Urban Agriculture can it save the planet?
Homegrown Tomatoes – Climate Friend or Foe?
As the days lengthen and warmer weather returns, thoughts turn to gardening for many. Growing your own food offers a satisfying connection to nature and seems like a great way to reduce your environmental impact. But with specific crops, how impactful is that choice?
Paula Owen has been tending a plot in the Isle of Dogs allotments in London for a decade. The community's history is evident in its resourcefulness - repurposed wartime shelters serve as sheds, raised beds are crafted from old scaffolding, and hazel sticks offer sturdy support for climbing plants. The stark contrast with the nearby Canary Wharf financial district highlights the potential for green spaces within bustling cityscapes. Owen feels a sense of pride in the area's low-impact ethos, noting the nearby city farm with its resident animals.
For Owen, and countless other gardeners, their plots represent a sustainable way to contribute to their communities, offering fresh produce without the environmental cost of packaging and transportation. So, a recent study published in January 2024 came as quite a shock. The research indicated that urban agriculture in Europe and the US actually has a carbon footprint six times greater than traditional commercial farming.
Focusing specifically
Focusing specifically on collective gardening spaces like community gardens and allotments, the study placed these at the highest end for carbon emissions (0.81kg CO2e per serving). Surprisingly, this outweighed both conventional agriculture (0.07kg CO2e) and individual backyard gardens (0.34kg CO2e). Owen found this hard to reconcile with her initial views. "It feels a bit unfair," she comments, "like the big guys are going after the little guys."
This sentiment was widely echoed across social media, with gardeners expressing dismay and disbelief that their cherished hobby might potentially be harming the environment. Jason Hawes, lead author of the study and a PhD candidate at the University of Michigan, acknowledges the range of feedback he's received. While some reactions were less than enthusiastic, many gardeners expressed a sincere desire to learn how they could further reduce their carbon footprint.
Hawes himself grows vegetables at his home in Tennessee and is quick to dispel any claims that the study received funding from commercial agriculture interests. He states firmly, "That is absolutely not true." Funding sources are openly listed in the study and include public institutions from countries like the US and the UK. Moreover, he underscores the importance of urban agriculture and that the study's authors strongly believe in its value.
The Nuances of Growing Your Own
Owen recognizes that many people approach gardening with little to no prior experience. For these eager beginners, she enthusiastically recommends tomatoes as a fantastic starting point. The satisfaction of harvesting your own sun-ripened tomatoes and transforming them into a delicious homemade sauce is truly unbeatable. Likewise, lead researcher Jason Hawes notes that one of the primary motivations for participants in the study, beyond reducing their environmental impact, was the sheer enjoyment and fulfillment of growing their own food. It's a rewarding hobby. Unfortunately, this enthusiasm sometimes leads to overproduction and a portion of the harvest going to waste.
Sally Nex, author of "How to Garden the Low-Carbon Way," believes many people vastly underestimate the ease of composting food scraps. "Even with just a small balcony, it can be done," she insists. She sees urban gardens as essential components of a "circular food system" where nutrients are continuously repurposed, reinforcing the connection between what we eat and how we dispose of waste. While acknowledging the issue of occasional overproduction, especially when focusing on a single crop, she points out that gardeners often find ways to share abundance. Jams, preserves, and participation in local farmers' markets are all solutions. She cites a community garden in the coastal city of Brighton, England, which provides fresh produce through a Community Supported Agriculture (CSA) program, offering a direct link to the community and supporting the garden's operations.
Image Credit - Freepik
Beyond the Data
Hawes and his fellow researchers are keen to expand their studies into other regions of the world. Importantly, they hope to delve deeper into the social and behavioral aspects of urban agriculture, a crucial element missing from the initial data. However, one thing they don't want is to stir up unnecessary controversy. The benefits of urban agriculture, especially smaller-scale efforts, are undeniable. It fosters community connections, promotes local food systems, and encourages environmentally-conscious choices; all valuable in the fight against climate change.
Nex agrees that the advantages extend far beyond the simple act of growing food. She emphasizes the physical and mental health benefits that come with gardening. There's also the vital educational component, particularly for children. "A garden teaches you the true origins of your food," she asserts.
