Destroying instantiated game objects from prefab when coliding with the ground

Hi, im working on a game where you need to dodge asteroids that fall from the sky. I made a random spawner script with empty game object. from a youtube tutorial. Now I dont know how to destroy asteroids when they collide with the ground. Im new at making games. I tried many diferent options.Puting destroyer scripts i found online in the spawner script, didnt work. making a new script and adding it to my asteroid prefab, didnt work. I dont know what to do. im using this script as a destroying script :

 using UnityEngine;
 using System.Collections;
 
 public class Destroyer : MonoBehaviour
 {
     void OnCollisionEnter(Collision other)
     {
         Destroy(this.gameObject);
     }
 }

If anyone can help me i would be very grateful!