Iphone alarm isn't coming through headphones?

I go to sleep with my headphones in and i set my alarm, but when it goes off the alarm goes off for a split second through the speakers then it goes to my headphones which i don't want, i want it to come out of my speakers. How do i change this?

Go to the home screen of your iPhone and unplug the headphones.
Turn the volume up, this will turn up the "sound effect" volume though the external speakers.
If you plug the headphones in and you can adjust the sound effect volume that is played though the headphones.

Unlike all other sound effects, the alarm will be played though the headphones and external speakers even if headphones are plugged in but only at the specified sound effect volume, so make sure you turn up the ones which you want to hear the alarm from.

Unplug the headphones.