String is one of those resources you never think about until you need a stack of it for wool, beds, leads, fishing rods, scaffolding, or crossbows. It is also one of the easier drops to farm, but "farm a spider" hides a real design problem: spiders are shaped and behave nothing like the zombies and skeletons most farm tutorials assume. In Minecraft 26.3 Java Edition there are two genuinely different ways to farm them: a dedicated spider spawner, and a general mob farm that collects string as a byproduct. They are not the same build with different paint, they solve different problems, and this guide keeps them separate.
This guide ranks the options and walks through the spider-spawner build. It is part of our Minecraft farm guides collection for 26.3.
Rate0-2 string/kill (0-5 at Looting III)
XP level5 per kill
Build time15-25 min
DifficultyBeginner
Checked for: Minecraft 26.3, Java Edition (checked against the 26.3 changelog: none of these mechanics changed from 26.2), vanilla survival. Spawner rates are documented behavior; output depends on how well you light the surrounding caves so the spawner is the only spider source in range.
Why spiders are awkward to farm
Every other common mob farm (zombies, skeletons, even cave spiders to an extent) works because the mob is roughly a 1-block-wide column that funnels down a hole or through a 1-block gap. Spiders break that assumption:
- They are 1.4 blocks wide and 0.9 blocks tall, the opposite proportions of a normal mob: short and wide instead of tall and narrow. A gap sized to stop a zombie (1 block wide) does nothing to a spider, since a spider's hitbox is wider than that gap in the first place, and a gap sized to fit a spider (1.4 blocks) lets nearly everything else through too.
- They climb. Spiders can scale any solid vertical surface, so a plain drop shaft that works for a skeleton just becomes a wall a spider walks back up.
- They fit through gaps other mobs cannot, because at 0.9 blocks tall they can enter spaces that would block a 2-block-tall zombie or skeleton entirely.
That combination, wide instead of tall, able to climb, and able to fit through a low gap, is why a string farm needs water flow and climb-proof surfaces rather than a simple 1-block trapdoor filter. It is the whole design problem this article is about.
Where string comes from
String drops from:
- Spiders, 0-2 string per kill at a 66.67% chance to drop any (average 1.00 string per kill), rising to 0-5 string at a 94.44% chance with Looting III (average 2.50 per kill). The main farmable source.
- Cave spiders, the same 0-2 (no Looting) to 0-5 (Looting III) string range as ordinary spiders.
- Spider eyes, a separate roll on the same kill: 0-1 at a 33.33% chance without Looting (average 0.33), rising to 0-4 at 88.89% with Looting III (average 1.83). Only on a player or tamed-wolf kill, same restriction as string.
- Cobwebs broken with a sword or shears, which yield string.
- Bartering with piglins, as an occasional minor return (not efficient for string specifically).
- Cats, as an occasional gift, and fishing, as junk (both incidental).
For volume, you want spiders. The two practical builds are a spider spawner farm and a general mob farm that collects string alongside everything else, and they differ enough in mechanics to cover separately.
What string is actually for, and which of those justify a farm
String has a lot of uses, but they are not equally demanding:
Pros
- Wool substitute (looms need 1 string), cheap and renewable without keeping sheep
- Beds (1 string per bed), a one-time cost per bed you own
- Bows and crossbows, 2-3 string each, again a one-time craft
- Fishing rods, 2 string, one-time
Cons
- Leads (4 string each) if you keep a lot of animals, this adds up but slowly
- Scaffolding, cheap per-piece but scaffolding towers can eat dozens of string on a big build
- Tripwire, situational, rarely the reason to build a farm
None of the one-time crafts (a bed, a bow, a fishing rod) justify a dedicated farm on their own; a handful of cobwebs or a lucky cave clear covers them. What actually justifies a spider farm is ongoing bulk consumption: scaffolding for a large build, or wool for a build that would otherwise need a big sheep pen, since wool from a loom needs both string and wool itself so this only helps the string half. If your string need is a one-time stock-up, skip the farm and just clear a few cobweb-filled mineshaft rooms.
Option 1: spider spawner farm (fastest, needs a rare structure)
If you have found a spider or cave spider dungeon spawner, it is the best dedicated string source: a fixed spawn point that produces spiders continuously as long as a player is in range and the area is dark. There is no way to place your own spider spawner in survival, and unlike a Nether fortress (guaranteed to generate with a blaze spawner), an overworld dungeon or mineshaft spawner is not guaranteed anywhere near your base. Finding one reliably means exploring, not building: check dungeons (25% chance to be a spider spawner rather than a zombie or skeleton one) and mineshaft corridors (cave spiders, usually surrounded by existing cobwebs), or search a spawn finder/seed map if you are willing to look one up rather than explore blind. If you never find one, option 2 below covers you.
The build:
- Light the surrounding caves. A spawner only runs at full rate when it is the only valid spawn surface in range. Light every nearby cave so all spider spawns happen at your spawner.
- Enclose the spawner room. Keep it dark inside the spawner's activation range so it keeps producing.
- Funnel the spiders. Given the 1.4-wide, 0.9-tall hitbox and wall-climbing, a string farm uses water streams plus a flushing system, not a narrow trapdoor gap, to move spiders to the kill point. Water push works regardless of the spider's odd shape; a geometric filter does not.
- Collect. Hoppers under the kill area feed string and spider eyes into chests.
Spiders can climb walls and squeeze through gaps that would stop a zombie or skeleton, so a string farm needs more care than either of those farms. Use water to push them and an overhang or trapdoor lip so they cannot climb back out of the kill area once they are in the water stream.
