Iron Farm — 3D Build Guide
Three villagers see a zombie, call an iron golem, the water carries it into lava.
A compact iron farm on three villagers and one zombie, built block by block in 3D. The layout was built and run on a vanilla Minecraft 26.3 server before it got here: the villagers sleep every night, every golem reaches the lava, about 57 iron ingots per in-game day (about 170 an hour).
How to build the iron farm, step by step
- Chest and hoppers — Place a double chest, and four hoppers above it in a 2×2: the two over the chest point down into it, the two behind point into them.
- Kill chamber — Build a ring of cobblestone three blocks high around the hoppers. The golem will stand on the hoppers with its head in the top layer.
- Lava blade — On the inside of the ring, at the middle height, put a sign on the wall in each of the four cells, then pour lava into the four cells above them. The signs hold the lava up, and a golem falls through them: they have no collision.
- Platform — Over the chamber build a cross of cobblestone: four arms, two blocks wide and six long, around a 2×2 hole above the lava. Golems will appear on this floor.
- Walls of panes — Surround the cross with a glass block on the floor level and three glass panes on top of it. Golems never spawn on glass or panes.
- Signs in the hole — Put a sign in each of the four hole cells at floor level, on the floor block next to it. They keep the water from pouring into the lava, and the golem falls straight through.
- Water — Pour two water sources at the end of every arm. The water runs to the hole over the signs and pushes every golem into it.
- Villager cells — Three blocks above the platform floor (room for a golem under them), build three cells around the hole: west, east and north. In each, a bed with its head next to a window, glass under it, around it and over it. The window is two glass blocks with an oak trapdoor on top, placed in the top half and left closed.
- Night shutter — Put an inverted daylight detector on every trapdoor (right-click it once, it turns blue), and a glass block above it with one block of air between. At night the detectors open the trapdoors, the villagers lose sight of the zombie and go to bed.
- Villagers — Bring one villager into each cell, by boat or minecart, and let it claim the bed.
- Zombie in a boat — Over the centre of the hole, level with the beds, put a 2×2 of glass, place a boat on it and get a zombie into it. Three blocks above the glass put four cobblestone blocks, and glass on top of them.
- The farm at work — While the villagers are awake, about one golem appears every 30 seconds; it walks to the zombie with the water, falls into the lava and drops its iron into the hoppers. The test build made 57 iron ingots and 10 poppies per in-game day — about 170 iron an hour. Stay within simulation distance.
Iron farm — questions
How do villagers spawn iron golems in Minecraft?
A villager that panics tries to call a golem every 5 seconds. It works when at least 3 villagers within 10 blocks of it want one: each has slept in a bed in the last 20 minutes and has not seen a golem in the last 30 seconds. A zombie within 8 blocks that they can see makes them panic.
Why does my iron farm not spawn golems?
Check three things. The villagers must see the zombie: any block between them blocks the view, glass included. They must sleep: a villager that sees a zombie all night never goes to bed, so this farm hides the zombie at night. And no golem may stay alive near them — one stuck golem stops the farm.
Do iron farm villagers need beds?
Yes. Since a villager only wants a golem if it slept in the last 20 minutes (24000 game ticks), each villager needs its own bed it can sleep in. The farm keeps them standing on their beds.
How much iron does this farm make?
On a vanilla 26.3 server it made 57 iron ingots and 10 poppies per in-game day, about 170 iron an hour. A golem drops 3 to 5 iron ingots and 0 to 2 poppies; the farm makes about one golem every 30 seconds while the villagers are awake.
Why glass panes and not glass blocks around the platform?
A golem is 1.4 blocks wide and appears in the middle of a block, so in a 2-wide arm it overlaps the wall by 0.2 blocks. The game does not check that when it spawns the golem: against a glass block it gets stuck for good. A pane is only a thin plate in the middle of its block. Golems also never spawn on glass or panes.
Why is the zombie in a boat?
A zombie in a boat cannot walk out and never despawns, because the game keeps any mob that rides something. A block over it keeps the sun off, or it would burn in the morning.