Learning about your garden’s soil – what it actually is, and how to improve it to create a nourishing foundation or your garden – is an excellent way to increase your household’s resilience AND grow your best-ever veggies, both at once.
And it’s dead-easy, once you know the basics.
In the video below (which was a live mini-workshop), you can learn all about the basics of your garden soil – it’s makeup, it’s mysteries, and how you can improve the soil at your place.
In this mini workshop, we first explore the wonderful ecosystem that is soil, with a bit of help from author, organic farmer and also our mate Matthew Evans (whose latest book is SOIL… yep, you can see where we’re going with that one!).
Then, we dive into what actually makes up soil, the different types that you’ll commonly find in your garden, and how to figure out exactly what components make up YOUR soil, so you can improve it, to enhance your garden and grow more nutritious food.
Ok! Here’s the workshop…
Rightio – feeling inspired about the wonders of soil in general, and your garden’s soil in particular?
Once you’ve watched the workshop, check out the resources below – including our awesome Soil Type Calculator – which we made for you so you can de-code your soil’s texture.
And if you’ve got questions? Comment below, and we can help you out. We can’t wait to see you get started on creating your best-ever soil.
Understanding Soil
As Nick said, there are many different perspectives that we can use to examine our soil. You can think of them kind of like ‘lenses’ that you can look at the soil through…
One lens is the structure lens. How soil behaves physically, how it holds together and how it holds onto other things.
Another lens is chemistry. What elements and compounds are in the soil, how they interact with your plants, and how easy they are for your plants to access.
And another lens is the biology. The wonderful world of lifeforms living in your soil, and how you can make them thrive and multiply.
And even all THIS isn’t all there is to soil… but let’s start with the lenses above, to keep things simple.
It’s through ensuring each aspect of your soil is in balance, that you can have truly thriving, healthy soil.
Soil Structure
The structure of your soil determines how the soil physically behaves. This will also influence the soil chemistry and how easy it is for soil biology to multiply and thrive.
In a structural sense there are four main ingredients that determine how soil behaves – like Matthew talked about int he workshop, the biggest part are the mineral solids of sand, silt & clay – they make up nearly half the volume. And only a small part of healthy soil is actually organic matter – this includes all the living things, it’s less than 10% of the volume
The rest of your soil isn’t solid at all – it’s water & air and together they take up about half the volume too. The actual amount of air and water varies quite a lot as you water your garden or it rains, and as it dries back out. This is why it’s incredibly important to avoid compaction in your soil – that water and air are crucial to creating a healthy soil structure.
How your soil behaves structurally is down to the ratio of sand, silt and clay in that ‘mineral solids’ part in the pic above.
Figuring out your soil texture: start with your hands
Before we get to the jar test (which is a great DIY way to find out more about your soil) – start with your hands! Take a bit of your soil, and do a ribbon test. This will reveal how much clay you have in your soil:
Ribbon test how-to – pdfRibbon test how to – video
It’s a REALLY good idea to start with this test, because it will tell you upfront how much clay is in your soil. The jar test below is ace, but there’s *some types* of clay soil that disperse weirdly in water, which might lead you to thinking that you don’t have much clay in your soil, when actually you’ve got heaps. So – do the ribbon test first – it will help your understanding of what comes next.
The jar test
So Nick explains the jar test in the video above, but here’s The Jar Test bit of the video again, incase you missed it. Make sure you take your soil sample from the root zone of your plants – not the very top of the surface. This will give you a more accurate result.
Once you’ve done your jar test, you can move on to the soil type calculator!
Soil Type Calculator
Once you’ve done your jar test, punched the results into the calculator below, and you know what type of soil you have – you can start to figure out how best to support and build up your particular soil.
Knowing your soil type texture will inform all kinds of decisions when you’re getting things growing – from how best to plant your fruit trees, to what you can expect from your veggie beds in a drought year. And no matter what type of soil you have, there’s things you can do to improve it.
Got ‘heavy clay’ soil?
Check if you have ‘dispersive clays’ in your soil, which need a special approach – There’s a video in the calculator page above that explains how to test if you do – go have a watch.
