This past year, I started volunteering at a compost garden in my neighborhood. Every Sunday neighbors come and drop their food scraps off at the garden. We compost the scraps into soil which we use for growing vegetables, herbs, and other plants.
Each week, the garden tracks food scrap dropoffs, amount of compost created, heat generated during the composting process and other numbers in a log book. I thought it'd be cool to explore this real world data in Tableau.
^In this graph, we see the daily temperature vs. the number of food scraps dropoffs. We see a pattern of fewer dropoffs during the hot summer months and cold winter months, and more dropoffs during spring and fall. This suggests that more people stop by the garden when the weather is comfortable.
^ In this graph, we see pounds of food scraps collected over time. We clearly see the effect of Covid on the numbers. More food scraps were collected during Covid as the city halted curbside compost pickup at the time. When this service resumed our own numbers dropped. We can also see how our recent partnership with Little Friends Pre-K (collecting their food scraps each week) partially offset the drop.
^In these graphs, we look at some correlations in our data. The chart on the right shows the more obvious: a strong correlation between the number of dropoffs and pounds of scrap collected. This simply means that the more people stop by the garden, the more we collect.
The chart on the left shows a weaker correlation but a more interesting one. As part of the composting process, we pack food scraps into dense piles inside a metal box. Microorganisms break down the food scraps over the next few weeks, generating heat. We can see that the more pounds of food scraps in the pile, the more heat is generated.
Here’s a link to the charts if you’d like to take a closer look:
https://alandavidgrunberg.github.io/Compost_Garden_Analysis/