Question

Which plant gives signal when the soil becomes dry?

Answer 1

When plants start growing the soil crack because it is growth of roots .

All plants can shows crack if they are dried.

Answer 2

Plants like crotons display clear signal about the dryness of soil.  

These plants do not have very deep root and as the result they collect water from the first layer of the soil.

When the soil gets dry these plants can’t suck water from the surrounding layers and tend to get dry.

These plants provide the first signal that the soil has turned dry.