My paper reexamines journal writing, especially in the nineteenth century, as a form that engages with the intellectual and environmental commons. Similar to the archipelagic formation of discrete islands, journals are not solipsistic or purely individualistic. Rather, they enable writers to engage with the stream of conversation happening around them, situating the writer in a relational position to the intellectual material published in periodicals and other “authorized” forms. In particular, I emphasize Henry David Thoreau’s Journal (especially the manuscript fragments housed at The Huntington Library) to show how Thoreau uses the journal form to engage with environmental theories circulating in the nineteenth century. By emphasizing the role of poetry in studying nature, Thoreau strives to translate scientific observation into literary form. While scholars like Kristen Case have compellingly illustrated Thoreau’s scientific Kalendar project and his later study on forest succession, I suggest that the seeds of these projects began in earlier metaphors and sketches throughout the Journal. Reading the entries as forms of “veer ecology”—drawing on Jeffrey Jerome Cohen and Lowell Duckert’s edited collection of that name —I argue that Thoreau uses the short, aphoristic style of the journal entry to explore environmental themes. Focusing on plant growth and building on pea root research by Monica Gagliano, I claim that Thoreau’s language and penchant toward illustrations embodies a type of “radicle” empiricism—the radicle being a plant’s taproot—where the contents of the Journal progresses like roots exploring their world underground. Therefore, Thoreau’s Journal not only anticipates recent plant science, which shows how roots are able to sense and explore the world around them, but it also suggests a way forward in our current ecological moment: to explore the intellectual, artistic, and environmental commons through personal, experimental, and creative “radicle” journalistic inquiry.