I’m about to enter hardmode in Terraria and I want to control how the Corruption and Hallow spread. I know you’re supposed to dig 3-5 block long holes deep to the underworld on both sides of the map, but I’m unclear if 3 blocks is enough. Also, what’s the best way to fill these holes? Can someone walk me through the best way to prevent the biomes from spreading before and during early hardmode?
5 Answers
Also, just a heads-up, the Corruption and Hallow spread rates really ramp up before you defeat Plantera, so it’s worthwhile to get as much control done early on. Your gear sounds solid for rushing hardmode bosses, so I’d say go for it. After you get the Clentaminator from the Steampunker NPC who shows up after defeating the mechanical bosses, you can really take control over the biomes. Save up some platinum for it because it’s a bit pricey but totally worth it.
One more thing, some folks suggest moving NPCs to jungle or sky bases to protect them from corruption spread, but honestly that’s a lot of extra work since you’ll have to build new homes for them. Just focus on shielding your existing villages with trenches and non-corruptible blocks. Keep your current NPCs safe and let the Clentaminator handle the biome spreading once you’re ready.
Honestly, trying to fully contain the spread of Corruption and Hallow right when you hit hardmode is super tough. The world actually generates a big new chunk of evil and hallow on hardmode start, so predicting or quarantining it perfectly is basically impossible. Instead, focus on protecting your NPC villages by digging trenches around them and lining the walls with blocks that corruption can’t spread through — stuff like clay or stone bricks work great. Once you defeat the mechanical bosses, you can get the Clentaminator, which is the best way to control biome spread. And if things really get messy, converting your NPC areas into Hallow is a good safe bet since NPCs don’t mind it and the Corruption won’t spread there easily.
To clarify the trenches, the holes should be just 3 to 5 blocks long and go deep enough to the underworld, but you don’t actually have to dig huge tunnels all the way through the world sides. The goal is to break the connection so the Corruption and Hallow can’t spread across them. Also, make sure to line those trenches with blocks that can’t be corrupted or hallowed like regular wood or stone bricks. This prevents the spread through vines or conversion.
About the Clentaminator, you’ll get access to it by beating all three mechanical bosses: The Twins, The Destroyer, and Skeletron Prime. Once you have it, it makes cleaning and controlling biome spread so much easier. So if you feel ready, rush those bosses. If your gear includes Night’s Edge sword, Molten Armor, Bundle of Balloons, Terraspark Boots, and Feral Claws, you’re in a pretty good spot to take them on. Just be sure to keep some healing potions and good movement options handy!
