It is amazing that what Zen philosophy says in one way, the spiritual way, this african proverb says in material sense-more practical to understand Zen.
Zen people says that just sit silently, doing nothing, season comes and the grass grows itself green!
What worked well in a situation, shallow water, same may not work again if situations are changed, deep water.
Sometimes just leaving things for right time to come to do a job is good decision.
In extreme summer one can measure it using same technique!
Spiritual meaning: in material life much is easily achieved as everyone is living same life.
In spiritual journey a little growth happens when the time is right but it turns out to be quantum leap – like measuring depth of deep water with foot- just you need to keep practicing till then.