Minecraft wiki entry for End_survival, associated text: The player must bring the necessary materials and mobs from the Overworld to start. However, once these are in place, the player can make a colony so self-sustaining that it requires no transport to the Overworld for supplies. When enough Ender Dragons have been killed to open as many gateways as the player is comfortable with, they can start by taking with them some dirt (with optional grass blocks to make the islands more like the Overworld), a few buckets of water and lava, and seeds. Crops and trees can grow normally in the End (unlike the nether, which has fire hazards and no water for the crops) so they will not need anything done differently to care for them, as well as the cobblestone generator.