The Isle of Dogs gardeners share this viewpoint and actively work to instill it in the next generation. They frequently host gardening workshops for the neighboring school. "There's such potential for impact," Owen says. "It's about educating those who come after us."
The Hidden Costs of Commercial Farming
To fully understand the results of the urban agriculture study, it's vital to understand the parameters used to assess conventional agriculture. The researchers relied on extensive academic literature to pinpoint carbon footprints for the five most commonly consumed fruits and vegetables across multiple countries. This included factors like fertilizer usage and the percentage of these crops imported rather than grown domestically. For the urban agriculture side of the equation, gardeners at 73 small sites in countries like the UK, US, Germany, and Poland meticulously logged their methods and any infrastructure used (like raised beds). Notably, the study did not include energy-intensive vertical farms.
The outcome for conventional agriculture was surprisingly consistent – a remarkably low carbon footprint of around 0.07 kg of CO2e per serving. Hawes acknowledges that this might seem counterintuitive, but points to the powerful economic pressures that force efficiency within the industry. However, he does accept the argument that comparing the urban dataset to a much larger sample of commercial data is problematic from a statistical perspective. Note that the 250 figure cited for conventional agriculture likely refers to life cycle assessments, some of which may encompass multiple farms.
It's also critical to contextualize this within the broader picture. Globally, commercial crop production for human consumption accounts for approximately 5% of all greenhouse gas emissions. Urban growers obviously contribute a minuscule fraction of this, though they would also produce less food overall. Hawes confirms his study did not measure the carbon cost of consumers driving to purchase produce or any retail packaging involved, though generic supermarket emissions were factored in.
The Power of Choice
The study highlights that a handful of highly sustainable urban farms achieved the lowest carbon emissions of all. This suggests that gardeners can significantly lessen their impact by focusing on resourceful practices: recycling materials, extending the lifespan of tools, and avoiding synthetic fertilizers. Choosing to grow crops like tomatoes and asparagus, which often travel long distances or are produced in energy-intensive greenhouses, empowers home growers to have a greater positive effect.
Yet, Sally Nex expresses frustration with how the study's results were initially reported. "The problem is the headline most audiences take away," she says. "It discourages people from making a positive change." She highlights that the new generation of gardeners is increasingly attuned to environmental concerns and demonstrates a strong commitment to practices like reusing materials, creating their own natural fertilizers from plants like nettles and comfrey, and utilizing "no-dig" methods to preserve soil carbon content. Compost and wood chip mulching further serve this purpose.
A Green Revolution
Nex sees a seismic shift underway in the world of gardening. The outdated model relying heavily on peat-based products, pesticides, and plastics is gradually being abandoned. She advocates for gardeners to actively save their own seeds to lessen reliance on external resources and encourages them to pressure their local garden centers to discontinue selling peat-based compost. Extracting peat from carbon-rich peatlands carries a severe environmental cost. While the UK government has promised to ban peat compost sales by the end of 2024, Nex stresses the need for swift legislative action and highlights the delay in bans on other peat products to 2030.
Cultivating Change, One Garden at a Time
While the carbon footprint conversation is important, Owen from the Isle of Dogs allotments stresses the need for a broader perspective. Community gardens offer much more than just locally grown produce. "People gather, share tea and cake," she says, highlighting the social element they provide. She mentions how one plot is maintained by a school for their students, and another serves as a therapeutic space for local patients, demonstrating the value of green spaces for mental well-being.
These benefits align with a 2024 study examining 39 community gardens across Munich and Berlin, which found them to be important havens for threatened plant species and pollinators like wild bees. While Hawes' research paper acknowledges some social benefits, he admits it overlooks elements like food sovereignty – the concept of people having greater control over their own food supply. The study wasn't designed to be a condemnation of urban agriculture; instead, it serves as a reminder, says Hawes, that "like any system, urban agriculture must be designed and implemented with efficiency and sustainability in mind."
