Soil & Health
Making Artisanal Living Soils
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The history of composting goes back to at least 10,000BC as early farmers likely planted directly in their compost heaps. The earliest written reference to compost appears to be from around 2,300 BC. The fertile “dark earth” or “Terra Preta” of ancient Amazonia also appears to have also utilised the benefits of carbon (biochar). Today, we are re-discovering these lessons for ourselves.
Compost is a nutrient-rich organic soil amendment that brings life back into depleted soils. Known as “black gold” for its dark color, it is becoming more loved and understood as we start to rediscover and increasingly embrace sustainable practices once more.
Composting is probably the single greatest act of kindness you can do for our planet. It is a way to significantly speed up the natural process of making living soils. As humans are the only species that can do this, it could very well be part of our core function as Stewards of the Earth.
As an artisanal composter one quickly creates the perfect environment for life to thrive by mixing together (hence the Latin “composition”) and recycling organic matter, leveraging the beneficial processes of Nature’s chemistry. The process heat generated from concentrating carbon and nitrogen layers together, helps drive the composting process forward even quicker.
Types of Composting
With aerobic composting, we are trying to enlist the aid of beneficial bacteria to break down carbon and nitrogen in the presence of oxygen, to quickly render beautifully rich and life-giving humus. By ensuring enough oxygen flow in the pile, and the right ratio of C:N, we can speed up the decay process through “hot composting”. This is doubly beneficial as the heat also destroys disease-causing pathogens and weed seeds etc. It also breaks down the material far better to produce a very fine compost.
Hot composted material looks like fine black grains, where none of the original materials are distinguishable. It is a relatively fast aerobic process (circa 1-3 months versus 6 months for cold anaerobic composting), meaning that less carbon and nitrogen emissions are given off i.e., more environmentally friendly.
Materials that are high in carbon are typically dry, “brown” materials, such as wood chip, cardboard (without ink), dried leaves, straw, or any other woody or fibrous materials that rot down quite slowly. Materials that are high in nitrogen are typically moist, “green” materials, such as lawn/grass clippings, fruit and vegetable scraps, animal manures and other green manures that rot quite fast.
Vemicomposting is the label applied where one makes active use of red wiggler worms, encouraging them to move through a pile. This is especially useful if you have a lot of food waste, coffee grinds etc., as the worms will seek out, eat, and digest the scraps, producing a rich leachate in the process. However, there is no need to buy in worms, as proper aerobic composting will of course soon attract plenty of red wigglers on its own. In fact, this is a sign of a healthy pile.
Clearing Alien Vegetation
Our Amathole Mountains are a vital water catchment area for the Eastern Province. Unfortunately black wattle and other alien species have completely invaded crucial waterways, leading to lower runoff into dams. Working with Conservation International, we are dedicated to responsibly clearing this alien vegetation, and restoring native grasslands. Thankfully, Black Wattle also makes great biochar.
All About Manure
Manure is nature’s way of recycling the animal kingdom’s waste. It evolved as part of an integrated symbiotic network with the plant kingdom, just as the fungal and plant kingdoms themselves evolved to work together. George Washington loved manure for composting and commissioned the first “Annals of Agriculture” 1.
However, not all manures are created equal. “Hot” manures should never be placed directly onto your soils, as they can burn your plants. They ideally need to be composted first to gain their full benefit. Hot manures include human, horse, cow, chicken, dog etc. 2
“Cold” manures can go straight onto your garden if you want. However, they also benefit from composting and can sometimes give better NPK ratios than hot manures. Whilst hot manures are randomly shaped, cold manures are generally pelletised and include goat, sheep, and rabbit. Below is a handy NPK ratio reference table.
1. “Anyone versed in the valuable writings of the ancients upon husbandry subjects, will soon perceive the very great stress that is laid by them upon an unremitting attention to every possible method of procuring manures.”
2. Although it’s possible we don’t use human or dog manure in our compost, as it really needs to be super-heated to ensure complete breakdown of any pathogens. Male urine on the other hand is an excellent inoculant. While these manures may give a great phosphorous kick, we prefer to use bone meal in our compost.
Getting the Balance Right
Ensuring your compost has an optimal balance of life, NPK and other essential macro- and micro-nutrients is an art. Whilst the brown and green layers will give you a decent compost for most purposes, if you really want to ensure a premium product, then like most things in life you need to become an artisanal crafter.
This is where selection of your composting material becomes vital. For instance, eggshells, hair, and feathers can contribute phosphorous. Fish meal can improve your potassium content, but too much introduces too much oil that can stall the process.
Bone meal is an excellent source of phosphorous and we add a decent amount of it, even though properly sterilised bone meal is quite expensive. Bird or bat guano is a great source of nitrogen for early obvious growth, but does little for later flowering and fruiting, where potassium and phosphorous are more important. Guano is also inherently unsustainable as a source material.
