You can configure these flags inside your config.yml file. Options: default_list, display_list
Wilderness flags can be edited in the /lands admin menu menu.

Reset flag(s) to their defined state from config.yml:

/Lands admin land <land | *> resetFlag <flag | all>
Keep in mind that changing flags in the configuration files requires a server reload / restart.

• ENTITY_GRIEFING
  Allow entities to grief blocks?

• TNT_GRIEFING
  Allow tnt to destroy blocks?

• PISTON_GRIEFING
  Allow pistons from a wilderness to push into the area?
  This should be set to false, since it protects against griefing from other players.

• MONSTER_SPAWN
  Should monsters spawn? This does not include spawners by default.
  To include spawners, you need to enable the include-spawners option.

• PHANTOM_SPAWN
  Should phantoms spawn? This does not include spawners by default.
  To include spawners, you need to enable the include-spawners option.

• ANIMAL_SPAWN
  Should animals spawn? This does not include spawners.

• WATERFLOW_ALLOW
  Allow water to flow? This should be set to false, since it protects against griefing from other players.

• FIRE_SPREAD
  Should fire spread? Fire can not spread from wilderness into lands, even without this flag being set.

• LEAF_DECAY
  Should leaves decay?

• PLANT_GROWTH
  Should plants (including trees) grow?

• SNOW_MELT
  Should snow and ice be able to melt?

• BLOCK_SPREADING
  Should blocks, such as amethyst blocks be able to spread into an area? This only affects blocks that are spreading from an area that is part of the same land. Blocks from the wilderness can never spread into claims, regardless of whether this flag is set or not.

These flags might not appear in the natural flag's menu. Instead, they usually have their own menu, where they can be toggled directly.

• TITLE_HIDE
  Hide the land enter title?

• REQUEST_ACCEPT
  Automatically accept new membership requests?

Here can add new flags.

  # Natural flags configuration. Role flags can be configured in the roles.yml file.
  # List of available landFlags: https://github.com/Angeschossen/Lands/wiki/Natural-Flags
  # NOTE: This option requires server reload / restart.
  land-flags:
    # Configure DEFAULT natural flags which will apply to new land creations.
    default_list:
      - monster_spawn
      - phantom_spawn
      - animal_spawn
      - leaf_decay
      - plant_growth
      - snow_melt

    # Natural flags which should be visible in the flags menu.
    display_list:
      - entity_griefing
      - tnt_griefing
      - piston_griefing
      - monster_spawn
      - phantom_spawn
      - animal_spawn
      - waterflow_allow
      - fire_spread
      - leaf_decay
      - plant_growth
      - snow_melt