 | Imagine this: you dig a spade into your garden, and to your absolute amazement it sinks into soft, deep, rich soil! I know, I mean this is Canberra right? But here’s the thing - it is totally possible. Yup, even here in the land of clay. Growing soil is what gardeners want, because it means increasing fertility. That means bigger, healthier fruit and veg, or more glorious flowers. But it’s also a sign of something even more important that runs counter to much of our culture and habits. I’d even suggest it’s completely radical… |
A recent excavation for a wider access path revealed to us just how much top soil depth we have created over the past 7-8 years in this part of the garden. Definitely deeper than one spade! Note that we started with nothing but pale grey subsoil - shown in bottom of picture.
That something is this: you can be regenerative, rather than extractive, in how you grow food.
The funny thing is it doesn't sound all that radical when I write it down like this. Just common sense really. After all, I’m sure most of us have visited places where the soil has been improved and deepened through a gardener’s love (and a lot of compost) over time.
However, I want to pause on this for a moment, because in our modern capitalist way of doing things it runs quite counter to the way things are normally done. The aim of a capitalist economy is to extract as much value as we possibly can from something, so that we can make as much profit as possible. There is little incentive to put money back in, except that which is used to help the enterprise itself grow. (Before you point this out, I realise there are heaps of organisations and enterprises that don’t put profit above all else - but they don’t tend to be the richest and most powerful. So, it’s not that you can’t survive in a capitalist system if you want to be caring and regenerative, but it is true that the most caring and regenerative of businesses aren’t running on huge profit margins. But I digress.)
In modern agriculture we hear about soil degradation, erosion, mining of the soil. There are claims that the world has only 60 years of harvests (or good topsoil) left. But the modelling used to make such assertions assumes that growing food is necessarily an extractive and depleting activity. Yet, as many home gardeners know, growing food does not have to be extractive - we can grow the soil and food at the same time.
I know that back gardening is really small scale. Some would argue it is impossible to do what gardeners do at a large scale, though regenerative agriculture practitioners would disagree. Either way, on a personal level it's incredibly good for our souls to know that sometimes our human actions can be regenerative and healing to nature, and not exploitative or always bad.
Sometimes it even happens quite unintentionally! Nature does this already. If it weren't for the amazing ability of plants to harvest the sun’s energy, turn it into biomass which in turn is used by microbes to build soil and fertility over time, there would be no complex life at all on this brilliant and beautiful planet. But with a little bit of strategic planning and intervention, we gardeners can even help grow soil depth and fertility faster than it would naturally.
So, how do we do that?
1. Composting and amending
No surprises here, but composting kitchen scraps, clippings, leaves, small prunings and so on is a pretty common practice for avid food gardeners like us. When we first created this new vegetable bed, we looked around for whatever we could to start to build up organic matter. I remember adding heaps of autumn leaves to the newly made bed - we have a Chinese elm in the front garden which has small leaves that break down quite quickly and I used barrow loads of them. I didn't even bother composting them first - I just mixed them in with some of the remaining clay, a bit of compost, and periodically some horse poo. We are fortunate to live close to the Cook horse paddocks. Every now and then a large pile of horse manure is dumped at the side of the car park. Rather than letting this nutrient rich stuff go to waste dispersing its nutrients over the car park where they are not needed or wanted, we take a few barrow loads home and add to vegetable beds as needed. More recently I got a big pile of fresh chippings (basically whatever an arborist mulches after cutting down trees) which were liberally distributed overf the whole garden, including this bed. So over a few years, the bed has benefited from adding a fair bit of extra stuff that was otherwise going to waste. However, this process involved bringing things from off site into our garden, so if you were being picky, you could certainly argue that this isn't a case of 'growing' the soil, but rather building it with external inputs. Thinking about this more systemically, its a case of moving nutrients (organic matter in this case) from one location to another, not growing organic matter in place. But we can also grow the soil in place as well - as described in the next section.
2. Growing fertility in place
Healthy soil is alive. The natural lifecycles of plants gradually creates soil - think of deciduous trees dropping their leaves each autumn, or countless generations of annual plants living and dying, all of which provides food for all sorts of life which, over time, decays, digests and converts organic matter into humus. This is why the soil beneath old-growth forests can be fantastic. Interestingly, there are plenty of soil microbes which also feed on sugars that are provided by the roots of plants - this means that soils stay healthiest when plants are grown in the soil year round - you can remind yourself of this the next time you worry about having too many weeds in a spot, those weeds might be unsightly, but they are keeping your soil healthy.
