In my experience, they germinate best regardless of depth. I've had them germinate fine on the surface, a bit under the surface, and in a wet paper towel.

Good luck. :)

Thanks i'll try on the surface i think as i heard light can help them germinate.

LOL.. Passi seeds can take bloody ages to sprout no matter what you do- hence all the rumors of what works best. WHen I first started (sheesh, can it be?) 12 years ago I couldn't get any to sprout to save my life. I soaked 'em in all kinds of fluids, put 'em on the surface, buried 'em, used a heat mat, sang to 'em, scarified 'em.. About the only thing I didn't do was smoke 'em.

Still, nothing happened. I finally gave up & for many years I simply bought clones. Only in the past 3 years have I gotten into seeds again- And the 1 thing I've learned to make 'em sprout? Patience.
Some sprout in a week, yeah. I've seen some take 2 years or more.. I have a couple right now in the back yard- Volunteers. NO idea what they are as that's where I throw my old seed starting mix. WHoever moves in will get to see what they are- If they don't whack 'em down as a weed.

So how do I do it? Cross my fingers & toes & keep breathing as I wait. That's it.