How long can I keep a jar of pre-chopped ginger? Can I freeze it?

I cover my ginger, as the Chinese do, with rice wine or dry sherry. Lasts a very long time that way and you can use the liquid in marinades & sauces.

There also is no reason u couldn't freeze it to have it available whenever u want it.

I've held chopped ginger both covered in olive oil and just in a ziplock alone, and both results were identical. Moral of the story: Ginger is very forgiving and you can hold it for a good week. Alternatively, it's relatively inexpensive, so a loss isn't all that great.