FROM THE GROUND UP

A HEALTHY SOIL, TEEMING WITH LIFE, IS THE KEY TO A THRIVING PLOT OF FLOWERS OR VEGETABLES. DIANE MIESSLER EXPLAINS HOW TO IMPROVE YOUR SOIL – AND HOW IT’S A BIT LIKE BUILDING A HOUSE…

Iliken my approach to gardening to living a healthy lifestyle, as opposed to struggling with bursts of dieting and exercise. Instead of spending weekends feverishly weeding, tilling, and fertilising, followed by long stretches of neglect and guilt, I enjoy regular puttering that keeps the garden tidy while feeding the soil.

This approach is much easier than the one I was raised with, which was a carpet-bombingwith-chemicals, nature-as-adversary attitude. It focuses on giving soil what it needs to nourish the plants I want to grow. Gardening with nature as an ally is simply a matter of offering a variety of foods for germs and worms – the plants will attract the microbes they need to flourish, given enough choices. A cubic foot of healthy soil contains trillions of living things. Trillions. Literally. Bacteria, fungi, protozoa, archaea, arachnids and worms, all working together to feed plants. Diseases are kept in check by this vast population of largely beneficial organisms – known as the soil food web – which compete with these diseases or eat them, and produce robust and healthy plants. And I’ve found creating rich soil is a lot like building a house. Well, kind of. If you build

a house from the roof down…

START WITH THE ROOF

Soil needs cover to shelter it from the elements: air, temperature extremes, and too much or too little moisture (flooding, erosion, desiccation). Avoid bare dirt; keep it covered with live and/or dead plants – crops, cover crops, or mulch — to protect the soil food web there.

Mulch does many things for your soil.

First, it shades and softens it, and dramatically decreases the amount of watering required; your soil will be moist and easy to “spot-dig” when it comes time to plant. More importantly, though, mulch can provide everything needed for nature to start doing its magic. Healthy soil is alive soil, and that life needs moisture and organic matter to thrive.

Mulch can be made from lots of things: cardboard, thick sheaves of wet newspaper, straw or hay, leaves and other garden waste, or the plants you just pulled up. The more – and more diverse – your mulch, the better.

After a month or so under a deep layer of organic matter that’s been kept moist, your garden soil will be soft and full of worms. When that happens, you’ve basically turned your entire planting bed into compost.

As the old saying goes, “nature abhors a vacuum.” If you leave soil uncovered, nature is likely to put weeds in it. Another way to avoid this is to plant cover crops, basically living mulch. Sometimes called green manure because they add nitrogen to the soil, cover crops accomplish several things. By sending roots deep into the ground, they break up soil clods into crumbs, insert organic matter, attract soil organisms, and, when they rot, create empty channels for the soil food web to live in. The green plants, once you cut or flatten them and mulch over them, decompose into nitrogenrich compost while feeding soil microbes.

BUILD THE WALLS

Organic matter gives soil structure and forms the building blocks of your ‘house’; as it decomposes, it creates soil particles in different sizes. Members of the soil food web, in the process of feeding on organic matter and each other, add still more variety to the size of particles (think tiny dead bugs). And certain members of the soil food web – worms – create some of the most fertile and best-textured soil around, coming in the form of worm poo, or – to put it more delicately – castings. Aggregates of mineral particles, germs, worm castings, and bits of dead bugs: it’s these crumbs that are what gives good soil its structure.

You don’t need to haul in truckloads of topsoil and compost; the plant waste that is growing in your garden ( prunings, pulled-up weeds) or coming from your kitchen will be enough to feed the soil. Plant a few things at a time, dig in a handful of compost, and mulch. In areas where I’ve been growing things for a few years, my soil becomes soft and rich.

This happens not from any large-scale tilling in of organic matter, but because each time I add seeds or plants, I chop up a little more soil and add a handful of compost. All plant life improves soil by feeding the soil food web. Far from depleting it, the packing of your garden with a variety of plants will only enrich your soil; life attracts life.

Walking on soil compacts it and results in hardpan, a nearly impregnable layer of hard dirt below the soil that you’ve turned and planted. Protect your soil from being trampled by installing paths that give you access to permanent planting beds. These beds should be small enough that you can reach any part of them from a path, without having to walk on the growing area.

VENTILATION AND PLUMBING

Your soil ‘house’ will need a steady supply of fresh air and water. The best way to provide these is by nurturing and protecting the precious soil food web. Biologically active soil turns soil particles into larger crumbs; these allow water to be absorbed and the excess to leave by means of gravity. The resulting vacuum will pull air into the newly empty spaces. Voilà! Plumbing and ventilation!

Living soil is well-aerated soil. Air is brought into soil in many ways, by many life-forms. Earthworms dig holes as they eat organic matter. Mycorrhizae, protozoa, and arthropods aerate soil with their comings and goings. And bacteria knit small soil particles into larger crumbs that make spaces for air.

Our goal is to create a happy world for the soil food web by feeding it (with mulch, compost) and keeping it moist and aerated.

The best thing we can do for the soil food web, and for the planet, is to garden gently. Tilling destroys fragile but vitally important mycorrhizae (fungal strands) and chops up earthworms and other garden friends. Avoid chemical fertilisers that will damage that soil food web by killing indiscriminately. A healthy soil food web will control pests and provide all the food that your plants need.

Once your soil is happy, the good news is that pulling up spent plants and weeds is all the soil loosening you’ll need to do. Those plants leave behind some root filaments (organic matter) in the soil. The place where the roots used to be is now filled with air.

And when you mulch with the plants you’ve pulled up, they form a nourishing home for more worms and germs, which are the best things for your plants.

“Gardening with nature is simply a matter of offering a variety of foods for germs and worms”

Taken from Grow Your Soil!: Harness the Power of the Soil Food Web to Create Your Best Garden Ever by Diane Miessler (Storey Publishing).