In the beginning of the movie, the Peanuts gang listens to a presentation about trees and the importance of Arbor Day by the knowledgable Linus. This inspires them to plant a garden in honor of Charlie Brown, who is known for his love of baseball and the maintenance of his baseball diamond.
As they work on the garden, they encounter several challenges, including a disruptive rabbit who eats their plants. They also face opposition from Lucy, who tries to take control of the project and wants to plant more flowers than vegetables.
When Charlie Brown discovers that his baseball diamond has been turned into a garden, he is initially upset and frustrated, as he has a game coming up against Peppermint Patty's team. However, he ultimately decides to make the best of the situation and embrace the garden.
During the baseball game, the odd terrain of the garden causes a number of silly mishaps and injuries, but Charlie Brown is able to use his knowledge of the garden to his advantage. He ultimately leads his team to victory, thanks in large part to his familiarity with the unusual field.
The movie ends with the Peanuts gang taking pride in the success of their gardening project, showcasing the importance of teamwork and the power of nature.