Perennial plants are great for feeding the soil, as they live for many years, but in an annual vegetable bed they aren’t practical. Instead we have regularly planted nitrogen-fixing species into the beds - nitrogen fixers (also called legumes) harvest nitrogen from the atmosphere to boost their growth. As such, they are often some of the first species to recolonise cleared or damaged land. Once these nitrogen fixing plants die, they provide nitrogen-rich biomass to rot down and increase the overall nitrogen levels in the soil for the next plants to grow there.
So, in our little vegetable bed we have aimed to grow legumes regularly - climbing and dwarf beans in summer, and broad beans or peas in the winter. Here in Canberra you can’t really get better than the humble broad bean. While we eat the beans, the remainder of the plant is excellent as a source of bulk organic matter - it grows quite big and those stems are pretty sturdy. When the plants are finished, we tend to chop the plants at the base (leaving the roots intact within the soil, where they break down gradually, creating little tunnels that help rain soak in more easily). We then chop up the spent plants, and drop these chopped pieces over the ground, to rot down in place.
Part of the approach with cutting plants off at the base, rather than pulling them out, is to reduce tillage of the soil. Traditional tilling disrupts soil structure and harms beneficial organisms. No-till gardening, on the other hand, promotes the natural processes within the soil. By leaving the soil undisturbed, you allow earthworms, microbes, and other beneficial creatures to thrive. This method encourages the formation of healthy soil aggregates and improves overall soil fertility. With vegetable gardening there is always some need for tillage when swapping out one crop for the next and to reduce weeds around your crop, but our general approach is to minimise this and cut spent plants back at the base, leaving their roots to rot in the ground, rather than pulling them out wherever possible.
Our vegetable bed has therefore benefited from two main approaches which has resulted in a good layer of rich soil in this spot over several years. In nature, it's believed that a few cm of topsoil takes about 1000 years to grow. Clearly in our bed, by adding in extra material, through plant selection and chopping spent plants up to help them break down faster, we have speeded up this process quite a lot. However, there is one more aspect to growing soil and fertility that I believe has been very helpful for us, and it is often overlooked.
That is the role of water.
The funny thing is it doesn't sound all that radical when I write it down like this. Just common sense really. After all, I’m sure most of us have visited places where the soil has been improved and deepened through a gardener’s love (and a lot of compost) over time.
However, I want to pause on this for a moment, because in our modern capitalist way of doing things it runs quite counter to the way things are normally done. The aim of a capitalist economy is to extract as much value as we possibly can from something, so that we can make as much profit as possible. There is little incentive to put money back in, except that which is used to help the enterprise itself grow. (Before you point this out, I realise there are heaps of organisations and enterprises that don’t put profit above all else - but they don’t tend to be the richest and most powerful. So, it’s not that you can’t survive in a capitalist system if you want to be caring and regenerative, but it is true that the most caring and regenerative of businesses aren’t running on huge profit margins. But I digress.)
In modern agriculture we hear about soil degradation, erosion, mining of the soil. There are claims that the world has only 60 years of harvests (or good topsoil) left. But the modelling used to make such assertions assumes that growing food is necessarily an extractive and depleting activity. Yet, as many home gardeners know, growing food does not have to be extractive - we can grow the soil and food at the same time.
I know that back gardening is really small scale. Some would argue it is impossible to do what gardeners do at a large scale, though regenerative agriculture practitioners would disagree. Either way, on a personal level it's incredibly good for our souls to know that sometimes our human actions can be regenerative and healing to nature, and not exploitative or always bad.
Sometimes it even happens quite unintentionally! Nature does this already. If it weren't for the amazing ability of plants to harvest the sun’s energy, turn it into biomass which in turn is used by microbes to build soil and fertility over time, there would be no complex life at all on this brilliant and beautiful planet. But with a little bit of strategic planning and intervention, we gardeners can even help grow soil depth and fertility faster than it would naturally.
So, how do we do that?
1. Composting and amending
No surprises here, but composting kitchen scraps, clippings, leaves, small prunings and so on is a pretty common practice for avid food gardeners like us. When we first created this new vegetable bed, we looked around for whatever we could to start to build up organic matter. I remember adding heaps of autumn leaves to the newly made bed - we have a Chinese elm in the front garden which has small leaves that break down quite quickly and I used barrow loads of them. I didn't even bother composting them first - I just mixed them in with some of the remaining clay, a bit of compost, and periodically some horse poo. We are fortunate to live close to the Cook horse paddocks. Every now and then a large pile of horse manure is dumped at the side of the car park. Rather than letting this nutrient rich stuff go to waste dispersing its nutrients over the car park where they are not needed or wanted, we take a few barrow loads home and add to vegetable beds as needed. More recently I got a big pile of fresh chippings (basically whatever an arborist mulches after cutting down trees) which were liberally distributed overf the whole garden, including this bed. So over a few years, the bed has benefited from adding a fair bit of extra stuff that was otherwise going to waste. However, this process involved bringing things from off site into our garden, so if you were being picky, you could certainly argue that this isn't a case of 'growing' the soil, but rather building it with external inputs. Thinking about this more systemically, its a case of moving nutrients (organic matter in this case) from one location to another, not growing organic matter in place. But we can also grow the soil in place as well - as described in the next section.
