Corrupt Seeds

Corrupt Seeds are Seeds which can be planted on Dirt Blocks and will then spread The Corruption in all directions. The corruption will only spread above sea level (positive elevation).

Corrupt Seeds drop from Eye of Cthulhu only on worlds with Corruption. Also sold by the Dryad during a Blood Moon.

The primary use of planting Corrupt Seeds is to Farm Vile Mushrooms.

Another use for Corrupt Seeds is to place Corruption on a world with Crimson, it is possible to do this on a new character and a new world with Crimson without needing to make multiple worlds, as even on a world with Crimson, you can still buy Corrupt Seeds from the Dryad during a Blood Moon.

Spread Warning
As a warning to players creating Corruption Farms or simply small patches of corruption, do note that Thorny Bushes will grow on player planted Corruption. Not only can these growths damage you, but they can reach up to 4 spaces across and upwards, spreading Corruption to anything it touches, potentially creating unwanted areas of corruption. It is recommended to either leave larger spaces between non-corrupt Grass/Dirt or to plant a Sunflower on the edges of where you wish it to spread to (obsolete in Hardmode).