From the excerpt given, the narrator says that she gave someone a packet of tomato seeds and asks her to plant it for her and that when the first tomato ripened, she would be missed. This gives the impression that she would be gone for a long time.
A tomato takes an average of fifty days to grow and start producing fruits, so saying that when the first tomato ripened that he would be missed shows that she would be gone for a long time.
