warrigal greens and planted bulbs of potato onion, perennial leeks, Egyptian walking onion and garlic.

I installed drip irrigation last spring to make sure the soil was always kept moist enough for fungi, bacteria and earthworms throughout dry summers. Worm castings, seaweed solution, homemade compost and wood chips we my sole inputs for about a year. I also started inoculating my seeds with arbuscular mycorrhizal fungi (powder mixed with a little water) just before broadcasting and inoculated all my legume seeds with the appropriate bacterial inoculant (see my previous post on Nitrogen fixation).

We finally incorporated chickens into our system in the middle tier, where they are rotated to a different area every 8 months. They are fed grains and medicine from our garden as well as some bought organic feed. Their poo feeds and accelerates my compost, their eggs are a nutrient powerhouse for us. The system is thriving with minimal external inputs. We have nuts, fruits, berries, green veggies, eggs, potatoes, sweet potatoes and much, much more, providing us with a diverse, balanced diet. I occasionally foliar spray my plants with fish emulsion (fermented fish guts) and whole cows milk to keep them strong and healthy, but barely need to add anything to my food forest soil.

I feel good knowing that all of my perennial edibles and medicinals are storing carbon in the soil for the long term, while annuals growing among them are harvested regularly. Peanuts, potatoes, sweet potatoes, herbs and veggies now pop up on their own. If anything were to happen, we would have the ingredients to a balanced diet and fresh rainwater at our doorstep. An important element in hindsight was building paths throughout our food forest and maintaining them, for easy access and harvesting. I would say the process of building a balanced, productive system takes more or less 4 years, but as you can see in the pictures above, you can do a great deal in just 12 months with careful observation.

I want everybody to experience the joy of building their own little thriving ecosystem, providing refuge for wildlife, insects and microbes, whilst harvesting a bounty of produce. I hope this little blog post will provide you with some inspiration and tools to carefully observe your site and work with its specific conditions to design a healthy little food forest of your own.

August Winds

Most Blue Mountains locals are familiar with 'August winds': intense North-westerlies that sweep through the Mountains, tunneling down sides of houses and alleyways.

Lyttleton garden is currently suffering from a nasty case of August winds. Our little veggie patch has garden beds contouring a downward slope along the side of the shop. Strong winds tunnel down the hill, eroding the soil, drying it out, reducing it to powdery dust.

We luckily have a load of beautiful ready compost started by Cam a few months ago. I find myself adding a nice thick layer of it every week in August on the most affected garden beds at the top of the hill. I cover it with an aged, heavy woody mulch, as sugarcane or straw would instantly be blown away.

I began working on this garden exactly one year ago, and worriedly asked some locals if it was always this windy up here in Lawson. "Aaah, the August winds," they replied. Cam and I were eager to start growing things in this slopey garden, but also realised we needed to observe and interact with it first. Luckily the winds subsided in September.

I'm still learning this space one year on, and am plotting to take some lavender cuttings from my garden plants for us to strike tomorrow during our propagation workshop. We will be making our own propagation mix by mixing our sifted home made compost with sand, coir and worm castings from our worm farm. My lavender cuttings will be super happy in this mixture.

When ready, they will act as insect-attracting, fragrant windbreaks on the North Westerly side of Lyttleton garden. Hopefully in time for the next August winds.

Life webs

A rain-soaked spider web in Lyttleton Gardens.

A rain-soaked spider web in Lyttleton Gardens.

After you've been looking after a productive garden for some time, a wonderful thing happens: you get to the point where you are confident enough to sift through the myriad of information (and misinformation) out there, and realise that you have understood living systems enough to trust yourself.

My personal "aha" moment happened after reading a book by Jeff Lowenfels entitled Teaming With Microbes: The Organic Gardener's Guide to the Soil Food Web. I was intrigued by the term soil food web. I'd heard of food pyramids and graphs, but was drawn to the idea of a food web. It makes so much more sense. After all, all living things are inter-connected and inter-dependent. We've lost sight of that a little bit, often choosing a more symptomatic approach to many issues.

I looked into the person who initially came up with this term. It was Elaine Ingham, Doctor of Soil Microbiology at Colorado State University. The Soil Foodweb Institute, founded by her in 1996, has been helping conventional farmers 'rehabilitate' their soils, and switch to growing organically and regeneratively. She worked extensively in this field in Australia, and started the Australian branch, Soil Foodweb Institute (Australia).  The Soil Foodweb International website contains a huge amount of free information and research in the field, which I really recommend to anyone interested in the science of growing things.

Without getting to scientific about it all, it's important to remember that soil is populated by squillions of living things, which directly or indirectly depend on plants and plant roots to obtain food. In turn, plant roots depend on them to eat. Bacteria and fungi make nutrients bio-available to plants by converting them to a form plants can eat. It's a swap system!

Synthetic nutrients are plant fast food, as they are already in a bio-available form. So, what happens when we feed our plants synthetic fertilisers? Well, essential living things like bacteria and fungi move out. They are no longer needed by the plants and don't like the salts in fertilisers. In turn, there is no food for earthworms, and their predators, and their predators' predators, and so a mass exodus happens. All life in the soil disappears. The web of life is broken and plants become junkies, fast food junkies. The soil becomes "dirt" as Elaine Ingham puts it. Lifeless, erosion-prone dust.

This is why growing regeneratively is so important. You are a custodian of all the living things in your soil. Feeding your soil homemade compost, worm castings and aerated compost teas makes sure there is food for everyone in the web, with very little need for external inputs. Try not to disturb it too much, as the earthworm will aerate it for you. Pitchforks are relatively worm-friendly if used appropriately.

