Provoking Sustainable Thinking with Tomatoes - Foodprint Mapping

What's different about these two tomatoes?


I can tell you that one of these tomatoes is better for the environment than the other. How can that be? These tomatoes look exactly the same, so what's the difference? The difference is in their foodprint.

A foodprint is the result of all the resources it took to get a food from a farm somewhere in the world, to your plate. You may be more familiar with the term, footprint, perhaps you have even tracked your own carbon footprint. A foodprint is the carbon footprint of a food.

Mapping foodprints with your students is a fun way to introduce systems thinking and get students thinking about our food systems through different lenses.


Foodprint mapping can be done as a mini lesson or as a full unit of inquiry depending on the age of students and the curriculum objectives. By the end of the lesson or unit, students will have a better understanding of the amount of natural resources, energy, water, labour, and money that goes into food production. From their inquiry into the different supply chains of tomatoes, they will be able to identify actions they can take as consumers to minimize the environmental impact of a tomato. On a global scale, they will be able to identify changes within the food production systems and supply chains that could lead to more sustainable food production.


A thought provoking question and a prop is a great provocation to start off this lesson. One of these tomatoes was grown more sustainably, than the other. What journey do you think each of these tomatoes took to get to our plates? How is one better for the environment than the other?


In groups, have students brainstorm and list some factors that could contribute to a tomato having a large carbon footprint. Using these factors, ask students to map out the journey or "foodprint" of a tomato to your plate.


Generally during brainstorming group activities, it is best to let students build on each other’s knowledge and see what they are able to produce with only a few teacher prompts. This helps you as a teacher pre-assess their prior knowledge on a topic and get a general sense of how slow or quick you can proceed with the lesson. Remember, there is no right or wrong answer during this stage of mapping and visible thinking. If students are new to the topic of sustainability and carbon footprints and they are really struggling with being able to list factors that may contribute to one tomato being more sustainable than another, you can provide further information such as one tomato came from the grocery store and the other from your garden. Throughout the mapping brainstorming, it also helps to pause and do a gallery walk around the room so students can look at each other’s maps and add to theirs.


If you’re working with younger students that require more prompting and teacher-modeling of brainstorming, you can do this activity with the full class.


Once students have made their initial maps, you can further their learning by watching this video of the journey of a strawberry.


If you’re doing this activity with older students in middle school or high school, you can include some research from the Foodprints.org website to build further understanding of foodprints.


After students have watched the video, have them return to their maps and add any information they may have learned from watching the video. This is also a good time to record questions for further inquiry. Once students have had a chance to reflect on the video and add to their maps, ask them to draw a map for the home-grown tomato. How is this journey shorter? Does this shorter journey make this tomato more sustainable? How is a shorter journey more sustainable?


The Green Foodprint Cards

After students have had some time drawing and redrawing their foodprint maps, you can create a whole class map or move onto the foodprint cards. Using the foodprint cards with the green borders, ask students to create the journey of the store bought tomato.



What does the journey look like if grown at home?


What would the journey look like if bought at a farmer’s market?


There are many different ways to use the foodprint cards to build understanding and provoke further learning and inquiry.


The Blue Cards

Add the blue cards after mapping a journey. The blue cards are used to bring attention to the resources being used at each stage of the journey. Questions to accompany the cards, what type of energy was used at this stage? How many people were involved at this stage? Was water needed at this stage? Were other resources used at this stage? How does our choice of transportation change the journey? How does choice of packaging impact the foodprint? What is the difference between an organic and non-organic tomato?





Extending Student Understanding

Once students have a good understanding of the differences between a homegrown tomato, verses a farmer’s market tomato versus a grocery store tomato, you can further their learning by inquiring into where the tomato plant came from to begin with.


Key questions to consider:

What is the product life cycle of a store bought pack of tomato seeds?

What is the foodprint of the package of seeds?

How does saving our own tomato seeds lower the carbon foodprint?

How sustainable is buying a tomato plant from a local greenhouse or supermarket?

Do imported tomato seeds have the same foodprint as an imported tomato in the grocery store?

Of these different options, which option is best for me as a consumer?


Remember that these questions are more to encourage critical thinking and do not necessarily need to be researched to determine an answer. The goal is to create a generation of thinkers that understand how our systems are interconnected so that they can make better choices and feel empowered to do so. Whether you buy tomato seeds, buy a tomato plant or save seeds yourself, these are all great actions to help one live a more sustainable life and it’s important to understand our options and impacts as consumers. Buying a pack of seeds from your local greenhouse helps support your local economy. Saving seeds yourself from a supermarket tomato plant provides you with free tomatoes. Each has their place. Should a country that grows its own tomatoes also import tomatoes from other countries? Why do we import tomatoes? Should we as consumers be able to purchase fruits and vegetables out of season? There are many areas for further inquiry and to spark debates and philosophical discussions in your classroom if the time allows.

The Circles of Sustainability

Using the Circles of Sustainability graphic organizer, (Environment, Economy, Society) for each of the cards will also help students look at our actions through the different lenses of sustainability.

Take one card and ask the questions, how does this action impact the community? Impact the planet? Impact the local economy? Impact my health and financial health?



Foodprint Mapping and the Sustainable Development Goals


Foodprint mapping and the foodprint cards are great to use when learning about the U.N Sustainable Development Goals.

How does growing a tomato in a school garden positively impact the SDG's? Which goals does it help? What's the impact of a store bought tomato that ends up in a landfill? So many great questions to explore!


There are many different ways to use these cards for learning and to engage your students with systems thinking. Comment below and share ways in which you have or would like to use them to develop the habits of a systems thinker. Together let’s cultivate a community of sustainable thinkers and action takers.


Download the cards