Just like a sponge cake, a sponge garden needs the right ingredients to make it rise, landscape gardener Mark van Kaathoven says.
He has been using the concept on his own 427sqm property in inner Auckland, and through droughts and floods in recent years his garden has flourished, he told RNZ's Saturday Morning.
Van Kaathoven stopped green waste going to landfill and is instead using it to make a sponge garden.
Photo: Nick Monro
He has only taken four bags of green waste to the tip in last 15 years.
"It's just layers and layers of green waste and other bits and pieces, hedging, lawn, and it's compounded, and then it creates this rich microbiome mixture of compost, and that's where all the major organisms and genetic stuff goes on, which is the foundation for your garden," he said.
Your garden will thank you for mimicking the layering that goes on in nature, he says.
"It's like a recipe - if you don't have the right recipe or right ingredients for a sponge, it won't rise.
"Well, the same thing applies with your garden. You've got to put the right ingredients together for the garden you want to have for the future."
Photo: Nick Monro
His whole garden is a "compost heap", he says.
"That's how the garden grows, that's how Mother Nature grows in the natural wild."
Don't get too hung up on the manicured lawn look, he says.
"A lot of people are kind of stuck on the 1957 Yates Gardening Book Manual, and they want the very sharp-edged trimmings of buxus hedging and lawns, which is fine to some degree, but I think if you balance it with a little bit of natural environment the two balance and out really beautifully."
So spongy is his garden, he has disconnected most of his guttering down pipes, and the property stood up to Cyclone Gabrielle and the Auckland Anniversary floods fine, he says.
"If anyone should have got flooded, it should have been me, because my garden was getting a good dose of water.
"But my neighbours all got flooded, we didn't get flooded here. It's quite remarkable. I mean, I didn't plan it that way, it just evolved that way."
Now he is taking those micro lessons to a bigger scale.
Auckland deputy mayor Desley Simpson is a fan and wants to roll out his "green infrastructure" approach to make the city more resilient, he says.
"She wants to see this in The Domain and in other parks around Auckland. There's 600 parks that I could see this happening everywhere. And again, these parks can all be utilised by people like myself with their green waste, instead of taking it to the tip."
His own small garden, meanwhile, is a haven, he says.
"I've got morepork in my backyard. I've got kererū, I've got tūī, I got fantails, I've got gray warblers, it's gorgeous, and I'm 15 minutes from the Sky Tower.
"If something like this can be done so close to a concrete jungle, there's no excuse why we're not doing it elsewhere."
Photo: Nick Monro
