Guardians only spawn in ocean monuments, which themselves only spawn in deep ocean biomes. Guardians spawn in water blocks within a 57×24×57 volume defined horizontally by the base of the monument and vertically from the floor level of the monument (usually if not always Y=39) up to just above the decorative structure at the top (usually if not always Y=61).
Preparing the monument
Before creating a farm, the player must conquer an ocean monument.
To force guardians to spawn within the farm itself, it may be helpful to remove all other water from the spawning zone. Keep in mind that this is a tedious job and may take many resources and a lot of time to accomplish, as well as guardians being present throughout the process, making this job difficult without good armor. Invisibility potions work against the guardians if the user isn't wearing any armor, but guardians will notice them if they get very close.
- Inside the monument, sponges are very useful: most rooms can be cleared by placing sponges spread across the ceiling, and then repeating lower down if necessary. Larger rooms (e.g. the core and the more open wing) may need to be partitioned before draining to prevent flooding.
- Another way to clear the water can be done before the elder guardians are dead; fill each room with TNT, starting at the top and following the water level down. TNT blocks can be broken instantly, even with Mining Fatigue III. Like with sponges, partition your work area.
- Outside the monument, options include:
- Build a wall around the monument (around 87 full stacks will be needed; sand or gravel may be preferred as they can be placed from above to fall to the sea floor), and then use sand or gravel to fill in the inside. This could be sped up by using this contraption
- Build a wall as above, then use sponges to progressively remove the water. Partitioning may be used to allow for manageable areas to be cleared, or pistons may be used to push sponges into the water simultaneously across the width of the monument.
- Build a ring, flood the inside with lava to turn a layer of water to stone, extend the ring down, mine out the stone, and repeat. This has the advantage of a much lower initial resource cost, although the mining will take a long time and will use a large number of pickaxes to mine all of the stone out.
- Using a wall surrounding the monument area, fill in all the water with flammable materials such as leaves and wood planks. Once done, light it on fire for quick clearing.
- Build a wall, then use a piston-and-slime block machine (e.g. the "MOSES" machine) to clear the water. You can also use this machine to remove the water.
- Build a ceiling, then use frost walker enchantment to freeze the water and then mine it.
If the design is to kill guardians with fall damage or to have the player AFK near the bottom of the farm, all undersea caves (and any nearby islands) within a 128-block radius will need to be lit, slabbed, or flooded to prevent other hostile mobs from filling the mob cap. Alternatively, an AFK spot high above the monument (Y=160 to Y=170) may be used so only the monument is within the 128-block-radius sphere.
A basic guardian farm design usually involves a spawning area, a killing area, a method for transporting the mobs from the spawning area to the killing area, an item collection system, and a place for the player to wait.
As guardians spawn underwater, the spawning area must be flooded. The simplest designs involve simply placing a layer of signs under a pool of water a few blocks deep (either existing ocean or a pool newly constructed) and relying on the Guardians swimming or sinking too low and falling out of the water.
As guardians can spawn in flowing water, more active designs have downward-flowing water to push the Guardians more quickly out of the spawning area. As downward-flowing water requires an adjacent wall to exert force on mobs, these designs will typically have either a series of 2-block-wide pools or blocks placed within the spawning area.
Downwards bubble columns may also be used to drag the spawned guardians down. However, the magma blocks will not do any actual damage to the guardians, as they are immune to this type of damage (this does not seem to be true as of 1.15.2)
Because guardian spawning is severely inhibited when the water block selected for a spawning attempt has a view of the sky, putting a roof over the water spawning area will increase the spawning rate.
Transport and killing
The simplest design is to leave a large room below the spawning pool. Guardians can also be easily transported by flowing water, so the usual canal or flowing-pool designs can be used to collect them into a central area for more concentrated killing.
While manual kill designs are possible, keep in mind that the Guardians' natural thorns damage will damage players using swords rather than arrows or damaging potions, and that guardians can fit through 1-block holes (thus attacking from above or around a slab or other small gap is needed to prevent escapees). A manual-kill Guardian farm should thus provide for healing, either a beacon providing regeneration or potions. Having a health of 30 × 15, Guardians will require a 34-block drop to kill. Lava over a 12-block drop is sufficient to kill with a combination of fall, lava, and fire damage.
Iron golem kill designs do work, but are limited in usefulness as the guardians' thorns effect will eventually kill the golems, requiring regular replacements. This makes such a method very difficult to maintain without an iron farm.
Suffocation traps are possible, however, guardians may phase out through corners. To prevent this, add extra blocks to the corner.
It is possible to use full-stand conduits to kill guardians, however, the guardian must be 8 blocks from the conduit itself, and the conduit must be in water, making it possibly hard to collect drops.
Item collection and waiting
Guardian farms present few unique issues with respect to item collection and player waiting areas: hoppers or hopper minecart systems work well for collection, and except for manual-kill concerns mentioned above nothing special is required for a player waiting area.
This design transports guardians to a collection pit, where they are then damaged with splash poison and instant damage potions. You can then collect the drops, either by hand, or hopper.
No Drain Guardian Farms
Many farms Pre Update Aquatic require you to drain the monument prior to making your farm
Since 1.13 you can now avoid draining. An example is here:
These No Drain Guardian farms are time efficient as they use the new 1.13 mechanics of soul sand to launch guardians upwards into a chamber that then directs them in various ways to a kill chamber, often using both lava and gravity. The size of the soul sand section can vary from just a small square to the full 56x56 area of the monument, with the bigger area giving greater drops and yields. The area from the monument floor to the surface must be completely clear to avoid any blocking of the guardians ascent to the chamber which is often situated at the ocean surface. Note that large blocks of bubble columns can massively lower your FPS unless particles are set to minimal.
One of them is the iron golem method, where guardians spawn and are funneled using water currents to a trench filled with iron golems. As the iron golems attack the guardians, the drops are collected using hoppers and deposited in chests. This method is fairly iron-heavy, due to all of the iron golems, which will need to be periodically replaced due to the guardian's spike damage, and a large amount of hoppers used.
Another farm is the 'OP', or super-efficient farm. This farm is very expensive to build in Survival mode, due to the amount of materials used, but produces over 100,000 items per hour.
Similar to the iron golem-based farm, except there is a drop down to bedrock instead of hoppers, some lava near the bottom to ensure no guardians are still alive, and a hopper minecart to collect the drops. An estimated raw resource count is:
- 200+ solid blocks
- 6.5 stacks of wood logs
- 80 iron ingots
- 6+ gold ingots
- 55 redstone
- 12 diamonds (for pickaxes)
- 1+ sand (for glass)
- 1. Build an iron golem-based farm without hoppers or golems (see above).
- 2. Dig the central canal down to bedrock.
- 3. Place down rails covering the canal, with powered rails every 20 blocks (recommended, although you could have up to 50 blocks spacing).
- 4. Place redstone blocks under every powered rail except one (near a wall), then carve out a small room near the rail without power.
- 5. Place a lever next to the unpowered rail, and a hopper underneath. Place 2 chests next to the hopper, make sure they are connected to the hopper. The lever should connect to the rail.
- 6. Place some glass overlooking the rails, place down the hopper minecart, and you are done. For more storage, place down more hoppers and chests.
A simple farm that uses a conduit to kill guardians, which allows spawning and killing to be done in the same room.
- Drain the temple
- Create a large, flat room
- Put a single layer of water over every block in the room, flowing to a single point to be optimal
- Put a hopper at the point(s) that the water flows to, connected to a storage system
- Activate a conduit directly underneath the center of the room. if there are no hoppers there and the floor is made of prismarine, the floor could be used as the top of the activation frame