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Lorraine Johnson thinks of soil as an underground universe comprising tens of thousands of creatures that are our friends.Mark Blinch

Whatever you do, don't say "dirt" when referring to the soil around someone who composts. Avid gardeners, who don't only fuss over their plants but work to build the best soil to grow them in, would never make that mistake.

They're more likely to be figuring out how to enrich the organic matter by drying out vegetable peelings all winter long to work into the earth come spring (a friend of mine does this). Or pulverize chicken bones with a hammer in the garage (my uncle swears by this) to fertilize the soil – if anyone excavated his yard, they might think it's a mass grave dug by a raccoon. Then, there are the eggshell crushers, the coffee-ground or tea-leaf sprinklers, the compulsive mulchers and others who swear that the water in which they soak their beans before cooking (my technique) is the key to providing plants with the right nutrients to help them grow best.

But soil is not only of importance to gardeners. Our food system depends on the stuff – it helps to produce 95 per cent of the food we eat. Soil also is the foundation for the forests that make the oxygen we breathe. It helps store and filter water and keeps carbon dioxide, a greenhouse gas, out of the atmosphere. This year, the United Nations has declared 2015 to be the International Year of Soils to ask us to pay attention to this part of the planet that is under serious threat. As the growing season begins, whether you tend to a patch of earth or a window box, you too can answer the UN's clarion call.

It's an urgent mission, says Dr. Martin Entz, an agronomist at the University of Manitoba, because we're losing soil at about twice the rate it takes for new soil to form. Intensive farming has depleted it, and we build our cities on what is often the most fertile land. Then, there's desertification, erosion and the fact that the nutrients in our food depend on soil quality. If the soil is depleted, so too is our food.

"There is an unrecognized urgency to restore soils so it can continue to produce," Entz says. "I don't think it is a stretch to say that our survival depends on a better recognition of the soil in our lives."

Michael Levenston, of Vancouver's City Farmer, the go-to urban agriculture non-profit that runs a compost demonstration garden and teaches gardening skills, believes this recognition can be gained by working in the garden, and composting. "Making soil, that's really transformative," he says.

It's pretty easy, too. Even if your city collects food scraps you can still save some of the green waste to compost. Put aside material such as vegetable and fruit peelings and coffee grounds and then layer with carbon in the form of leaves or straw. Levenston says there are different backyard compost bins that are animal-proof – even bear-proof – to choose from. If you don't have a garden, you can keep an indoor vermicompost bin where red wiggler worms can turn your old fruit and veg into compost to use to grow plants in containers.

By composting, you are returning nutrients to the soil and building organic matter. "If you have healthy soil, you have healthy plants. It all comes down to the nutrients of the soil," Levenston says.

However, if you want truly healthy soil, there's even more to think about.

In only one gram of soil, says Dr. Fran Walley, a soil scientist at the University of Saskatchewan, you can find 30,000 to 50,000 different species – not tens of thousands of individuals but entire species, such as bacteria, fungi, nematodes and insects all living together in an ecosystem of their own. "All of these organisms are part of a food web," she says. They eat each other, they cycle nutrients in the soil and they turn our carrot peelings into compost.

"The main thing to do is remember that soil is alive," says Lorraine Johnson, author most recently of City Farmer as well as other books on plants, gardening and composting. "It needs tending and to be cared for as a living thing." That means no synthetic pesticides – ever. Remember most of those tens of thousands of species living in the earth are your friends. We don't kill our friends.

Then the real shocker: "Forget the digging," Johnson says. "Don't walk in the planting beds." Especially in the spring. Soil has a structure. It's an underground universe made of things like silt, clay, sand and organic matter. If you were to look inside from the perspective of a tiny creature, you'd find soil pores, old root channels and little pools of water where bacteria are living out their lives. When you dig and step on the soil, you collapse their homes and roadways.

Also, don't rake those leaves, says Johnson. They might look messy, but fallen leaves play an important role in soil health. Not only do they protect the earth from temperature extremes and erosion, they feed living things below. Besides, she says the creatures will incorporate the leafy matter into the soil by June. (Bonus, you can strike raking the garden from your fall to-do list.)

If you remember that soil is more than dirt, you're bound to see the Earth in a whole new way.

Sarah Elton is the bestselling author of Consumed: Food for a Finite Planet.