What does Florence mean by the word "Seedfolks"? Why do you think Fleischman chose this title for the book?

Florence tells the story of how her great-grandparents walked all the way from Louisana to Colorado in 1859. They were both freed slaves who settled alongside the Gunnison River. She comments that her ancestors became the first black family in the entire county. Her father called them "seedfolks" because they were the first black family to settle in that location. Florence then calls the community gardeners on Gibb Street "seedfolks" because they were the first to plant their seeds in the run-down lot.
Throughout the novel, Paul Fleischman tells stories about various people who immigrated to Cleveland and began planting their seeds in the garden on Gibb Street. Many of the characters throughout the novel were the first members of their families to immigrate to America, similar to how Florence's family was the first to inhabit that particular area of Colorado. Seedfolks are people in their families to move from their ancestral home and start their lives in a new place. Each character who was the first in their family to immigrate to the community in Cleveland would be considered a "seedfolk," which is why he chose that title of the novel.