Cave spiders are noticeably smaller: 0.7 blocks tall and 0.7 blocks wide, small enough to fit under a single slab, which regular 0.9-block-tall spiders cannot always do depending on the gap. That makes a cave spider kill chamber easier to seal small, but cave spiders are also poisonous (their poison lasts 7 seconds and deals 6 damage total on Normal difficulty, or 15 seconds and 12 damage on Hard), so the smaller size cuts both ways: it is easier to build a tight kill box, but that same tightness means you must be certain no gap lets a cave spider reach you, since poison stacks with whatever else is hitting you.
Option 2: general mob farm (no spawner needed)
If you have no spider spawner, the simplest answer is a general mob farm. A dark-room grinder spawns spiders alongside zombies, skeletons, and creepers, so you collect string as part of the mix along with bones, gunpowder, and arrows. Spiders need light level 0 to spawn naturally (stricter than the light level 7-or-below threshold most other overworld hostiles use), so a mob farm's usual pitch-dark spawning floor already meets that requirement without extra work; the tradeoff is that a general mob farm's kill mechanism (typically a fall-damage drop with a 1-block finishing gap) is built around zombies and skeletons, not the wide, climbing-capable spider, so expect spider string yield to be lower per-hour than a dedicated spider spawner even though the raw drop math per kill is identical.
This is less string-dense than a dedicated spawner, but it requires no rare spawner and gives you a pile of other useful drops at the same time. For most players without a spawner, the general mob farm is the right call.
Option 3: the easy alternatives
- Cobwebs. Found in mineshafts and ancient cities, broken with a sword they drop string. Not renewable, but a quick early stack.
- Cats. A tamed cat occasionally gifts string when you sleep. Trivial, but free if you keep cats.
These are stopgaps, not farms. For any real volume use a spawner or a mob farm.
AFK placement and chunk loading
A spawner runs while a player is within 16 blocks of it (spawner activation range) and the chunk is loaded. A dark-room farm follows the usual 24-128 block spawning spheres. Either way, keep your AFK spot in range and force-load the chunks for passive operation:
/forceload add <farm-x> <farm-z>
The Mob Spawner Optimizer helps you place the AFK point correctly, and the chunk borders and forceload guide explains the ticket levels a passive farm needs.
A spider farm is lighter than a full mob grinder, but any spawning farm adds entity load. If you run a server, size it with the Server RAM Calculator and pick a host on real entity performance with the hosting comparison. The lag and stutter guide covers the settings that help if a single-player world chugs near the farm.
Common mistakes
Spawner barely produces. The surrounding caves are not lit, so spiders spawn there instead of at your spawner. Light everything in range so the spawner is the only spider source.
Spiders climb out of the farm. No overhang or climb-proof lip. Add a trapdoor or block overhang so spiders cannot scale the walls back out of the kill area.
Cave spiders poisoning you. The kill chamber lets them reach your position. Seal it completely; at 0.7 blocks tall and wide, cave spiders fit through gaps that would block almost anything else.
Farm stops when you move. You left the spawner's 16-block range or the chunks left simulation distance. Stay close to a spawner farm and force-load the chunks.
Kill mechanism built for zombies, not spiders. A 1-block trapdoor gap or narrow drop shaft assumes a tall, narrow mob. Spiders are 1.4 blocks wide and 0.9 tall, so that filter either blocks them outright or does nothing; use water flow to move them instead of relying on a gap.
A spider spawner is also a foundation for an XP farm, since you can kill the spiders yourself for experience. For a no-spawner approach that collects string among many drops, build the general mob farm.
This guide is part of our Minecraft farm guides collection for 26.3.
Frequently asked questions
What is the fastest way to farm string in Minecraft 26.3?
A spider or cave spider spawner converted into a farm is the fastest dedicated string source. Light the surrounding caves so the spawner is the only spider source in range, funnel the spiders with water, and collect the string with hoppers.
How do I farm string without a spider spawner?
Build a general dark-room mob farm. It spawns spiders alongside other hostile mobs, so you collect string together with bones, gunpowder, and arrows, no rare spawner required.
Why is my spider spawner farm so slow?
Almost always unlit caves nearby stealing spawns. A spawner only produces at full rate when it is the only valid spawn surface in range, so light every cave around it.
How do you stop spiders climbing out of a string farm?
Add an overhang or trapdoor lip above the walls so spiders cannot scale back out of the kill area, and use water streams to push them toward the kill point rather than relying on gravity alone.
How much string does a spider actually drop?
0-2 string per kill with a 66.67% chance of getting any (roughly 1.00 string on average) without Looting, rising to 0-5 string at a 94.44% chance (roughly 2.50 on average) with Looting III. Cave spiders drop the same range. Spiders also have a separate chance to drop a spider eye: 0-1 without Looting (33.33% chance) up to 0-4 with Looting III (88.89% chance), but only when killed by a player or tamed wolf.
Is a spider spawner or a general mob farm better for string?
A spawner is denser for string specifically, since every kill is a spider. A general mob farm gives you less string per hour because spiders are only one of several mobs it spawns, but it needs no rare spawner and returns bones, gunpowder, and arrows at the same time. If you already have a mob farm running and just need occasional string, it usually is not worth also hunting for a spawner.
Do I actually need a spider farm, or will cobwebs do?
If your string need is a handful of beds, a bow, and a fishing rod, cobwebs from a couple of mineshaft rooms cover it without any building. A farm only pays off for ongoing bulk use: large-scale scaffolding, or wool production via looms on a build that would otherwise need a big sheep pen.
Sources & further reading:
