A sensing system contains a vibration device attached to a stem of an agricultural crop for applying vibration to the agricultural crop, at least one sensor attached to the stem of the agricultural crop for sensing vibration of the agricultural crop caused by the vibration applied to the agricultural product from the vibration device to transmit vibration information relate to the vibration of the agricultural crop and a computing device for identifying one local maximum value among a plurality of local maximum values in a frequency spectrum obtained from the vibration information received from the at least one sensor as a resonance frequency of the vibration of the agricultural crop to determine a growth degree of a fruit of the agricultural crop based on the identified resonance frequency.