Strange Plant

Strange Plants exist to be handed to the Dye Trader. Once you are in Hardmode his dialogue gains an option for them, and each plant you turn in gets you a batch of one random dye that has no other source anywhere in the game. There are 33 of these to collect and the pool widens as you clear more of the game, so early turn ins draw from a smaller set. You can hand over a whole stack in one sitting without losing anything. Never sell the plant itself, the dyes it converts into are worth far more.

They need dirt, grass grown on dirt, or mossy stone, and they turn up at any depth except the Underworld. The rest of the rules are about spacing. One plant blocks another from growing for a long way in both directions, they avoid the true edges of the map, and on the surface and in space they skip the middle fifth of the world entirely. That middle restriction goes away underground and in the caverns. Remix and Zenith worlds allow the middle band up top, just rarely. Lava and honey stop them completely.

• A Spelunker Potion highlights them like ore, which makes a fast surface run the best sweep you can do.
• A Metal Detector picks them up as well.
• Floating Islands grow them and almost nobody goes back up there, so a tour of the sky usually pays for itself.
• The plant looks like a three by three clump but only the bottom center tile is real. Mine that tile or you get nothing.
• They will not go in a Clay Pot, and in Journey Mode each type has to be researched on its own.

A long flat run of bare dirt built above the ground works well, since they are happy on grassless soil. Leave it bare on purpose, because grass sprouts weeds and flowers that eat the spawn slots. The same strip doubles as a Blinkroot farm. One thing worth knowing before Hardmode: picking up a Strange Plant counts toward the Dye Trader moving in, so one found early is not wasted even though you cannot turn it in yet.