Soil

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.

Nature's Ploughs

Linocut Print of Earthworms by Manu

Linocut Print of Earthworms by Manu

This is what Charles Darwin called them: nature's ploughs. Earthworms and composting worms are my all time superheroes. My research on these gorgeous wiggly beings has been quite extensive in the last month, and I have learned so much.

Worms have hearts. Up to five sets of them. Their blood contains hemoglobin like ours. Their skin is very sensitive to light, which is why they like to live under sun shades made of decaying leaves and organic matter. Their 'teeth' are sand and rock particles inside their super powerful, muscly gizzards, which grind up organic matter.

What do they eat? Bacteria, fungi, nematodes, protozoa and organic matter: where there are earthworms, there are all of the above. Everything you need in a thriving soil food web. This alone makes it worth jumping up and down when you see them in your soil, but wait, there's more.

Soil passed through an earthworm has double the amount of organic matter it had before it went in. An acre of good soil contains two to three million of them, which can move about 18 tons of soil per year, over and over again. Doubling, tripling, quadrupling the amount of rich organic matter in your soil.

Worms also have special enzymes inside their gizzards which unlock chemical bonds chaining up nutrients. In other words, once these nutrients have traveled through a worm, they are finally in a form that plants have access to and eat. 

There are something like 7000 species of earthworms. Composting worms, such as the red Wriggler Eisenia fetida, prefer to live near the surface of soil, under leaf litter or mulch (or in your worm farm) in cool, moist, dark, oxygen-rich environments with a good amount of accessible food.

Deep-burrowing earthworms like Lumbricus terrestris are the ones that create horizontal or vertical tunnels going deeper underground, leaving space for oxygen, water and plant roots to easily penetrate the soil.

Their sensitive skin means they move out when synthetic fertilisers and glyphosate herbicides are used, subsequently leaving a gaping hole in the soil food web. No more worms, no more good microbes, a bit like the Brown Barbaloots moving out in Dr Seuss' The Lorax.

We need to look after these burrowing, shredding, wiggly, five-hearted beings with all our might.

Lyttleton Gardens: a Wholistic, Productive Garden Project

Just thought we'd show you some photographs of our ongoing productive garden project in Lyttleton Gardens. A few months ago, Cam and I (Manu) embarked on a mission to turn the side garden and the little orchard behind the shop into a healthy, productive vegetable patch and food forest.

The space was very overgrown and grasses had taken over much of the side vegetable garden. The entire site is on a slope and rainwater had eroded much of the soil along paths. The mini-orchard has a wonderful variety of established fruit and nut trees, and our aim is to slowly transition from an orchard to a food forest system by incorporating a diversity of forest layers: edible or medicinal ground covers, shrubs, climbers and leguminous nitrogen-fixing plants.  

We also enriched soils with compost and covered them with thick layers of woody mulches in the orchard, and grassy mulches in the vegetable garden. We're on a very small budget, and are gathering materials from local stables (lucerne, horse manure), coffee shops (coffee grinds), and kind customers (leaves and clippings).

Grapes are in the foreground and shrubby fuchsias at the back. We have planted some pumpkins here as a seasonal ground cover, goji berry and loganberry as climbers and bush beans as nitrogen-fixing legumes. Wood shavings and compost protect the paths from erosion.

Grapes are in the foreground and shrubby fuchsias at the back. We have planted some pumpkins here as a seasonal ground cover, goji berry and loganberry as climbers and bush beans as nitrogen-fixing legumes. Wood shavings and compost protect the paths from erosion.

This is the gate from the orchard into the vegetable garden, where you can get a glimpse of some lemon balm, fennel and feijoa. Again, wood shavings from a local cabinet maker protect the paths, and we're hoping to inoculate them with mushies eventually!

This is the gate from the orchard into the vegetable garden, where you can get a glimpse of some lemon balm, fennel and feijoa. Again, wood shavings from a local cabinet maker protect the paths, and we're hoping to inoculate them with mushies eventually!

We regularly aerate our compost heap, which turns all waste from the shop into beautiful, rich, wormy black goodness for the garden.

We regularly aerate our compost heap, which turns all waste from the shop into beautiful, rich, wormy black goodness for the garden.

In the vegetable garden, we've built new raised garden beds using the no-dig method, along the contour of the slope to slow water run-off and aid infiltration. Still quite young, but here we have broadbeans, dahlias, lamb's ear, yarrow, wild rocket, chinese broccoli, endive, strawberries, lucerne, mesclun lettuce, comfrey and fennel. 

In the vegetable garden, we've built new raised garden beds using the no-dig method, along the contour of the slope to slow water run-off and aid infiltration. Still quite young, but here we have broadbeans, dahlias, lamb's ear, yarrow, wild rocket, chinese broccoli, endive, strawberries, lucerne, mesclun lettuce, comfrey and fennel. 

The garden bed we wove a few months back with Gillian from Branching Out is filled with mystery flowers from our compost as well as french tarragon and chives. Stay tuned to find out what these flowers are! They are just starting to bud.

The garden bed we wove a few months back with Gillian from Branching Out is filled with mystery flowers from our compost as well as french tarragon and chives. Stay tuned to find out what these flowers are! They are just starting to bud.

Soil Building Workshop

The garden is looking gorgeous at the moment and we are getting ready for our soil building workshop coming up on Saturday November 19th. We will teach you the ins and outs of building beautiful soil from scratch by setting up no-dig garden beds in two different settings. Delicious picnic lunch hamper provided.