I am in a slime chunk and it is pitch black down there and I made a farm with cacti and an iron golem. I don't really care if it even works. I just want slimes to spawn. My farm is on y level 55 in a swamp biome and I stand 24 blocks away from my farm when I afk it. The ravine nearby is lit up like a kid's face on Christmas. Mobs are spawning in my farm (but no slimes). I think these mobs are preventing the slimes from spawning but I do not know how to get rid of the mobs so that slimes can spawn but mobs do not.
1What do you mean by Slime Chunk?– GingeMar 2, 2019 at 16:54
1A slime chunk... You know a chunk that spawns slimes– user228104Mar 2, 2019 at 19:29
So a slime spawner– GingeMar 2, 2019 at 22:19
5@Ginge a slime chunk is an area of land that spawns slimes freely minecraft.gamepedia.com/Slime#.22Slime_chunks.22– BenMar 2, 2019 at 23:24
Firstly, use a slime chunk finder to make sure you're in the right area. You can enter your seed into the tool, and it will locate the chunks on your world that are slime chunks.
Secondly, light levels do not affect slime spawning in these designated slime chunks. They will still spawn at light levels above light level 7, when other mobs do not.
And finally, you will need to light up the surrounding areas underground, to increase the spawn rates of your farm.
Edit: An important fact that I failed to add (thanks to SF for pointing it out), Slime chunks will only spawn Slimes at levels below Y:40 (unless you're in a swamp biome). This means to gain any real productivity from this farm, you will need to dig all the way down to bedrock, and build the farm up from there.
OK I will light up the chunk and also I did use a slime chunk finder called chunk base AND Mine Atlas and both stated there was a slime chunk there. I lit up the ravine around and will now light up the room. Thank You Mar 3, 2019 at 16:16
2Let's add either you use spawning of the swamp biome, Y = 50..70 in light levels of 7 or less, or you use slime chunk spawning, Y < 40, any light level. If you're in a swamp biome near the surface but in a slime chunk, the slime chunk will actually interfere with your farm, spawning slimes in the caverns below and filling up the mob cap.– SF.Mar 4, 2019 at 16:04
In a slime chunk, slimes spawn below Y-level 40 (Source: Minecraft Wiki).
I think slimes only spawn in swamps at certain times. Get out of that swamp and make the farm in a slime chunk not in a swamp. Make sure you dig out the entire chunk because that does affect spawning rates.
Move your iron golem out of the chunk
3Can you explain why your answer works? What is the reasoning behind moving Iron Golems away?– 54DFeb 16, 2020 at 6:52