Can corrupt thorns spread (corrupt) grass?

[Laluzi]

I know that corrupt thorns are corrupt blocks, and that in hardmode they'll convert any corruptible blocks within a 3-tile radius and all that jazz. That isn't what I'm asking.

I'd never noticed this happen before, but I was digging a 3-tile-wide containment tunnel (in pre-hardmode), where one side of the tunnel was corrupt grass, and the other side was bare dirt, with no grass able to reach it from the surface. The tunnel stretched down to about -200 feet and the corrupt grass was eventually cut off with clay/ebonstone, so it couldn't have climbed around the bottom of the tunnel to reach the bare dirt side. I knew that corrupt thorns could grow from the corrupt grass, but seeing as nothing corruptible was on the other side of the tunnel, I didn't think that was a concern.

A few in-game weeks later, I happened to check my map and found that, in addition to the thorns having grown, most of the clean side of the tunnel was now covered in corrupt grass.

I don't think I missed any grass seeds on the clean side, I didn't find any when I went back to check, so are corrupt thorns capable of spreading corrupt grass on dirt that they touch?

[baiits]

Yeah

[Laluzi]

Welp. Wish the wiki had told me that. Still, good to know - explains some containment breaches in the past. Thanks for the prompt answer.

[baiits]

Happy to help

[Syke]

Originally posted by TerrariaWiki:

Thorny bushes can grow six tiles in all directions (not just upwards). The Corruption variant of Thorny bushes spreads corruption, and the Crimson variant spreads crimson. Thorny bushes cannot grow over or otherwise affect vines. Therefore, vines can prevent the propagation of Corruption and Crimson across large gaps that would otherwise require careful maintenance.

Basically, thorn bushes can corrupt and can grow over gaps, but you can use vines to prevent this. Since vines don't have a corruption varient, this is 100% safe.

[Laluzi]

Originally posted by FriendlyPsychopath:

Originally posted by TerrariaWiki:

Thorny bushes can grow six tiles in all directions (not just upwards). The Corruption variant of Thorny bushes spreads corruption, and the Crimson variant spreads crimson. Thorny bushes cannot grow over or otherwise affect vines. Therefore, vines can prevent the propagation of Corruption and Crimson across large gaps that would otherwise require careful maintenance.

Basically, thorn bushes can corrupt and can grow over gaps, but you can use vines to prevent this. Since vines don't have a crimson varient, this is 100% safe.

While this is technically true, it's easier to just not deal with thorns at all by cleaning the grass from the corrupt side of any given tunnel, and removing anything that could become corrupt grass (this particular world had both corruption areas overlap the underground jungle, which is my favorite to deal with.) Since vines only travel 10 blocks down and can be destroyed while passing through, and that opens room for the thorns to grow back faster. I mean, this happened because I saw a really long face of grass and got lazy about cleaning it manually - covering it with stone would have done the trick.

Just to check, do crimson vines also spread crimson grass on bare dirt that they touch?