A note about ‘claybreaker’ – if you have heavy clays, you might see info around recommending that you add gypsum, otherwise known as ‘claybreaker’, to help amend your soil structure. As with any inputs – read carefully before applying! Too much is not a good thing. Also, gypsum will NOT work in most dispersive clays – which is why figuring out if your clays are dispersive first is an excellent idea.
Using cover crops that also have tap roots can be a great way to improve heavy clay soils – here’s a great video from Sarvodaya Institute about using Daikon (and other things) to help improve soil structure (and biology, and everything else).
Soil Chemistry
The next lens you can use to look at your soil is the Chemistry lens. The chemistry of the soil affects the structure and the biology of your soil. You might already be familiar with with the ‘big three’ plant nutrients – Nitrogen, Phosphorus & Potassium (sometimes shortened to NPK)
But calcium, magnesium and sulphur and their compounds are also important nutrients and can dramatically affect soil structure. And then there is Zinc, Boron, Manganese, Iron & (Nick’s favourite) Molybdenum!
These are the major ones, but there are many many more and then thousands of compounds of these elements that make up a dizzying array of nutrients & just like US, the plants, animals & microbes that live in your soil need a wide range of these nutrients to thrive.
Thankfully you don’t need to know exactly how many of each of these elements and their compounds are in your soil! But it’s good to understand that they are there.
Why does all this matter? Because your soil’s chemistry deeply affects the health of the soil food web. Your soil’s chemistry also affects what kinds of nutrients your garden plants have access to – so if there’s great and useful nutrients in your soil, but the chemistry is out of whack – your plants won’t be able to access that nourishment Which means less nutrient-dense harvests for YOU.
This is why some basic soil testing can be a good idea, if you’re worried about your soil’s chemical balance, OR if you have reason to suspect that your soil might have some nasties in it, like heavy metals. The best place to start is with a simple pH test.
Testing your soil’s pH
So if you just do one test on your soils chemistry, do this one. You can do a pH test easily at home, and once you understand the results, you can take steps to help ensure nutrients are available to your plants and biology, and that any heavy metals that are in your soil have less impact.
Make sure you take your soil sample from the root zone of your plants – not the very top of the surface. This will give you a more accurate result. As we explain in the article below, taking a few samples from your veggie patch, rather than just one sample, will give you broader accuracy.
How to do a pH test on your Garden Soil (and what to do with your results)
As Nick said in the workshop, soil nutrients become locked up in really alkaline soils, and metals dissolve and become soluble poisons in very acidic soils. So neither of these are ideal for your garden. Either way, most plants won’t grow really well unless your soils are somewhere in the middle 7.5 – 5.5 pH, which is considered the most neutral.
Testing your soil for heavy metals (and other things)
There’s a lot of great places that you can send a sample of your soil to get it tested for… whatever you want, really. The different testing labs range in price, and some of the results that they send back will be easier to read than others. There’s soil testing labs in most countries, so find one near you. The two we’ve used in Australia (there’s also other good ones) are:
Vege Safe – a community science project that tests your soil, while adding to their databankSWEP – good soil and water testing lab in Naarm / Melbourne – if you don’t understand your test results, they’ll talk you through them.Wherever you are – a search on ‘soil testing lab’ should yield an option that you can access. Also, ask at your closest agricultural supply store (even if that’s not exactly local to you) – they should be able to point you at available soil testing.
A few resources for increasing and supporting your soil’s chemical balance
Using Seaweed in your Garden – including garden fertilizersGreen Manures – what they are, and how to use themWorm Farms – a guide to getting startedCompost – a great beginner’s guide
Soil Biology
The final lens by why we can look at our soil is biology. Why is soil biology so important? Well, apart from being an amazing ecosystem which is crucial to addressing the climate crisis, the biology in your soil…
Helps build better soil structureHelps balance your soil’s chemistryBuilds humus (the good stuff!)Holds carbon in your soil (which helps the planet, and everyone on it)Helps hold on to nutrients, to make them more available for your plants.
You might think of soil biology in terms of the things you can see, like earth worms. But, in fact, there is a dizzying array of different creatures down there… a wild and diverse ecology that rivals the most complex ecosystems on earth… and it’s right beneath our feet!
