In our first two articles, we discovered the incredible world living beneath our feet and how bacteria, fungi, earthworms and plant roots work together to support our vegetables.
Today, I want to bring all of that back into our own gardens. Because here’s something I’ve learned over the years: sometimes the best thing we can do for our soil is to stop interfering with it quite so much! We spend so much time feeding, digging, watering, spraying and trying to fix things that we sometimes forget there’s an entire living ecosystem already doing an extraordinary amount of work for us.
So how do we encourage that underground world to thrive?
Stop turning your soil upside down!
I know this might sound strange, especially if you grew up watching someone dig over their vegetable beds before every planting season. For years, gardeners were taught that the first step to preparing a garden was to grab a spade and turn everything over. But soil isn’t simply a pile of loose material. It has structure, layers, tiny air pockets, fungal networks and countless organisms living at different depths.
When we repeatedly dig and turn the soil, we disturb that structure, expose buried organic matter to oxygen and can damage fungal networks and earthworm tunnels. This is one of the reasons I love no-dig gardening. Instead of turning over the entire bed, we add compost to the surface, cover exposed areas with mulch and allow roots, earthworms and other organisms to help maintain the soil structure.
Here’s an interesting fact: earthworms can create permanent or semi-permanent burrows that help water move deeper into the ground. Some species even pull fallen leaves into their tunnels to feed on them. Imagine spending your day building little underground drainage systems while also recycling garden waste! Of course, there are times when digging is necessary, especially when establishing a new garden or dealing with severe compaction. But once a bed is established, less disturbance can often be beneficial.
Your soil doesn’t like being naked!
If there’s one thing I wish every vegetable gardener would do, it’s to stop leaving their soil exposed. Think about our summers. We can have beautiful sunny days, but that same sun can heat bare soil considerably, especially in raised beds and containers. And when soil is exposed to wind and direct sunlight, moisture can disappear surprisingly quickly.
A layer of mulch acts almost like a protective blanket. It helps reduce evaporation, moderates temperature fluctuations and protects the surface from the impact of heavy rain or irrigation. But here’s the fascinating part. Mulch isn’t only protecting your soil. As organic mulch breaks down, it also becomes food for the organisms living beneath it. Earthworms, fungi and other decomposers gradually process that material, helping return nutrients to the soil. In my garden, I use materials such as dry leaves, straw and other suitable organic matter. I prefer to keep a layer over exposed soil, topping it up as it decomposes.
A practical tip: start with roughly 5 cm of loose organic mulch around established vegetables, keeping it slightly away from plant stems. Very fine materials may need a thinner layer to avoid matting. And remember that newly sown seeds need special attention. A thick layer of mulch can make it difficult for tiny seedlings to emerge.
Compost is more than just plant food
We often think of compost as something we add because our vegetables need nutrients. And yes, mature compost can provide nutrients, although the amounts vary depending on what went into it. But compost does something else that’s just as important. It adds organic matter, which can improve soil structure, support water retention in sandy soils and help create better conditions for soil organisms.
Here’s something worth knowing: organic matter can help both sandy and clay soils, but in different ways.
In sandy soil, it can improve water and nutrient retention. In clay soil, it can help encourage better aggregation and structure over time. That’s one reason compost is such a useful addition to many different gardens. At VanZylStead, we use several methods of recycling organic material, including composting and worm farming. I love knowing that kitchen scraps, fallen leaves and garden trimmings can eventually find their way back into our growing beds.
But please remember that more isn’t always better. Adding excessive amounts of manure-based compost year after year can lead to nutrient imbalances, particularly phosphorus build-up. Compost should be mature, and it’s worth paying attention to how much you’re adding.
Did you know that your soil needs to breathe?
This is something gardeners sometimes overlook. We know plants need water, but their roots also need oxygen. Healthy soil contains spaces between its particles. Some of those spaces hold water, while others contain air. When soil becomes waterlogged, those air spaces fill with water, making it difficult for roots and many beneficial organisms to obtain enough oxygen. That’s why a plant can wilt even when the soil is soaking wet! The roots may be struggling to function properly, and adding more water only makes the situation worse.