What Can Be Composted?
Almost anything that once lived can be composted. We have developed our own preferences based on our local sourcing area, and you should look to do the same for your area. Even urine (notably male urine) can be added, being a wonderful nutrient source with a perfect 1:1 carbon to nitrogen ratio.
Some things that should NOT generally be composted include:
Pine or Eucalyptus wood… many commercial composters use pine or eucalyptus woodchip or sawdust. This is problematic as pine contains microscopic oils which coat beneficial bacteria and render them inactive, like a seabird caught in an oil slick. Eucalyptus yields allelopathic chemicals which are toxic to other plant life.
Diseased plants or noxious weeds… for obvious reasons.
Manure from non-vegetarian animals… contains pathogens which could cause diseases.
Meat scraps, dairy, and fats… these will rot, smell unpleasant, and attract rodents.
All types of oils, including cooking oil… for even more obvious reasons as not using pine.
All types of chemicals, including printed and thermal papers… these often contain toxic and chlorine-based chemicals which are not good in Nature.
Household dust and personal hygiene products… nowadays these contain too many synthetic fibres which don’t break down and/or are unhygienic.
Phases of Composting
Under optimal conditions, compost will proceed through three phases:
1) Mesophilic (moderate heat) phase, which lasts for a couple of days. It attracts the primary consumers that shred and eat the organic matter. The heat they produce causes the compost temperature to rapidly rise to around 55°C.
2) Thermophilic (high heat) phase, which can last up to several months. This attracts new heat-loving bacteria and organisms which eat the primary consumers. At this heat, most of the nasty pathogens are destroyed, and the pile tends to become quite acidic. As temperatures over 65°C can kill most of the good bacteria and microbes as well, it is important to slow down the decomposition by aerating and mixing the pile.
3) Cooling and curing phase. As the supply of the high-energy compounds becomes exhausted, the temperature gradually drops, and mesophilic microorganisms take over once more for final maturation of the remaining matter.
All types of organisms are quickly attracted to a well-built compost pile. As earthworms feast on the bacteria in the pile during the curing phase, they will further aerate it and create and enhance the diversity of life via their leachate.
What About the Acid Levels?
As we noted above, the pile will turn quite acidic, but mixing it by turning it over regularly during the second phase will solve this problem. One could also add wood ash (which is originally where the word “pot-ash” for potassium comes from) to your pile, which makes it more alkaline.
Although we do like to add a bit of wood ash, we do this more for the essential micro-nutrients contained in the ash. Think of these as the nutrients that a tree was using at the time when it was cut down, and that were not destroyed by burning as part of the carbon or volatile matter content.
Another method to balance the pH of your pile is to add lime, but we don’t think this is necessary, and too much lime can anyhow kill off your organic process.
The Thrive Process
Firstly, we construct a slightly sloping concrete bed of around 2m wide by 12m long, for each of our compost bays. As far as we know, we are the only people who do this. Although it is costly, it has the following benefits:
1. It provides a firm floor for air to flow under the compost pile, whilst separating our precious humus from potential contamination of surrounding areas;
2. Most importantly, when the pile gets wet, the nutrient-rich run-off flows down towards a collection drain, where we scoop it up and pour it back on the pile. We will never pass up on one of Nature’s free gifts.
We then construct an overlapping lattice of thin branches on the floor, around 20-30cm high. This is vital to ensure that oxygen can enter the pile from underneath and ensure aerobic conditions.
Then, bearing in mind that all matter generally has a higher carbon than nitrogen content, we add alternating layers of brown (carbon) and green (nitrogen) material. An easy rule of thumb is to lay down 2 buckets of brown for every 1 bucket of green material. On average, this should get you to the optimal C:N ratio of 25:1. If it’s fresh and wet, consider it as a primary nitrogen (green) source, and if its woodier, consider it as a primary carbon (brown) source.
We also lay in our mineral content as we build the pile e.g., our bone and other bespoke meals. Having built our piles to around 1.5m high, we then leave them for the heating process to begin. Although adding water is useful as the heat starts to build up, it is a good idea to cover the pile to prevent too much rain or other moisture getting in and stalling the process. The reaction is self-sustained by organic acids produced from the composting process, which later become neutralised.
It is vital to turn the piles after some time, to reduce the acid build-up and ensure continued aerobic activity. Turning and mixing also helps to ensure that temperatures don’t go over 65°C and kill off all the beneficial bacteria.
After composting, possibly the two greatest soil enhancements you can offer your plants are inoculated biochar and wood vinegar. These are part of Nature’s building blocks for life as well as her natural immune system.
