How to keep your soil happy

Happy soil is the dirt plants grow best in. But ask 10 plants what soil they like best and they’ll give you 10 different answers. They won’t actually say, “I prefer dry sandy loam” or “I like an acid bog” — not unless someone has been doing all too interesting genetic engineering. Plants say it with leaves … or no leaves.

If your plant is growing well, it likes its soil. If it dies, it doesn’t. If the leaves turn yellow, they either need more tucker or the plant has root rot and so can’t eat properly. Or it’s autumn or you have a naturally yellow-leafed plant …

In other words, there is no simple answer. Or, rather, there’s one that is very, very simple indeed: most of the plants we buy in garden centres have been selected for “an average garden”, which means one where the gardener thinks soil is just dirt. Most plants will like fertile, moist soil, rich in humus. But read the label, as others have been selected for often-dry pots on patios — usually plants that evolved in deserts — or are plants that don’t like much phosphorous.

No one feeds the bush. Yet, wildflowers and native fruit grow and nutrients are recycled very nicely. There are endless alternative ways to feed your plants and many of them require no work from you once the system has been set up.

Most gardeners and farmers regard fertility as something you buy in bags. Even organic growers often think in terms of equivalents of artificial fertiliser: so many tonnes or bags of hen manure, compost or blood and bone.

No one feeds the bush. Yet, wildflowers and native fruit grow and nutrients are recycled very nicely. There are endless alternative ways to feed your plants and many of them require no work from you once the system has been set up.

Plants can be fed by the animals, fish or birds that live among them, spreading their dung as they feed. They can be fed by “companion plants” whose deep roots forage for nutrients, transferring them to the surface of the soil as their leaves break down. They can be fed through the actions of bacteria that fix nitrogen from the air into the soil. A bush community recycles its nutrients, with things like leaves and dead insects all feeding the soil.

And, yes, plants can also be fed by manufactured fertilisers and the laborious tending of human beings.

For over 100 industrialised years we have been taught that fertility is bought by the packet or smelly truckload. It doesn’t have to be like that. The Earth takes care of its own. Treat it well: learn to live with it instead of exploiting it, and your soil will create its own fertility.

So what is an easy way to work out if you need to fertilise your soil? Listen to it.

Is it hot, or hot and wet, and is everything growing fast — including the mould on your boots? The faster your plants grow, the faster everything else is probably growing — and decomposing. A garden in Cairns needs much more feeding than a garden in Hobart. Don’t complain that your garden needs too much tucker: the faster it grows, the more it can feed you, too.

How much food, grass, weeds or flowers do you take from your garden? The more you take out of a garden, the more you need to put back in. If your soil has been cropped for generations — and either fed grudgingly or not at all, or with artificial fertilisers — it will almost certainly be lacking in many nutrients.

How much do you give back? The more you recycle “wastes” in your garden, the fewer nutrients will be lost. Throw the outside cabbage leaves or rhubarb leaves down as mulch, stick weeds into the compost, give your kitchen scraps to the chooks for manure or compost.

Some plants also take more of a particular element from the soil; for example, corn takes nitrogen, while cabbages take molybdenum. Remember that the part you actually eat is very small though so, unless you sell your produce, most of the elements that went into creating the plant can be given back to the Earth.

Do animals or birds roam around your Garden? As anyone who has cleaned a budgie’s cage knows, birds excrete a lot. If you have shelter for wild birds, for example prickly bushes, tall trees to safely perch on and water to splash in, you’ll attract them. They get at least part of their food supply from outside and will excrete in your garden as they shelter there.

I’d much rather buy birdseed and hen food and carrots for the wombats to be converted into dung than buy artificial fertiliser. It’s better quality, cheaper and much more fun.

Now, the most important question of all: does your garden feel lush and happy or is it growing weakly, even though the weather is warm?

Someone who listens to the Earth — which is anyone who suddenly realises you can sit or stand quite still, listening, watching, feeling the air around you and working out how it all flows together — will soon know if they need to feed their garden.

And then? Head for the garden centre to buy some bags of Chemical Mix Number 108 — or, far better, pretend you can give your garden 20 years of forest litter. But mulch instead: rich pea straw or lucerne. Mulch lavishly, then scatter on an organic fertiliser — perhaps some old hen manure from backyard chooks or even from bags, or one made by decomposing a feral pest like carp from our waterways. Feed your soil whatever you find that you feel will be good, not just for your garden but the world.

Feed a little and often while your garden is growing. And keep listening to it. Listening to the Earth is not just good for your garden but good for you, too.