Here’s a little garden test: Before watering, push your finger a few centimetres into the soil. If it still feels moist, your plants may not need another drink just yet. For deeper-rooted vegetables, also check moisture further down rather than relying only on the surface. And if water sits on top of your beds for long periods, investigate drainage and compaction instead of simply changing your fertiliser.
Walking on your garden beds can cause more damage than you think
Have you ever noticed how hard the soil becomes in areas where people regularly walk? That’s compaction. When soil particles are pressed tightly together, the spaces available for air, water and roots become smaller. Roots may struggle to penetrate the soil, water may run off rather than soak in, and some soil organisms can find the conditions less suitable. This is why I love raised beds and permanent pathways. Once you’ve established your beds, try to avoid stepping into them. You want your growing soil to remain loose and well structured.
And here’s a useful tip: avoid working or walking on soil when it’s very wet, particularly clay-rich soil, because it is more vulnerable to compaction.
Your soil needs living roots, too!
Now, here’s something that might surprise you. Even when you’re not harvesting vegetables, living plants can still contribute to the health of your soil. Remember those root exudates we spoke about in Part 2? Living roots release carbon-rich compounds that support communities of microorganisms around them. When a bed remains empty for a long time, that supply of root-derived food is reduced.
This is one reason cover crops can be so valuable. Instead of leaving a bed completely bare between growing seasons, you can grow suitable cover crops to protect the soil, support microbial activity and, depending on the species, contribute organic matter or help manage nutrients. Legumes such as certain clovers and vetches can also fix atmospheric nitrogen when the appropriate bacteria are present. But cover crops aren’t always practical in small vegetable gardens, especially when water is limited. Sometimes simply keeping a variety of vegetables and herbs growing throughout the year is a good way to maintain living roots in your beds.
What about pesticides and fertilisers?
This is where I think we need to be a little more thoughtful. Not every garden product is harmful to soil life, and not every organic product is automatically harmless. The effects depend on the product, how much is applied, how often it’s used and the organisms exposed to it. For example, some broad-spectrum insecticides can affect beneficial insects, while excessive fertiliser applications can alter soil chemistry and create problems for roots and microorganisms.
Even certain organic pesticides can affect non-target organisms. My preference is always to start with prevention, observation and good garden management. Encourage beneficial insects, remove diseased material where appropriate, maintain healthy soil and only use pest-control products when there’s a genuine need.
And always follow the label instructions.
Five little habits that make a big difference
You don’t need to completely redesign your garden to start caring for your soil differently.
Here are five habits I would encourage every vegetable gardener to adopt:
Keep your soil covered. Use organic mulch to protect it from heat, wind and moisture loss.
Add mature compost regularly, but sensibly. Build organic matter without overloading the soil with nutrients.
Disturb the soil as little as practical. Protect its structure and the organisms living within it.
Water according to the soil’s needs. Aim for good moisture without leaving roots waterlogged.
Keep something growing when possible. A variety of living roots can help support a diverse underground ecosystem.
None of these habits is particularly complicated, but together they can make a meaningful difference over time.
Here’s something I want you to try this weekend
Choose two areas of your garden. Perhaps one bed has been mulched and regularly topped up with compost, while another has been left exposed. Take a small handful of soil from each and compare them. Look at the colour, texture and structure. Does one crumble more easily? Can you see organic matter or signs of earthworm activity? After watering, notice how quickly the water soaks in and how long the soil stays moist.
You might be surprised by the differences. Just remember that one observation doesn’t tell the whole story. Soil type, weather and previous management all influence what you see. But the more you observe your soil, the better you’ll become at understanding what it needs.
A final thought from my garden
When we started growing food at VanZylStead more than eleven years ago, I was so focused on what was happening above ground. I wanted healthy tomatoes, beautiful carrots and productive vegetable beds.
And of course, I still do! But over the years, I’ve learned to pay just as much attention to what’s happening beneath the surface. Because healthy soil isn’t something we can create overnight with one bag of compost or a bottle of fertiliser. It’s something we build and care for over time. Every layer of mulch, every handful of mature compost, every root left to decompose and every season of thoughtful gardening contributes to the bigger picture.
And perhaps that’s the biggest lesson from our Secret Life of Soil series. We aren’t simply growing vegetables in soil. We’re growing vegetables with the help of an entire living ecosystem. The more we understand that relationship, the better gardeners we become.
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