Symbolism, Imagery, Allegory
As every amateur gardener knows, it takes two things to make a plant grow: sun and rain. (Also, you need to not put your potted plant on top of the radiator. Whoops.)
And because of this sun + rain = plants equation, the symbolism of the sun and the rain have become pretty life-affirming. You have the song "You Are My Sunshine." You have the song "On the Sunny Side of the Street." If someone is acting super chipper, you refer to them as acting "sunny."
So, it's no shocker that in this novel, Janie eventually comes to associate Tea Cake with the sun. He makes her happy. He gives her life—or, at the very least, he makes her life way better. And even after he dies, Janie continues to think of Tea Cake in terms of the sun: although he's deceased, he continues to enrich Janie's life. (Aww.)
Check it out:
Janie buried Tea Cake in Palm Beach…Janie had wired to Orlando for money to put him away. Tea Cake was the son of Evening Sun, and nothing was too good. The Undertaker did a handsome job and Tea Cake slept royally on his white silken couch among the roses she had bought. He looked almost ready to grin. Janie bought him a brand new guitar and put it in his hands. He would be thinking up new songs to play to her when she got there. (19.182)
There's another symbolic layer to this equation of Tea Cake and the sun, too. The sun demonstrates, simply by rising day after day, that life goes on, no matter how tragic yesterday was. For Janie, Tea Cake’s memory will be as enduring as the sun.
Say it with us this time: aww.