Healthy plants don’t grow alone. Beneath every thriving garden is a living world of microbes, roots, fungi, organic matter, and tiny creatures working together to build resilient soil, support biodiversity, and steward water well.
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If your plants look tired, stressed, or less productive than they should, the answer may not be another fertilizer or a different variety.
It may be what’s happening below ground.
I have had to learn this lesson more than once. One of my former gardens sat where an old swimming pool had been filled in. The soil was compacted and difficult to work, and my shovel often collided with heavy clay, large rocks, and chunks of blue-painted concrete.
But the bigger problem was that it was no longer hospitable to the life that makes healthy soil function.
To garden there, I had to make the soil welcoming to life. I added organic matter, protected the surface with mulch, disturbed it as little as possible, and kept roots growing.
Over time, the goal is to create a garden that depends less on our constant intervention because plants, roots, soil organisms, organic matter, air, and water begin working together.
The goal of nurturing soil ecology is not a perfect garden. The goal is a stronger, more self-renewing one.
In this article:
- What is living soil?
- Feed living soil with compost
- Disturb the soil less
- Leave healthy roots in place
- Keep something growing
- Keep the soil covered
- When living soil needs extra support
- How to know if your soil is improving
What is living soil?
Living soil is a biologically active system in which roots, fungi, bacteria, organic matter, and other soil organisms interact.
Soil structure helps make those relationships possible. The spaces between soil particles do more than hold air and water. They also create habitat for roots, fungal threads, bacteria, and other soil organisms. When soil is loose and crumbly, there is room for this underground community to breathe, feed, and interact.
Much of this activity is concentrated around plant roots. Roots release sugars and other compounds that feed soil organisms. In return, bacteria and fungi help break down organic matter, cycle nutrients, improve access to water and minerals, and contribute to soil structure. Mycorrhizal fungi form especially close partnerships with roots, extending their reach for water and minerals while receiving sugars from plants in return.
This is why living soil is about more than fertility. Adding fertilizer may supply nutrients, but it doesn’t necessarily build the biological relationships or soil structure that allow a garden ecology to become stronger over time.
Plant diversity contributes, too. Different plants produce different roots, feed different soil organisms, and return different kinds of organic matter to the soil. Biodiversity above ground helps nourish biodiversity below ground.
When these relationships are supported, we begin to see qualities associated with healthy soil: better water infiltration, more stable moisture, improved nutrient cycling, and plants that are better able to handle stress.
Fortunately, you don’t have to understand everything happening underground to support it. Start with these five practices.
Homemade compost leverages organic waste to make a microbially rich amendment.
1. Feed living soil with compost
Compost feeds soil life while improving the structure and organic matter that create its habitat.
Rather than being simply a fertilizer, compost helps improve the environment in which roots and soil organisms live. It can improve soil structure, help balance moisture, and feed the soil food web.
Top-dress garden beds with compost in spring or fall, or add it whenever a bed needs refreshing. Repeated applications are especially helpful in soil that has been compacted, neglected, or stripped of organic matter.
Homemade compost closes an important garden loop, turning leaves, plant trimmings, kitchen scraps, and other organic materials into future fertility.
If you are trying to improve difficult soil, compost is the amendment I would start with.
Here are six ways to build a compost bin.
2. Disturb the soil less
Reducing soil disturbance protects the fungal networks, soil aggregates, earthworm channels, and habitat that are already developing underground.
Instead of treating soil like something that needs to be turned and reset every season, think of it as habitat.
Create permanent garden beds and avoid walking on them. When compaction is a problem, use a digging fork or broadfork to gently loosen the soil without flipping it over. Here is the digging fork that I use.
When starting a new bed, you might aerate severely compacted soil first and then sheet mulch with cardboard, compost, and other organic materials rather than digging everything up.
No-till gardening is not really about doing nothing. It is about protecting the soil ecology nature is already building.
3. Leave healthy roots in place
When a healthy crop is finished, cut it at soil level rather than pulling it out.
As the old roots decompose, they feed soil organisms and add organic matter below ground. They also leave behind channels through which air, water, worms, and future roots can travel.
Every root left in place contributes to the structure and biology of the soil that supports the next crop.
This is particularly useful when rebuilding compacted soil.
If a plant suffered from a serious soil-borne disease, remove it instead. Otherwise, let those roots become part of the next generation of soil.
