Home grown veggies, as it turns out, are not only healthy for you, but are also healthy for the planet.
If you want to do your bit to combat climate change, you can start by growing some vegetables in your back yard. Better still, practice organic methods to be even more eco-friendly. This will not only provide you with a fresh supply of healthy, organic veggies, but there is proof that home gardens can also help mitigate climate change.
Home-grown Veggies Can Contribute to Climate Change Mitigation
According to a recent study conducted by researchers at the University of California Santa Barbara, converting your lawn into an organic veggie patch can help reduce greenhouse gas emissions (GHGE) and combat climate change. The results of the study, which were published in Landscape and Urban Planning, show that every kilogram of home-grown veggies produced can reduce greenhouse gas emissions by as much as 2 kilograms, as compared to commercially farmed vegetables purchased from your local store.
The research team, led by David Cleveland, a Research Professor of sustainable food and agriculture in the Environmental Studies Program at the University of California, Santa Barbara, and author of the book titled: Balancing on a Planet: The future of food and agriculture, conducted a lifecycle assessment of the two production methods using computer models. As a starting point, the researchers assessed the positive impact of growing vegetables at home, based on the following factors:
- Turning an existing lawn into a veggie patch;
- Using the vegetables produced in the garden to replace some conventionally farmed vegetables purchased from a store;
- Utilizing organic waste generated in the home for compost rather than sending it to the landfill;
- Diverting household gray water for irrigation.
Yield and Composting Methods Affect Emissions
They also looked at how key factors, such as crop yields and the management of household organic waste, affected the outcome. Surprisingly, the study showed that higher crop yields resulted in reduced emissions overall.
“We looked at high and low yields and found that they affected the emissions per kilogram of vegetable,” Cleveland explained. “For every square meter of garden, if you get 10 times the amount of vegetables, then the amount of emissions per vegetable goes down, because you’re dividing more vegetables into the emissions per square meter. Ironically, that makes the contribution of the garden less on a per-vegetable basis. This means for the garden as a whole, higher yield reduces the emissions because fewer vegetables are purchased.”
The manner in which organic waste is managed in the home can either be good or bad in terms of its contribution to climate change. Cleveland notes that in order for composting to be beneficial to climate it needs to be done correctly, maintaining optimal environmental conditions such as moisture, temperature and air circulation. This requires time and attention, and if not maintained properly, the decomposing waste matter can become anaerobic and start emitting nitrous oxide and methane — both potent greenhouse gases that contribute to climate change.
“We found that if household organic waste was exported to landfills that captured methane and burned it to generate electricity, households sending their organic waste to a central facility would reduce greenhouse gas emissions more than composting at home,” Cleveland said. “This study shows that in terms of effect on the climate, small things matter,” he added. “How much attention you pay to the garden matters. How efficiently the vegetables are produced and consumed matters.”
How Local Programs Help with Efficient Composting
If you are going to compost your household organic waste, it is important that you give this the time and attention it requires, Cleveland stresses. The University of California Santa Barbara has a department specifically devoted to creating awareness of the need for efficient composting — the Department of Public Worms (I kid you not) — which feeds campus food waste to earthworms housed in 8 x 4 foot earthworm bins, which in turn convert it into nutrient-rich organic compost.
However, Cleveland believes that it may not always be in the best interests of climate change for homeowners to compost organic waste on-site. In many cases it may be better to have a centralized facility where household organic waste can be sent for composting. To improve overall efficiency, these programs can collect household organic waste and deliver it to a central point for composting, and then deliver compost back to homes who wish to use it in their vegetable gardens.
“It’s important not to get hung up on assumptions that small and local are always better,” Cleveland said. “They may not be. You have to keep your eye on the real goal and not get tripped up by intermediate steps.”
Your Vegetable Garden Can Make a Difference
The University of California Santa Barbara study then assessed the contribution that home vegetable gardens could make to reducing annual greenhouse gas emissions. The baseline study found that home vegetable gardens contributed 7.8% towards California’s overall 2020 greenhouse gas emission (GHGE) reduction target, 3.3% towards the Santa Barbara County 2020 GHGE reduction target, and 0.5% towards the 2050 GHGE reduction target set by the city of Santa Barbara.
“In addition to reducing greenhouse gas emissions, there are other potential environmental, social, psychological and nutritional advantages to growing food yourself, whether in a household, community or school garden,” Cleveland said. “However, the degree to which those benefits are realized can depend on small things. Our hope is that this research helps motivate households, communities and policymakers to support vegetable gardens that can contribute to mitigating climate change.”
This study highlights the potential offered by our individual home vegetable gardens to help meet climate change mitigation targets for cities, counties, and ultimately the nation. Small contributions add up and can have a big impact — both on your health, the health of your family, and ultimately that of the planet.
David A. Cleveland et al. The potential for urban household vegetable gardens to reduce greenhouse gas emissions. Landscape and Urban Planning, September 2016 DOI: 10.1016/j.landurbplan.2016.07.008