2. Growing fertility in place
Healthy soil is alive. The natural lifecycles of plants gradually creates soil - think of deciduous trees dropping their leaves each autumn, or countless generations of annual plants living and dying, all of which provides food for all sorts of life which, over time, decays, digests and converts organic matter into humus. This is why the soil beneath old-growth forests can be fantastic. Interestingly, there are plenty of soil microbes which also feed on sugars that are provided by the roots of plants - this means that soils stay healthiest when plants are grown in the soil year round - you can remind yourself of this the next time you worry about having too many weeds in a spot, those weeds might be unsightly, but they are keeping your soil healthy.
Perennial plants are great for feeding the soil, as they live for many years, but in an annual vegetable bed they aren’t practical. Instead we have regularly planted nitrogen-fixing species into the beds - nitrogen fixers (also called legumes) harvest nitrogen from the atmosphere to boost their growth. As such, they are often some of the first species to recolonise cleared or damaged land. Once these nitrogen fixing plants die, they provide nitrogen-rich biomass to rot down and increase the overall nitrogen levels in the soil for the next plants to grow there.
So, in our little vegetable bed we have aimed to grow legumes regularly - climbing and dwarf beans in summer, and broad beans or peas in the winter. Here in Canberra you can’t really get better than the humble broad bean. While we eat the beans, the remainder of the plant is excellent as a source of bulk organic matter - it grows quite big and those stems are pretty sturdy. When the plants are finished, we tend to chop the plants at the base (leaving the roots intact within the soil, where they break down gradually, creating little tunnels that help rain soak in more easily). We then chop up the spent plants, and drop these chopped pieces over the ground, to rot down in place.
Part of the approach with cutting plants off at the base, rather than pulling them out, is to reduce tillage of the soil. Traditional tilling disrupts soil structure and harms beneficial organisms. No-till gardening, on the other hand, promotes the natural processes within the soil. By leaving the soil undisturbed, you allow earthworms, microbes, and other beneficial creatures to thrive. This method encourages the formation of healthy soil aggregates and improves overall soil fertility. With vegetable gardening there is always some need for tillage when swapping out one crop for the next and to reduce weeds around your crop, but our general approach is to minimise this and cut spent plants back at the base, leaving their roots to rot in the ground, rather than pulling them out wherever possible.
Our vegetable bed has therefore benefited from two main approaches which has resulted in a good layer of rich soil in this spot over several years. In nature, it's believed that a few cm of topsoil takes about 1000 years to grow. Clearly in our bed, by adding in extra material, through plant selection and chopping spent plants up to help them break down faster, we have speeded up this process quite a lot. However, there is one more aspect to growing soil and fertility that I believe has been very helpful for us, and it is often overlooked.
That is the role of water.
3. Speeding up the process
Our back garden is on a natural slope. All slopes shed some water in rain, and the heavier the rain, the more runoff there will be. This is why land on slopes is drier than land at the bottoms of valleys. Water also carries nutrients, which is also why the flat bottoms of valleys are also usually more fertile than the steeper land surrounding them.
To counter the effects of the slope, when we made our garden beds, we tried to make them as level as possible, and this bed was no exception. The edge of the bed you see in the picture above is particularly pronounced because it forms a level terrace above it.
When you make your vegetable beds level, it is much easier to water them with a hose, and rain will mostly soak in.
However there is more. Immediately upslope of this particular bed is a paved sitting area, which is slightly sloped so that water sheds off this area and into the garden bed. The paved area is about twice the size of the vegetable bed - if all the rain that falls on the paving ends up in the bed, this is the effect of tripling the annual rainfall on that particular bed. In addition, the downslope side of the bed is part of a swale system we have in the back garden that harvests driveway runoff and tank overflow, so this also creates additional moisture in the area.
Why is having water so important?
