A life-bearing planet similar to Earth. Sometimes used in the narrow sense of a world habitable to humans and other Terragen bionts, but also used more generally for any planet with a complex biosphere and macroscopic life forms. Naturally evolved garden worlds are rare; most garden worlds within the Terragen sphere have been engineered by Terragens or xenosoponts. Natural garden worlds may be divided into worlds with macroscopic life only in the oceans, and worlds that also have macroscopic life on land. Worlds with primitive unicellular, protobiotic or noncellular life are not generally considered to be garden worlds.
The term natural garden world is often reserved for worlds with biospheres that have evolved without any known interference since the planet's formation, although worlds which have been terraformed in the distant past by various xenosophonts are often included. Some planetologists even include worlds that have been terraformed by Terragen colonists and do not require maintenance, although this is not the general consensus.
Colonisation of natural garden worlds is generally restricted, especially if a Caretaker God has claimed the word as a protectorate. In most cases the local biology is not compatible with terragen biochemistry, although this can be overcome by the application of advanced biotechnology.