There are a mountain of metaphors out their for education - some are good, some are bad and some are ugly.
The good metaphors for education are those that label learning as being organic and natural. Making a seed or plant metaphorical of learning is good.
The bad metaphors for education are those that label learning as being man-made. Making sports metaphorical of learning is bad.
And the ugly metaphors are those that imply that learning is both conditional and unnatural. Making business or work metaphorical of learning is ugly.
School is like work. Students need to be like a good employee - good students get paid with good grades while bad students risk being fired. These are all ugly metaphors.
School is like sports. Three strikes and you are out, everyday class is a tryout and you better perform or risk getting cut, and you must compete with others if you want to win the game of life - these are all bad metaphors.
School is like a seed. You plant it and nurture it. Provide it with a healthy environment with the conditions necessary for healthy growth and development. You mindfully observe growth while knowing when to measure and when to trust it. You know that growth requires a certain amount of faith and intuitive thinking - you can't dig up the seed too often for precise measurment without killing it. This is a good metaphor.
Not all metaphors were born equal. Some are better than others, and we must be careful which metaphors we subscribe too.