Seed Growing Secretly

Mark 4

26And he said, So is the kingdom of God, as if a man should cast seed into the ground;
27And should sleep, and rise night and day, and the seed should spring and grow up, he knoweth not how.
28For the earth bringeth forth fruit of herself; first the blade, then the ear, after that the full corn in the ear.
29But when the fruit is brought forth, immediately he putteth in the sickle, because the harvest is come.