Oh.
Nevermind.
Drifter, I've mostly heard that lavendar is great for aromatherapy, but ingesting it?
The two herbs that are most commonly used to aid sleep are:
Valerian (you might need to visit a real herbal apothecary shop to find it)
Chamomile (kinda fun to grow--tastes a bit queer)
Being a scientific type, I'm sure you've looked into it already. Valerian was used in Britain during WWII to help with all the Londoners shaken up by the Blitz. (It's the root you use, so don't just pick the flowers and grind them)