Does Blood Sun keep me from turning my Zoetic Cavern face up?

Question

Does Zoetic Cavern lose its morph ability when face-down keeping it from being able to turn face-up when there is a Blood Sun in play?

Answer 1

There is a ruling on Zoetic Cavern that states:

If Blood Moon is on the battlefield and a player controls a face-down Zoetic Cavern, it can’t be turned face up since it won’t have a morph cost.

This ruling comes from rule 702.36e, which states among other things:

If the permanent wouldn’t have a morph cost if it were face up, it can’t be turned face up this way.

So the Sun stops your Cavern from being turned face up.