I have played terraria for a while now but I have noticed that my corruption biome is spreading into my desert and I’m not sure if this is a good thing or a really bad thing. My question is how do I stop the spread of corruption easily for above and below ground? (for hardmode) Also all I know is that corruption spreads “3-6 blocks per day” is this irl? And does it spread faster or slower through sand?
According to the unofficial Terraria wiki,
The player can remove corrupt areas by using Purification Powder
The Clentaminator can [also] be used (with purchased solutions) to change blocks into the normal pure forest, the Hallow, the Crimson, or the Corruption.
Wood is a cheap but effective material for containing the Corruption or the Hallow.
Also see the the official Terraria wiki:
Purification Powder is able to revert any Corrupted … Blocks back into their pure form
Bonus option — Air works, too!
By digging at least a 3-block wide tunnel around your corruption/crimson/hallow, you can prevent it from spreading outside of the boundaries that you give it.