For difficult clay soils, you can also plant clay-busting plants that fight compaction and allow their roots to do some of the work for you.
4. Keep something growing
Living roots provide soil organisms with a steady source of food and help maintain biological relationships throughout the year.
Whenever conditions allow, avoid leaving garden soil bare and fallow for long periods.
Perennials are especially valuable because their permanent roots establish long-term relationships with soil organisms. Cover crops can play a similar role in annual garden beds between crops or during the off-season.
Living mulches and ground covers can also keep photosynthesis happening while protecting the soil surface.
This is one reason I value a perennial backbone in the garden. Fruit trees, berry bushes, perennial vegetables, herbs, and ground covers keep roots in place year after year. Annual vegetables can grow among them in the brighter openings and edges.
The result is something closer to a permanent ecology rather than a garden that gets completely reset every season.
Living roots support water stewardship, too. Root systems create channels that allow rainfall to infiltrate the soil rather than running across the surface.
Wild strawberry (Fragaria virginiana) grows as a living mulch or ground cover and yields sweet treats.
Would you like to learn more about improving the quality of your soil? Check out my award-winning book, The Suburban Micro-Farm.
5. Keep the soil covered
Mulch protects the living soil system by reducing erosion, slowing evaporation, moderating temperatures, and sheltering soil organisms.
But mulch is not one-size-fits-all.
A light layer of compost may be useful in vegetable beds where you want the soil to warm in spring. Leaves work beautifully around many perennial plants and shrubs. Wood chips can be useful in pathways and perennial areas. Living ground covers offer the additional benefit of actively feeding the soil through their roots.
Pay attention to moisture as you choose a mulch. Thick organic mulch can be invaluable during hot, dry weather, but too much mulch can hold excess moisture in soil that already drains poorly.
The question is not simply whether to mulch, but what will bring soil, air, and water into better balance in that particular space.
Here are five types of mulch to consider.
When living soil needs extra support
The five practices above do most of the heavy lifting, but damaged or struggling soil can benefit from additional support.
Compacted, disturbed, or newly created garden beds can take time to rebuild. In those situations, certain soil amendments and microbial supports may help improve structure, add organic matter, or encourage biological activity while the larger soil ecology develops.
Biochar adds porous, carbon-rich structure that can provide habitat for microorganisms. I prefer using it alongside biologically active materials such as compost rather than on its own. Here is the biochar I use in my garden.
Edible flowers living mulch: If you’re struggling to figure out how to combine a living mulch with your favorite crops, the answer is this edible flowers seed mix from Botanical Interests. It includes some of my favorite flowers for the vegetable garden including calendula and borage.
Leaf mold adds organic matter and is particularly useful for improving moisture retention and supporting a fungal soil ecology. I compost leaves separately from food scraps and yard waste, and use this rich amendment like compost.
Microbial inoculants, including mycorrhizal fungi, may be useful in newly planted or recently disturbed areas. I use this at planting time, when new roots need help making connections. Here is the mycorrhizal powder and the liquid inoculant that I use most frequently.
Worm castings are a biologically rich amendment that can supplement compost. I especially like them in new beds, containers, and planting holes. I make my own but I also buy bags of castings.
When possible, favor inputs that help build biology, structure, and organic matter rather than those designed simply to produce quick growth.
How to know if your soil is improving
Improving soil should become easier to recognize in its structure, moisture behavior, biological activity, and plant performance.
Over time, healthy soil usually becomes darker, softer, and more crumbly. Water soaks in rather than running off or pooling on the surface. The soil stays moist longer without remaining waterlogged.
You may notice more earthworms, less surface crusting, deeper roots, and plants that recover more easily after heat or dry weather.
Perhaps most noticeably, the garden begins to require a little less intervention.
That is the quiet gift of building soil ecology.
We don’t have to manage every microscopic interaction taking place beneath our feet. Our role is to create the conditions in which those relationships can develop: add organic matter, protect the soil, keep roots growing, reduce disturbance, and allow time for a permanent ecology to take shape.
What is one way you could support the life in your soil this season?
Read Next:
- 5 Types of Mulch for the Permaculture Garden
- How to Get Started with No-Till Gardening
- Why Monocultures Fail: 5 Ways to Build a More Resilient Garden
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