Kids are our planted seeds. For nine months a mom and dad wait for an embryo to grow into a person; for the next year or so they wait for the child to speak and walk; then they wait for the child to master the skills necessary to begin a program of formal education that might last up through graduate school; during the years of adolescence they simply "wait out" the youngster; and then they wait for the young adult to get up and running economically, so they can recall the credit card. 

Then in time, the planted seed that became the buried seed becomes the fruitful seed; it bears much fruit. The child becomes a contributing adult; the visionary idea becomes a full-fledged program; the trainee becomes trained; the tune becomes a symphony. And so the process goes.

This is the kingdom of God. Jesus sees himself as the planted and buried seed that will eventually bear much fruit.