Question

give the meaning of Plucking the grass to know where sits the wind

Answer 1

Constantly tossing blades of grass into the air to find out which way the wind was blowing

Answer 2

Plucking the grass:

The simple meaning for plucking of the grass is to find the wind direction with grass.

If we pluck a hand full of grass and hold it, due to the less in weight of the grass it tends to move based on the direction of the wind, as the wind has the power to blow the lite weight grass.

So, we can find the direction of the wind blowing.