From Starbounder - Starbound Wiki
Plant Block is an object unobtainable by players through normal means. This item's information is present in the game files, but not intended by developers to be in players' possession.
|Floran :||Floran feelss kinship with thiss plant block.|
|Glitch :||Fascinated. This block is completely constructed from plant matter.|
|Novakid :||Looks t'me like a block made outta plants.|