Let's get something straight though, the process of building living, healthy soil takes time and patience. Keep piling on that organic matter and remember you are feeding many living things, which in time will multiply. After quite some time, all that work pays off and you will have to do less and less, as the web will be complete and self-regulating. What a wonderful, joyful prospect that is for a budding grower of things.

Soil food web diagrams from the Soil Foodweb International website.

Soil food web diagrams from the Soil Foodweb International website.



Our current challenge: the Rutherglen Bug (Nysius vinitor)

Each season we encounter different challenges when producing and maintaining food crops. Weather, pests, disease and even time can become huge obstacles in achieving our goals and a good harvest. This season there is a new challenge that has been absent in some years from the agricultural scene, the Rutherglen Bug (RGB).

The RGB is a native species to Australia that breed on a wide range of native plant species and plants considered to be weeds. RGB have eight generations a year. In spring and summer RGB eggs take 3-4 weeks to become an adult. Adults live up to four weeks, in this time females will lay up to 400 eggs.

RGB migrate in large numbers as adults, typically with storms or strong winds, once inland breeding areas start to dry. According to the Queensland Government’s Department of Agriculture and Fisheries, when there are larger populations of RGB in a season, populations are dominated by migrants from inland breeding areas.

Once the bugs arrive to Eastern Australian agricultural regions, they will breed on plants similar to the inland species they migrated from (weeds). RGB are predominantly a seed-feeding species, affecting plants mostly at the grain filling stage. Though little is known about the capacity of damage caused by RGB on crops other than Sunflower. Feeding wounds will allow entry by bacteria and fungi, facilitating disease and infection. Then once the host plant dies out, RGB move to crops or other plants.

The most commonly recorded predator of the RGB is egg parasitoids. Although, like all control methods for RGB, the contribution to population control will be limited depending on the density of RGB adults. There is little data on the natural enemies of the RGB but spiders are thought to play a role.

A Collective View of Past Studies

In an experiment by the Department of Agriculture at the Biological and Chemical Research Institute, Rydalmere N.S.W, different culturing methods for the RGB were undertaken. There were three approaches to culturing the RGB: 1. Feeding on Seed Only, 2. Feeding on Vegetative Growth Only, 3. Soil Selection Experiment.

The aim of the experiment was to provide necessary information so the laboratory could maintain a culture, without introduced RGB from wild populations. From the results, the lab was able to maintain large numbers of nymphs and adults from early 1971 to mid 1973.

Something that was Interesting in the soil experiment, female RGB showed a definite preference for a particular soil, of the ‘series’ of soils tested. The females prefered the dry, sandy loam with moisture content below 30 per cent, to lay their eggs.

After enormous numbers of RGB were recorded during early 2007-08 in Central Queensland, Darling Downs, and northern NSW, research funded by Grains Research and Development Corporation (GRDC) observed the impact and best control of RGB on Sorghum. Data on the RGB impact and best management method was collected with good results.

The research found that seed set in sorghum reduced if more than 50 RGB per head, when present during flowering. The most effective control methods were found to be using alphacypermethrin and deltamethrin for controlling high densities of RGB in sorghum. GRDC are researching further fungal biopesticides, which won’t disrupt the beneficial insects.

It is thought Metarhizium anisopliae, fungi in the phylum Ascomycota, could be effective. These fungi are an entomopathogenic fungi that grow naturally in soils throughout the world. Entomopathogenic fungi act as a parasitoid and kill or seriously disables insects by causing disease.

Further research seems like a good idea as the previously mentioned poisons both contain Pyrethrin, plus some other nasties (Piperonyl butoxide, google it). Pyrethrins attack insects nervous systems, effectively disrupting the life cycle of any treated insect. This knowledge has been used for thousands of years.

Pyrethrum is a known genus of several Old World plants, now classified as either Chrysanthemum or Tanacetum. By drying and crushing Chrysanthemum cinerariifolium and Chrysanthemum coccineum flower heads, different methods of extraction can be used. Individual research and experimentation is always the best approach from here. We have found that enriching the soil with plenty of organic matter and mulch keeps humidity levels low. RGBs prefer sandy soils to 'sticky,' rich soils. Compost also helps strengthen weakened affected plants.


Attia, F & Elshafie, M 1973, ‘A TECHNIQUE FOR CULTURING RUTHERGLEN BUG, NYSIUS VINITOR BERGROTH (HEMIPTERA : LYGAEIDAE)’, Biological and Chemical Research Institute, Department of Agriculture

Australian Grain, Rutherglen Bugs Taint Harvested Grain’ [online], Vol. 17, No. 4, Nov/Dec 2007, viewed 20 December 2016, <;dn=273488473150890;res=IELHSS>

Queensland Government 2010, Department of Agriculture and Fisheries, ‘Rutherglen bug, grey cluster bug’, viewed 20 December 2016, <,-grey-cluster-bug>

Miles, M, Lloyd, R, Murray, D & Hauxwell, C 2008, ‘New research on the impact and control of Rutherglen bug in sorghum’, Australian Grain, Vol. 17, No. 5

McDonald, G, Broadley, RH, Smith, AM & Blackburn, MD 1986, ‘Evaluation of insecticides for 'Nysius vinitor' Bergroth’, General and Applied Entomology: The Journal of the Entomological Society of New South Wales, Vol. 18

Wikipedia, 3 June 2016, Metarhizium anisopliae, viewed 20 December 2016

Wikipedia, 29 October 2016, Entomopathogenic fungus, viewed 20 December 2016,