by Liz Marquette, Hood College

Part I: Why Teach Composting?

Department of General Services (n.d.). Organics recycling program.

Food and Agriculture Organization of the United Nations (FAO; 2013). Food waste harms climate, water, land and bio- diversity. item/196220/icode/

Grasserova, A., Hanc, A., Innemanova, P., & Cajthaml, T. (2020). Composting and vermicomposting used to break down and remove pollutants from organic waste: A mini review. European Journal of Environmental Sciences, 10(1), 9–14.

Next Generation Science Standards (n.d.). Read the standards.

Cornell Waste Management Institute (2018). Small scale or backyard composting.

United Nations Convention to Combat Desertification (2022). Drought in numbers.

Waliczek, T., McFarland, A., & Holmes, M. (2016). The Relationship between a Campus Composting Program and Environmental Attitudes, Environmental Locus of Control, Compost Knowledge, and Compost Attitudes of College Students, HortTechnology, 26(5), 592-598.

According to the United Nations Convention to Combat Desertification (2022), soil management is a crucial component in combating the climate crisis.  Providing students with an understanding of the composting process can be the first step in this endeavor. While not without challenges, composting within the school system can increase student interest in the classroom, knowledge of sustainable practices, and understanding of many scientific concepts in alignment with the Next Generation Science Standards (NGSS, n.d.). To this end, a number of schools across the country have begun to take a hands-on, experiential learning approach to the topic.  For example, many school districts within the United States have implemented aeration or red wiggler worm-based composting programs to be used as an educational tool, as well as a waste management tool within their communities. By supporting student learning in the classroom with real-life applications, educators can encourage students to deepen their understanding of the impacts of composting through evidence-based initiatives. First and foremost, however, both students and educators should develop a firm understanding of what composting is, and the integral role it plays in the environment.

According to Waliczek et al. (2016), with the American Society for Horticultural Science, “Food waste is one of the most abundant materials contributing to landfills in the United States” (Waliczek et al., 2016). It is estimated that over 90% of our food waste is returned to landfills (FAO, 2013). This waste generates greenhouse gasses which ultimately interact with global climate change. Specifically, the Food and Agriculture Organization of the United Nations reports that this waste contributes to an additional release of 3.3 billion tons of greenhouse gasses (FAO, 2013). When students are educated about these concepts, studies show that their long-term understanding of composting increases, their scientific disciplinary literacy increases, and their attitudes towards the environment improve as well (Waliczek et al., 2016). These factors alone give reason to include lessons on composting within the classroom.

Part II: What is Composting?

Composting is a part of the natural life cycle of plants and animals. When we talk about composting, however, in society’s vernacular, we are typically referring to the human-facilitated solid waste management of organic materials (Cornell Waste Management Institute, 2009). Typically, people encourage the composting of organic materials by developing a compost pile, or establishing a compost system that uses red wiggler worms to aid in the composting process (Department of General Services, n.d.). In either system, living organisms work to break down the organic material. When people build these piles, they are creating the ideal living environment for microorganisms to thrive to break down the organic waste. Composting occurs when brown materials (dead leaves and decomposing tree trimmings), green materials (fruit and vegetable waste and live yard waste), and water interact, as shown in Figure 1 (Organics Recycling Program, n.d.).

Figure 1

Composting Process Imagery

With the assistance of bacteria and other microorganisms, these materials eventually break down to form the compost, a material that resembles dirt. If worms are used, the worms digest the organic material, and the waste that they produce is used as the compost. While this is a simplified explanation of the process, students could do a much more thorough investigation into the chemical processes that are occurring when materials decompose. For this reason, lessons on composting at home, in the classroom, or in the community can be adapted to meet the needs of almost any learner.

Part III: Advanced Content Curriculum

Although students will be able to reach a practical level of understanding through lessons on composting, in order to best educate regarding this topic, it may be desirable for the educator to dive deeper into the content area. Specifically, the concept of utilizing earthworms to aid in the composting process, otherwise known as vermicomposting, can act as a way to connect student understanding of environmental biology to student background knowledge.  Alternatively, when earthworms are specially utilized to decompose environmental pollutants, this process is known as vermiremediation (Grasserova et al., 2020). Both vermicomposting and vermiremediation are processes that are actively being researched as approachable mitigation techniques that can help decrease the human impact on the climate crisis. With this knowledge, teaching students about these processes could open the door to potential careers researching in the fields of sustainability, environmental biology, and ecology. Without a doubt, the potential to use composting for potential climate harm reduction or community benefit is substantial.