There are nematodes and arthropods, bacteria, protozoa and our favourite, the fungi.
Above is a pic of Dr Elaine Ingham – though her organisation The Soil Food Web, Dr Ingham is a soil science leader – she has made it her life’s work to help farmers (and the rest of us) understand of the importance of life in the soil.
Not sure what we mean about all this soil life? Well –
Here’s a video of a protist, bulldozing its way through soil and aerating as it goes…Here’s a video of Bacteria moving along hyphae on the ‘Fungal Highway’ that exists in healthy soil, between different plants.
Improving and supporting your soil’s biology
So you want to support your soil’s biology. Is it worth adding specific biology, like bacteria, protozoa, worms or fungi? Well, maybe. But you’re better off starting by ensuring your soil conditions support your existing soil microorganisms by:
Looking after your soil structure by keeping you soil aerated, not compactedKeeping your soil moist, not wetKeeping living things feeding your soil (ie lots of plants)Avoiding any nasty chemicalsAnd feeding your soil with a diverse range of different types of organic matter (including compost)
If you get really enthused, you can add biology (or inoculate) your soils with Actively Aerated Compost Teas, but making them is not a simple process (though you can try!) – and that process starts with making really great compost.
So often it’s easiest to inoculate you garden with good-quality compost directly… compost will add microorganisms & the nutrients & food that they need, all in one hit.
A few resources for increasing and supporting your soil’s biology
Using Seaweed in your Garden – including garden fertilizersGreen Manures – what they are, and how to use themWorm Farms – a guide to getting startedCompost – a great beginner’s guide
Milkwood’s Seven Tips for Healthy & Resilient Garden Soil:
To wrap all this knowledge up, here’s what we think are the most effective ways to create heathy soil at your place:
Enhance your soil’s structureCheck & adjust your soil chemistry as neededKeep the soil moistKeep the soil covered (mulch! Or plants. Or both!)Minimise compaction & disturbance wherever possibleMaximise diversity & keep your soil food web happy with lots of plantsAdd a diverse range of organic matter to your soil (go the compost)
Great all-round SOIL books + resources to get you started
As we said at the start of this article – SOIL isn’t just it’s structure, chemistry and biology… there’s all sorts of other knowledges and understandings of what soil is, and how we can co-habitate with this amazing ecosystem that extends into us, and into everything we share this world with. There’s a lot to think about here, so here’s a few titles to get you started
SOIL – Matthew EvansPapatuanuku, Earth Mother: indigenous knowledge in 21st century soil management – Robert McGowanTeaming With Microbes – Jeff Lowenfels, Wayne LewisSoil, not Oil – Vandana ShivaThe Intelligent Gardener: Growing Nutrient Dense Food – Steve SolomonBraiding Sweetgrass: Indigenous Wisdom, Scientific Knowledge, and the Teachings of Plants – Robin Kimmerer For the Love of Soil – arts / science / edu org doing rad things
Got suggestions for other reads that should be on this list? Let us know!
And of you don’t have a garden? (or even if you do, actually)
Always keep in mind that you can support healthy soils, both near you and further away, by eating a wide range of plants and supporting local growers who take good care of their soil.
By doing these things, you are supporting your own health, your local soil’s health, and caring for your community too, by supporting local food systems.
This workshop was an extended lesson from one of the many subjects that we teach inside our online course, Permaculture Living. If you’re curious, you can check the course out here.
Thank you soil, for all that you do! Also thanks to everyone who came along to this workshop live, it was GREAT to have you all there. Join our newsletter if you’d like to hear about future workshops.
Also big thanks to Matthew Evans, author of SOIL, for chatting to Nick about the good stuff. You can get Soil – The incredible story of what keeps the earth, and us, healthy in book form and in Audiobook form also.
Got questions?
No worries – leave a comment below and we can answer whatever you’re wondering. Good luck with building healthy soil!
We acknowledge that permaculture owes the roots of its theory and practice to traditional and Indigenous knowledges, from all over the world. We all stand on the shoulders of many ancestors – as we learn, and re-learn, these skills and concepts. We pay our deepest respects and give our heartfelt thanks to these knowledge-keepers, both past and present.
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