Secret #1 – Inoculated Biochar
Biochar is essentially charcoal produced in an oxygen-free process under pyrolysis. The best biochar is made from bamboo / reed, oak, and other quality hardwoods, which provide much higher porosity, structural stability, and cation-exchange capacity than softwoods do.
Carbon is the skeletal building block of life, and one teaspoon of powdered biochar contains as much skeletal surface area as an entire football field. It provides a perfect and ever-present host community (or ‘reef’) for all the minerals and microbial life to work their magic in the soil. However, it is vital to never mix dry biochar into your soil, as that would first suck up all the water and nutrients, draining your plants of life, before it starts giving back to them.
Thus, we soak / inoculate our biochar first with essential and indigenous microbes, diluted with water. This has the added benefit of helping to kick-start the soil food web, as well as allowing the plant to talk to the soil to obtain what it needs at the right time. As mentioned, nitrogen is vital for early-stage growth whilst potassium, phosphorous and other macro- and micro- essential minerals and nutrients are needed later.
Using inoculated biochar is a far cheaper, nature-friendly, and regenerative process than blindly throwing chemicals at our plants, hoping that is what is needed for the moment. Biochar provides the perfect host to initially supply microbes and nutrients to a plant. What’s more, as plant roots start to establish a symbiotic relationship with mycelia, biochar provides a ready-built home for the mycelia and root exudates to continually thrive in a loving relationship. It’s no accident that mycelia draw down carbon into the soil for this very purpose. We are simply giving them a helping hand.
We mix our biochar into our compost towards the end of the process, allowing it to settle in and start to establish the living relations. Note that we never sterilise our compost or soils before bagging and selling it. After all, we sell living compost and soils, not dead soils. Please remember that even if the earthworms in our compost have died from having to wait too long in a bag, there is still plenty of life in there, and that worm will provide nutrients too.
One last note on biochar… If you absolutely have to use chemicals on your plants or soil (and we truly hope you don’t) then biochar will help prevent those chemicals from leaching out into vital waterways. Even here, its sponge-like nature will help you get more bang for your chemical buck.
Secret #2 – Wood Vinegar
We have referred to wood vinegar as Nature’s immune system. It occurs naturally after fire and rain, where the distilled gaseous compounds from burning wood fall back onto the plants. We make wood vinegar through pyrolysis and distillation. Perhaps it is like whisky for plants? Known by the Celts as “uisge beatha” and the Romans as “aqua vitae”, it was considered the water of life.
We don’t understand exactly how or why it works but these are some of the currently observed benefits of wood vinegar, diluted in various concentrations of water:
1. Speeds up composting
2. As a soil soak, it enables strong root growth
3. Improves seed germination strike rate
4. Improves photosynthesis ability by darkening leaves
5. Deters pathogenic microbes (organic pesticide and fungicide)
6. Drives higher sugar content in fruits (better tasting)
Some also suggest that wood vinegar can increase the bioavailability of nutrients in soil, improve plant and soil disease resistance, and reduce commercial fertiliser use. This seems to be based on claims that it can stabilise molecular water clusters (H2O)n in plants, leading to what more esoteric folk would call “activated” water. These aspects would also all be wonderful of course, but for us the evidence is not yet conclusive.
The secret to making good wood vinegar is to get the distillation cuts right. We set aside the early “foreshot” as this contains too much tar. Although the Vikings used pine tar to seal their boats, we are pretty sure that living plants would prefer not to be sprayed with it. However, it does make for an excellent outdoor wood preserver. 3
As the temperature rises in the distillation process, we combine the “heads” and the “hearts” of distillation together. Using the right wood here is vital. As the king of trees, the Oak, as well as bamboo and reed, are considered the best candidates. It’s fortuitous that oak and bamboo also make for an excellent biochar.
The final “tails” cut contains most of the lighter aromatic compounds. We are undecided as to whether this should also be included in our wood vinegar, as cannabis growers etc., place such a high premium on getting their terpenes and aromatic levels just right. For now, we keep the tails out, but we remain open to always learning from Nature, and may one day change our minds.
3. In our experimentation we have noted how wood vinegar tar is less absorbed by plant leaves than the heads and hearts. However, dead wood readily absorbs the tar without leaching out over time. Hence it is a great organic alternative to chemical preservative treatment of wood, as well as a pest control. It leaves wood with a relatively pleasant smoky aroma.
Fresh compost is not necessarily a well-aerated soil. Some plants, especially seedlings, need properly aerated soil for their roots to strengthen and grow.
Adding our own mycyelium rich soils and biochar provide a great structural amendment as a start. However, we also favour adding perlite, vermiculite and coco-coir.
It is quite important to understand for what purpose a particular soil is meant for, as we can add more or less of these structural elements accordingly.
Another consideration is that they will affect the cation-exchange capacity of the soil. The final "tuning" of the right soil for the right purpose is not really that vital or necessary for the dedicated amateur grower.