Despite some concerns raised about the methodology, Owen admits the research made her contemplate her own allotment's practices. She already utilizes locally sourced materials for structures, saves her own seeds, and carefully maintains her tools for longevity. Clever techniques like growing vertically allow her to maximize yields within a limited space. She avoids the supermarket produce aisle. Instead, whenever she craves apples, she knows exactly where to go – her own garage, where dozens of her own homegrown apples are stored.
The Power of Community Action
Sharing knowledge is another powerful tool in the move towards greater sustainability. Owen suggests tomatoes as a fantastic starting point for novice gardeners and emphasizes the joy of making your own sauces. Hawes notes that this kind of enthusiasm, coupled with a sense of environmental responsibility, was a common theme among participants in their study. Unfortunately, for some, this enthusiasm leads to overproduction and potential waste.
Sally Nex believes composting is a vital yet undervalued skill: "Even tiny balconies can accommodate it." This helps close the loop and reinforces the connection between food and waste disposal. She adds that many gardeners share, preserve, or even sell their surplus through local markets or Community Supported Agriculture (CSA) schemes. These CSAs offer a direct link between consumers and their food, providing vital financial support for local growers.
The Future of Urban Agriculture
Hawes hopes to expand his research globally, with a greater emphasis on the social and behavioral aspects often overlooked in purely data-driven studies. But one thing is certain: the overall value of urban agriculture should never be underestimated. The social benefits, the creation of local food systems, and the shift towards conscious consumerism directly support climate action.
Nex underscores the positive impact on physical and mental health and the unique educational role gardens play for children. And in places like the Isle of Dogs, the next generation is already learning from these spaces – workshops with local schoolchildren foster those connections early on. "There's so much we can do," says Owen, "It's the future generation that matters."
Image Credit - Freepik
Sowing the Seeds of Sustainability
While the initial study raised insightful questions, a major factor not considered was the potential for urban gardeners to change their practices over time. Many start without extensive gardening knowledge, but with a desire to learn. As experience and awareness grow, so too does the focus on sustainability. Gardeners talk, knowledge is shared, and resources like Nex's book "How to Garden the Low-Carbon Way" provide practical guidance. Choosing resource-efficient crops, exploring alternative fertilizers, and rethinking materials used for infrastructure all contribute to further reducing their environmental footprint.
Moreover, the concept of "food miles" needs to be carefully scrutinized within the context of urban agriculture. While a tomato grown in Spain and shipped to your local UK supermarket certainly travels a greater distance than one grown in your own garden, the carbon calculus isn't always that simple. Factors like large-scale refrigeration, packaging, and the potential for food waste at retail stores complicate the picture. Growing at home might still hold an overall advantage, but a more nuanced approach than simply measuring distance is needed.
Hawes and his team are eager to address some of these finer points in their future work. Expanding their study's geographical scope and adding social dimensions will offer a more holistic understanding of urban agriculture's true impact and potential. And although their research wasn't industry-funded, they acknowledge the need to actively address the perception of bias due to the study's surprising results.
The Path to a Greener Future
Ultimately, both advocates and researchers agree that urban agriculture, especially the kind practiced at allotment plots or in backyard gardens, is a valuable movement with myriad benefits. The study highlights opportunities for gardeners to further minimize their carbon footprint, and it serves as a reminder that even small-scale actions contribute to climate solutions. For cities striving for greater resilience, urban agriculture offers the potential to increase local food production, reduce reliance on long supply chains, and educate residents about where their food comes from.
There's no single solution to the complex environmental challenges we face, but the power of individual action shouldn't be dismissed. Whether it's composting scraps, saving seeds, or replacing a store-bought tomato with one ripened in your own garden, every climate-conscious choice matters. And as Paula Owen reminds us, it's about more than just the act of growing: these urban green spaces offer community, a sense of ownership over our food, and a vital opportunity to inspire the next generation of environmental stewards.
What Can You Do?
Start small, if needed: Choose one or two easy-to-grow vegetables like tomatoes or beans
Compost food scraps: It can be done at home or sometimes through community programs.
Save seeds: Reduce your reliance on buying new seeds each season.
Support your local urban farms and community gardens: Participate in CSA programs or shop at their stands.
