Bible Verses About Parables: Seed growing secretly

And he said, "The Kingdom of God is like a man who scatters seed on the ground.

Nights he sleeps, days he's awake; and meanwhile the seeds sprout and grow -- how, he doesn't know.

By itself the soil produces a crop -- first the stalk, then the head, and finally the full grain in the head.

But as soon as the crop is ready, the man comes with his sickle, because it's harvest-time."