Spawned objects not triggering Unity3D

Question

I am making an FPS game. It has pickup-ables (juices/energy) which increases the player's health. Now I'm able to do that with a single cube (just using a cube for testing). The OnTriggerEnter works like a charm, it increases the players health as well as maintains the health bar. But, when I instantiate it, the spawned cubes' triggers don't work.

I've added my "Spawner" and "HealthIncrease" scripts below. Oh yeah, and I have added rigid bodies/box colliders everything.

This is my Spawner Script(I add this to the Empty Game Object)

public class Spawner: MonoBehaviour {

    public GameObject Power;
    public GameObject player;
    public float spawnOffset=3.0f;
    public float spawnDelay = 5;
    int currentPowerUpCount;
    int currentWaveNumber =1;

    Vector3 randomSpawnPoint{
        get{

            int randIndex = UnityEngine.Random.Range(0, transform.childCount-1);
            var position = transform.GetChild(randIndex).position + UnityEngine.Random.insideUnitSphere * spawnOffset;
            position.y =0;
            return position;

        }

    }
    void Start(){
        currentPowerUpCount = currentWaveNumber * 3;
        Spawn ();

    }

    void Update(){
        CheckifReadySpawn ();
    }


    void Spawn ()
    {
        Debug.Log ("spawm" + currentWaveNumber);
        for (int i = 0; i < 10; i++) {
            var enemyGameobject = (GameObject)Instantiate (Power, randomSpawnPoint, Quaternion.identity);

        }
    }

    void CheckifReadySpawn ()
    {
        if (currentPowerUpCount <= 0) {
            currentWaveNumber++;
            currentPowerUpCount = currentWaveNumber * 5;

            Invoke ("Spawn", spawnDelay);
        }
    }



}

This is the HealthIncrease (I add this to the cube)

public class HealthIncrease : MonoBehaviour {

    public UISlider healthBar;
    public GameObject player;
    // Use this for initialization
    void Start () {

    }

    // Update is called once per frame
    void OnTriggerEnter (Collider collider) {

    if (collider.CompareTag("Player"))
        PickItUp ();


    }

    void PickItUp ()
    {
        var playerStats = (Stats)player.GetComponent<Stats> ();
        if (playerStats.health >= 500) {
            return;
        }
        else {
            playerStats.health += 50;
            Destroy (this.gameObject);
            healthBar.value = playerStats.health / 500;
        }
    }


}

Answer 1

I'm guessing the prefab for the pickup does not have a collider on it. Note: for collision to work at least one of the objects needs to have a rigidbody and both need to have colliders.