Food for the Soil

SERIES 25 Episode 04

Jerry shows how to refresh your soil with a range of natural ingredients

"In a productive garden like mine," says Jerry, "I'm constantly picking fruit, leaves and roots. That means I'm removing nutrients and they need to be replaced, so by feeding the soil that feeds the plants, they feed me. Feeding the soil keeps this cropping cycle going."

"One of the best ingredients for doing this is manure - or as my granddad used to call it, dung. Dung doesn't just provide nutrients or just simply improve the quality of the soil. Every single particle arrives with its own ecological community. This is packed with bacteria, fungi and protozoa and they enhance the biological activity of my soil. They keep my garden fertile and flourishing. But manures aren't just manures. The best ones to use in the garden come from herbivores - vegetarian grazing animals like cows and horses. These are very popular manures. It's best to steer away from carnivore manure - things like cats and dogs - which can introduce diseases into gardens."

But manures are only as good as the animals are themselves. Recently, a circus visited Brisbane and Jerry says the animals there were fed like royalty, so he went along to pick up some different dung to experiment with.

He found the buffalo manure rich, wet and heavy. Camels also produce quite a rich mixture. He's also collected llama manure, which is drier and produced in pellets colloquially called 'beans'.

Jerry uses the manure from his guinea pigs - what he and his sister used to call 'guinea bombs'. He says it's a ready-pelletised fertiliser he says is great for pot plants.

"Remember - whatever type of manure you use, try and get whatever is cheap and locally abundant!" he says.

Hot manure

Fresh manure can generate quite a lot of heat as it's broken down by bacteria. Horse manure is called a 'hot manure' because it generates so much heat that it can actually catch fire! Jerry prefers to compost his horse manure rather than use it immediately, as it's often laden with weed seeds. Alternatively, it can be dried out - this stops the bacteria working and causing heat. Fungi take over the decomposition, letting it become cool and easy to use.

Jerry mulched one of his beds with horse manure four months previously. It's now matured into the perfect bed for sowing corn. He first just loosens the soil with a rake, then broadcasts food-grade corn for animals thickly over the bed. He then rakes it into the soil - when it grows, it will provide for his guinea pigs, repeating the nutrient cycle.

Cold manure

The manure from ruminant animals - things like goats, sheep, cows and buffalo - create what's known as 'cold manure'. This is because these animals have complex digestive systems that strip most of the nutrients from their feed, so they produce low-nutrient manure - so bacteria don't have the chance to heat up the dung.

Jerry likes to use these cold manures as soil conditioners, as they retain moisture and add organic matter to the earth. He likes to actually dig these kinds of manures into the top soil, but no deeper than the depth of a spade. If dug in any deeper, the microorganisms that use nitrogen as a source of energy will release methane as a by-product of their metabolic process. This means the available nitrogen from the manure will be lost.*

He sows a bed he's prepared with cold manure with Day gai choy. As these plants have very small, fine seed he just scatters them thinly over the surface and rakes them in very lightly. He then mulches them with some chopped sugar cane - if kept moist, they should be ready to eat in around three weeks.

He's also taken some cuttings from one of his favourite productive root crops - coco yams. The cuttings have been dried out in the shade for a week but are now ready to be planted. Jerry's top-dressed the cuttings with a mixture of llama and camel manure, ensuring there's a variety of nutrients available to these hungry plants.

"Well, it's been a long, hot dry summer here in Brisbane but thanks to lots of fantastic manure, my soil is humming with life, my crops are really well nourished and I'm set for the gardening months ahead," Jerry ends.

* EDITOR'S NOTE (5th May 2014): This fact sheet has been amended for clarity.