George Washington Carver was always interested in plants. When he was a child, he was known as the "plant doctor." He had a secret garden where he grew all kinds of plants. People would ask him for advice when they had sick plants. Sometimes he'd take their plants to his garden and nurse them back to health.
Later, when he was teaching at Tuskegee Institute, he put his plant skills to good use. Many people in the South had been growing only cotton on their land. Cotton plants use most of the nutrients in the soil. (Nutrients provide nourishment to plants.) So the soil becomes "worn out" after a few years. Eventually, cotton will no longer grow on this land.
This was especially bad for poor African American farmers, who relied on selling cotton to support themselves. Carver was dedicated to helping those farmers, so he came up with a plan.