Lines 1-5 introduce the poem's central, anthropomorphic character: the "earth" itself. The speaker addresses the earth through apostrophe, using a lofty-sounding "O" (a version of "Oh" often used in older English poetry to invoke gods, muses, abstractions, and other absent or non-human figures).
The speaker describes the earth as "sweet" and "spontaneous," suggesting that this will be an appreciative nature poem. Over the course of the poem's extended metaphor, it becomes clear that the speaker is in fact comparing earth—or nature—to a sweet, spontaneous, beautiful woman.
As the first stanza transitions into the next, it introduces the image of "fingers" behaving in a "doting" (affectionate) fashion:
O sweet spontaneous
earth how often have
the
doting
fingers [...]
Notice how the language unfolds slowly down the page, with short, irregular lines and dramatic enjambments between lines and stanzas. The word "the" is given the weight of its own line—highly unusual, because it's rarely an important word on its own!—as is "doting."
Meanwhile, "fingers" is not only enjambed over into a new line/stanza but also indented, adding extra white space on the page. All these effects make the language seem to dawdle and linger, like "doting // fingers" caressing something or someone. The soft alliteration of "sweet"/"spontaneous" and "how"/"have" makes the lines themselves sound sweet and harmonious. After this pleasant opening, however, the poem is about to take a slightly darker turn.