Even gardens have a carbon footprint. Here's how to reduce the climate impact of urban farming

Urban gardening might seem fairly innocuous when it comes to its overall carbon footprint, but when compared to conventional agriculture, a study released earlier this year would suggest otherwise. 

The study, published in January in the science journal Nature, found the carbon footprint of food from urban agriculture is six times greater than conventional agriculture.

But there are ways that gardeners can reduce their impact. Let's take a look at what's at play.

The study employed citizen science at 73 urban agriculture sites (think co-operative or collective gardens, not necessarily your backyard garden) across Europe and the United States. 

It compared food from large-scale conventional agricultural farms and urban agriculture sites, including professionally managed urban farms, individual gardens and collective gardens.

"The primary contributor to the carbon footprint on our sites that we studied was actually the infrastructure that was invested in growing food," said Jason Hawes, a PhD candidate in the University of Michigan School for Environment and Sustainability and lead author on the paper. 

While some studies have previously looked at high-tech gardens such as vertical farms, researchers looked at low-tech urban farms.

Hawes said there's an embedded carbon footprint in the materials used in your home garden — things like raised flower beds, trellises and tools.

Watch | The carbon footprint of your garden could be higher than you think:

"It's really important to try to find reused or reclaimed materials to invest in the garden because that becomes a really important part of the carbon footprint," said Hawes. 

"Whatever you put in at the very beginning often has a really long-term impact." 

But Hawes says if you already have equipment on hand, don't throw it out.

"If it's already there, keep using it because you're just going to keep producing more food and more social goods with those materials." 

Some collective gardens in Alberta are already taking measures to reduce their impact on the environment.