The secret to healthy soil

There is an old saying that you should plant a $1 plant in a $10 hole. It suggests that you should buy a small plant and focus on improving the soil, rather than waste money buying a large established plant. Time and time again, I have proved this to be true, usually by doing exactly what I shouldn’t. Many of us are impatient, myself included, and want to buy a big plant, thinking that it will look better or fill the gap more quickly, yet if we haven’t made the effort to improve the soil, it won’t thrive or take off as well as a smaller specimen planted into soil that has been improved. When it comes to the vegie garden, you could almost say that you should plant a $1 plant in a $100 hole as most vegies like spectacular soil.

I have learned that healthy soil grows healthy plants – and these plants are less vulnerable to pest and disease problems. Healthy plants also produce great harvests, and the quality and size of your crop is in direct proportion to the quality of your soil. However, creating healthy soil is an ongoing process and with most Australian soils – which are low in organic matter – it helps to add compost every time you plant, at least for the first 10 years or so.

One of the first things you must do to fall in love with your soil is to realise that it is brimming with life, whether we can see it or not. A least one-quarter of the world’s biodiversity lives underground. Earthworms are one obvious indicator of this life, and gardeners love to see worms in our gardens. They are an indication of healthy soil and the potential to create a great garden, whereas a lack of worms can indicate poor soil. Just as important, if not more important, are the tiny creatures that can’t be seen with the naked eye. In one teaspoon of healthy, organically enriched soil there are as many units of life as there are people on the planet. These life forms include bacteria and mycorrhizal fungi, and much more. What do these creatures do? Some of the beneficial soil bacteria help to sequester atmospheric carbon dioxide, which, in our current world state, is very profound. Others break down soil-borne pathogens and pollutants.

Among their many important functions, mycorrhizal fungi extend the root system of our plants via a clever ‘surrogate’ root system, hyphae, which give them greater access to moisture and nutrients. In fact, plants give 60 per cent of the sugars they create to feed this mycorrhizal network.

So, what can we do to make sure we have got lots of worms and microbes in our soil? The main way to improve soil is to add organic matter. This is basically anything that was once living and includes compost and aged animal manures. Sure, if you have heavy clay soil you are going to need to incorporate some gypsum and, conversely, sandy, non-wetting soils might benefit from the addition of a clay such as bentonite, but organic matter is the key. As well as feeding the life in your soil, organic matter has a profound effect on the soil’s water-holding capacity – it basically turns your soil into a sponge. Each 1 per cent increase in organic matter increases the water-holding capacity of your soil by up to 1.5 buckets of water per square metre.

It is also important to think about what you put on your soil – is it going to feed the soil life or kill it? Insecticides, herbicides, fungicides, synthetic, chemical-based fertilisers and soil additives such as most soil-wetters are harmful to the soil flora, while organic additives such as compost, animal manures, organic fertilisers and plant tonics encourage and feed the soil life.

A number of years ago I grew what was Australia’s longest tromboncino at the time, coming in at 1.68m long … that’s a zucchini that is Costa Georgiadis’ height, or so he tells me. It might sound like I’m skiting, and I am, but what I’m really skiting about is the soil. My plant didn’t produce just one long fruit, it produced a number of other fruit that were close to 1m. So, what was my secret? Well, in the 10 years leading up to this I had been adding organic matter to the bed in the form of compost, loads of chook poo and straw, and organic fertiliser, as if it was a sourdough starter that I kept feeding. The soil looked like rich, dark chocolate cake; it was spongy and it smelt sweet and earthy. I created the right environment and this climber was able to thrive.

So, when it comes to vegie gardening, fall in love with your soil, keep feeding it, keep improving it and the rewards will come! Read more about improving your soil here.

Header image by Luke Simon