An iron farm is one of the most important and most worthwhile farms in all of Minecraft. Iron is a universal resource: you need it for hoppers, rails, shovels, pickaxes, armor, shields, anvils, chains and dozens of other items. Without a steady supply of iron, building more farms becomes practically impossible, so an iron golem farm should be one of your priorities right after you've secured a steady food source and a basic XP farm.

How iron golems spawn

Iron golems are big, friendly creatures that spawn naturally in villages and defend villagers from hostile mobs. A farm makes use of their spawn mechanic: an iron golem appears when at least three villagers "panic", meaning they see a threat such as a zombie or a pillager. Each villager needs an assigned bed (to count as part of the village) and a workstation (to have a profession, which keeps it active).

When the villagers panic, after a short while one of them "summons" an iron golem. The golem spawns within a few blocks of the villagers, on the platform we prepared for it. The mechanic repeats every few dozen seconds, which means a steady stream of golems, and each one drops 3-5 iron ingots when it dies.

Materials list

To build a basic iron farm you need the following materials, which you can craft or find by exploring the world:

3+ villagers - you can move them from a village in a boat or minecart, or breed them on the spot
3+ beds - every villager needs its own bed (wool from a wool farm + planks)
3+ workstations - any kind (composter, lectern, smithing table and so on)
1 zombie - caught in a minecart and given a name tag (so it doesn't despawn)
Minecart + rails - to transport and hold the zombie
Building blocks - about 200 (cobblestone, planks)
Water - buckets of water for the transport system
Lava - a bucket of lava for the kill system
Hoppers - 3-5 to collect the iron and poppies
Chests - to store the collected resources
Glass - for the wall between the villagers and the zombie (the villagers need to be able to see the zombie)

Step-by-step build

Start by building a platform a few blocks above the ground or in the air (a farm in the air is better because it prevents mobs from spawning on the ground). The platform should be at least 16x16 blocks, although 20x20 gives better results. In the middle of the platform, build an enclosed chamber for the villagers: a 3x3x3 space with a glass wall on the side where the zombie will be.

Inside the chamber, place the beds and workstations, then bring in the villagers. Opposite the glass wall, 1-2 blocks away, put the minecart with the zombie on rails. The villagers have to be able to see the zombie, but the zombie must not be able to attack them. Name the zombie with a name tag renamed at an anvil so it doesn't disappear. Any name will do, for example "Scarecrow".

The whole surface of the platform (except for the villager chamber) is the area where golems can spawn. Water along the edges of the platform flows toward a central opening. After a golem spawns, the water pushes it into the opening, where it drops into the kill system. At the bottom, set up a lava kill system: the lava kills the golem, and hoppers collect the iron and poppies it drops.

Warning: Iron golems are immune to drowning and fall damage. Lava is the most effective way to kill them. You can also use cacti or suffocation with pistons, but lava is the simplest to build.

Optimizing and scaling

A basic farm with 3 villagers produces around 40-60 iron ingots per hour, which is enough for most needs. If you need more, there are a few ways to improve it. The first and simplest is to add more villagers: 10-20 villagers raise the golem spawn rate considerably, because more villagers can panic and summon golems at the same time.

A more advanced method is stacking farms: you build several identical farms one above the other, each with its own set of villagers and zombie. All the kill systems feed into a single central collection point. A farm with 4 modules can produce more than 300 iron ingots per hour, enough to build practically anything. It's also worth knowing that you can turn surplus iron into nuggets or trade it to armorer villagers for emeralds.

The key rule when scaling: keep each farm module at least 16 blocks above or below the previous one so the golem spawning works independently in each.

Common mistakes and fixes

Plenty of people build an iron farm and find it doesn't work. Here are the most common causes:

The villagers have no beds - every villager has to "own" a bed. Place the beds, wait for night, and check that the villagers sleep.
The villagers can't see the zombie - the glass wall has to give them a line of sight. Use plain glass, not stained glass.
Golems spawn outside the platform - make sure the platform is big enough and that there are no blocks nearby where a golem could appear.
Another village nearby - beds within 48 blocks can disrupt the mechanic. Remove all the beds from the area.
The zombie disappeared - an unnamed zombie despawns. Always name it with a name tag at an anvil.

An iron farm is the foundation of every advanced base in Minecraft. Without one, building redstone contraptions, more farms or even mass-producing items is a lot slower. Once it's built, it produces iron around the clock as long as you're within range of the loaded chunks. For more on chunk loading and farm optimization, see the chapter on tips and optimization.

Tip: Even a simple farm with 3 villagers gives you enough iron for everyday needs. You don't have to build a mega farm right away: start with the simple version and expand it as you need. You can also use the iron from the farm to build hoppers, which are an essential component of practically every other automatic farm.