Even though the series of parables Jesus offers are powerful, impactful messages to be understood, the disciples ask for clarification later in the chapter (vs. 36)
Farmer represents us, and the seed our faith. He says that the kingdom of is like the seed small when planted, but when it grows it is strong and plentiful.
Luke 17:6 "If you have faith as small as a mustard seed you can say to this mulberry tree, "Be uprooted and plant in the sea," and it will obey you."