Translation
He who keeps watch on the wind will not sow,
Go to footnote numberand he who considers the clouds will not reap.
Paraphrase
The one who is concerned about the least amount of wind will never sow his fields because the wind will scatter the seeds more than he desires, and the one who is concerned about any possibility of rain or drizzle will never get his grains harvested because it might rain at just the wrong time. The one who has an aversion to all risks will never do anything.
Footnotes
1
In ancient times they planted their crops by preparing the soil then scattering seed over it by hand, and then using a rake or hoe to pull dirt over the seeds. The person in this example would be concerned that the wind would cause the scattering of the seed to be uneven so that the crop would not have an even distribution.