It speeds things up in the soil - more moisture allows for more efficient breakdown of plant matter into compost. (If you've ever suffered with a too-dry compost heap you will know what I mean - dry compost just sits there, it takes ages to break down!) Earthworms prefer a cool, moist habitat, so we are creating conditions for them to thrive in. Moist soil also helps our vegetables to grow bigger and faster, thereby creating more biomass to add back to the soil at the end of the season than would be produced in a drier garden.
So, adding water into the equation is the effect of supercharging the natural soil creation process.
The benefits of growing soil extend beyond the garden. Healthy moist soil captures and retains carbon, helping mitigate climate change. Organic rich soil also holds onto water better, like a big sponge. Plants grown in rich, healthy soil are more resilient to pests and diseases, resulting in better yields for you.
Returning to my initial point about being regenerative, perhaps the most useful thing about soil is that it's a really helpful test to see how things are going. If your vegetable beds sink down and lose volume year after year, then this would suggest depletion is occurring. That is, more is being extracted from the garden than is growing or being put back in. On the other hand, if you find your soil getting richer, deeper, and more fertile with each passing season, then you are experiencing first hand what regeneration looks like. Woo hoo - that experience is good for both soil and soul!
Growing soil is a journey, not a destination. It requires patience, observation, and a willingness to learn from nature. Sometimes it only takes a few small tweaks to set your garden from a state of degradation into one of regeneration. Remember, Cally's always available to provide advice and guidance if you feel you need a bit of help getting things started. That's what our garden consultation service is for!
As you nurture your soil, you'll find a deeper connection to your garden and a greater appreciation for the intricate web of life beneath your feet. So, the next time you admire your flourishing garden, remember that its true success starts with the soil—and you are the steward of its growth.
And, if you find your soil is indeed growing, pause and reflect on the fact that you are already helping to heal and regenerate the land. Go you!
Happy gardening!
Our back garden is on a natural slope. All slopes shed some water in rain, and the heavier the rain, the more runoff there will be. This is why land on slopes is drier than land at the bottoms of valleys. Water also carries nutrients, which is also why the flat bottoms of valleys are also usually more fertile than the steeper land surrounding them.
To counter the effects of the slope, when we made our garden beds, we tried to make them as level as possible, and this bed was no exception. The edge of the bed you see in the picture above is particularly pronounced because it forms a level terrace above it.
When you make your vegetable beds level, it is much easier to water them with a hose, and rain will mostly soak in.
However there is more. Immediately upslope of this particular bed is a paved sitting area, which is slightly sloped so that water sheds off this area and into the garden bed. The paved area is about twice the size of the vegetable bed - if all the rain that falls on the paving ends up in the bed, this is the effect of tripling the annual rainfall on that particular bed. In addition, the downslope side of the bed is part of a swale system we have in the back garden that harvests driveway runoff and tank overflow, so this also creates additional moisture in the area.
Why is having water so important?
It speeds things up in the soil - more moisture allows for more efficient breakdown of plant matter into compost. (If you've ever suffered with a too-dry compost heap you will know what I mean - dry compost just sits there, it takes ages to break down!) Earthworms prefer a cool, moist habitat, so we are creating conditions for them to thrive in. Moist soil also helps our vegetables to grow bigger and faster, thereby creating more biomass to add back to the soil at the end of the season than would be produced in a drier garden.
So, adding water into the equation is the effect of supercharging the natural soil creation process.
The benefits of growing soil extend beyond the garden. Healthy moist soil captures and retains carbon, helping mitigate climate change. Organic rich soil also holds onto water better, like a big sponge. Plants grown in rich, healthy soil are more resilient to pests and diseases, resulting in better yields for you.
Returning to my initial point about being regenerative, perhaps the most useful thing about soil is that it's a really helpful test to see how things are going. If your vegetable beds sink down and lose volume year after year, then this would suggest depletion is occurring. That is, more is being extracted from the garden than is growing or being put back in. On the other hand, if you find your soil getting richer, deeper, and more fertile with each passing season, then you are experiencing first hand what regeneration looks like. Woo hoo - that experience is good for both soil and soul!
Growing soil is a journey, not a destination. It requires patience, observation, and a willingness to learn from nature. Sometimes it only takes a few small tweaks to set your garden from a state of degradation into one of regeneration. Remember, Cally's always available to provide advice and guidance if you feel you need a bit of help getting things started. That's what our garden consultation service is for!
As you nurture your soil, you'll find a deeper connection to your garden and a greater appreciation for the intricate web of life beneath your feet. So, the next time you admire your flourishing garden, remember that its true success starts with the soil—and you are the steward of its growth.
And, if you find your soil is indeed growing, pause and reflect on the fact that you are already helping to heal and regenerate the land. Go you!
Happy gardening!
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