Terraria Community Forums

Be in Hardmode. Be in Ice Biome. Kill shiz. Done.

Ok thanks

And does it matter if it is a ice biome mixed with a crimson biome??

I don't think so. I wouldn't mind getting a Crimson Mold anyhow.

Just to be sure, if you're aiming only for the Frozen Key Mold, it might be best to use a pure one. If you want both, use both at the same time, otherwise an extra drop in the loot table might just infuriate you, where you keep getting the Crimson one, instead of Frozen.

Does plantera have to be defeated or no

I believe not. The Wiki can answer these questions much better than I can. And I see you're a Pennsylvanian, hullo! I reside there myself.