At the beginning of the poem "Mother to Son," the mother tells her son that her life has been fraught with struggle and difficulty. She says that life for her "ain't been no crystal stair," but rather a staircase with "splinters, / And boards torn up." The juxtaposition of the word crystal, connoting wealth and beauty, with words like splinters and torn, connoting poverty and ugliness, suggests that the mother's life has been impoverished.
The mother tells her son that she has been "a-climbin' on, / And reachin' landin's, / And turnin' corners." The implication here is that the metaphorical staircase representing the mother's journey through life is long and winding. In fact, it seems as if this staircase is unending, which in turn implies that the mother's life has been a continual, relentless, uphill struggle.
In the second half of the poem, the mother describes the darkness of the metaphorical house. She tells her son that sometimes she has had to climb the stairs "in the dark / Where there ain't been no light." These lines suggest that the mother's life has been difficult because she has had to find her own way, without guidance. Darkness also suggests an absence of hope. This poem was first published in 1922, and Langston Hughes often wrote poems about the experiences of African Americans. Thus, we might infer that the darkness that the mother has had to navigate might refer to the racist oppression and persecution that she has likely faced as a Black woman in early-twentieth-century America.