“That afternoon I was struck by how much more gratifying gardening was than writing.” — Laurie Lisle, Four Tenths of an Acre
There are lots of reasons why this should be so, some quite obvious and others quite subtle. Gardening is an external, largely physical activity; writing is an internal, largely cerebral activity. One might be tempted to say that gardening is more satisfying because it yields more immediately visible results, yet writing very visibly transforms the blank page, filling it with form and content and meaning. Comparing the two is, in some sense, comparing apples to oranges; the alignment of their similarities and dissimilarities is too complex and nuanced to permit a straightforward analysis.
Maybe the answer lies not in the relative merits of these exercises but in their place on the evolutionary timeline of human behavior. Using the broader meaning of the terms, gardening clearly developed much earlier than writing and was practiced more widely throughout a greater portion of human history. It makes sense that the activities of gardening might be connected to more ancient areas of our brain, areas that are tied more closely to primitive motives of survival and pleasure than the language processing regions of the brain, which are relative newcomers on the developmental scene.
I suppose the real wonder is that any of us find the will to leave off gardening for anything other than eating or making love.