What are the requirements for growing liana vines in Terraria?
Solution 1:
I'm assuming you mean the vines, as you speak of dirt blocks, and the vines grow from those. They do look like liane.
The dirt block needs to have grass on it. And grass spreads from other grassy dirt blocks. Or, you can use grass seeds, or the Staff of Regrowth.
The only requirement I can find is just a grassy dirt block. Sunlight, underground/aboveground. It all doesn't matter.