How The Soil Food Web Determines If Your Garden Will Be A Success

A teaspoon of healthy soil contains millions of beneficial microorganisms

[Guest post by Phil Nauta]

A teaspoon of healthy soil can contain a billion beneficial microorganisms.

I was a gardener for over 10 years before I learned that, and before I discovered organic gardening and the “soil food web.” That’s when I became passionate about gardening.

Today I’d like to share something important with you that could help you drastically improve the health and success of your garden. I’m going to introduce you to the soil food web, to the inhabitants of the soil.

We call it a “web” to show how they’re all connected. All 6 kingdoms of life – bacteria, archaea, fungi, protists, animals and plants – are part of the soil food web, but we’re largely looking at the little guys, the microbes and insects that work so hard for us.

And my focus today is on cooperation.

Why The Soil Food Web Is Awesome

All of these organisms exist in the same space. They work together and they compete. They compete for land and food and water, but they also join together to produce these same things.

None of this is bad – it’s just nature. It’s all good. As gardeners, we are thrilled by this cooperation because it allows us to garden, to grow healthy food and beautiful flowers.

The cooperation between plants and microorganisms is fascinating. The microbes bring food and water to plants in exchange for other food that’s made by the plants. This is the original bartering system. Plants can send well over 50% of the carbohydrates and thousands of other substances they make during photosynthesis into the soil as “exudates” (food) for microbes.

That just blows me away. The microbes give plants the food they need in return, as well as protection from predators.

One of the most interesting examples is of nitrogen-fixing bacteria, many of which live in little homes right on the roots of certain plants, mostly legumes like clover and peas. These bacteria take the nitrogen out of the air and change it into a form the plants can use.

Plants can’t do this, but they can get carbon out of the air – something the bacteria need. Thus begins the trading that allows all other life on earth to exist.

Certain species of microbes colonize the leaf surface, contracted to defend the leaves against predators and pollution. If they aren’t there, the plants won’t be healthy for long.

Many other species set up shop in the rhizosphere, the area right around roots where a lot of trading takes place. Plants send out specific foods to attract the specific microbes they need at any given time.

What The Gardener’s Job Is

So, if you want the healthiest garden possible, your fun job is to first make sure all of these organisms are there, and then make sure they have what they need. To make sure they’re there, you can use:
-Compost, leaf mold and bokashi, all of which supply organic matter, nutrients and of course, insects and microorganisms.
-Compost tea, effective microorganisms and other microbial inoculants that are inexpensive, efficient and can be sprayed onto plants.

As for what these microorganisms need, that’s the same as the above-ground wildlife we hope to attract, and the same as us:
-Water, which means watering the whole soil, not just the plants.
-Food, which means organic matter and balanced nutrition.
-Air, which means balanced soil to ensure there’s enough.
-Shelter, which means compost, mulch and plants.

Pretty exciting, right? Feel free to post your questions/comments below about improving the biological diversity of the soil!

Check out Phil Nauta’s guest post at Native Plants and Wildlife Gardens, How Chemicals Affect Your Soil and What to Use Instead

[Phil Nauta is a SOUL Certified Organic Land Care Professional and author of ‘Building Soils Naturally’ to be released by Acres U.S.A. this spring. He has taught for Gaia College and been a director for The Society For Organic Urban Land Care. He holds a Certificate In Organic Landscape Management from Gaia College, a Certificate In Sustainable Building And Design From Yestermorrow, and a Permaculture Design Certificate. He was an organic landscaper and ran an organic fertilizer business before starting Smiling Gardener to teach others innovative methods for organic gardening, especially in the vegetable garden.]

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  1. says

    Very exciting. Funny how we always knew the health of the soil was important, hence organic gardening/farming. But as scientists study and learn more about the soil creatures and the ecological niches they form we are learning how to tread lightly and even help restore life to soils left almost barren by former use. Very exciting indeed.
    Did you see the Soil biology movies made available by Iowa state? There are 18 of them, very cool.

  2. says

    Great post. I agree, “The cooperation between plants and microorganisms is fascinating.” I like how you define the bartering system, as people forget that plants give something to the bacteria, too. Where I live in the Santa Monica Mtns, we have plants that work with nitrogen-fixing bacteria, Ceanothus or Mountain Lilacs.

  3. says

    Another player in this complex web is the foreign substances that we introduce. Glyphosate herbicides damage the natural mycorrhizae, and our binge of anti-bacterial products damages the natural nitrogen-fixing bacteria when these products get into the water cycle. These chemicals don’t break down immediately after application – they persist in the environment. We need to break our dependence on chemical “quick fixes”.
    Laurie recently posted..Kitchen and Herbal Giveaway winner


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