You cannot breed spiders in Minecraft, because spiders are hostile mobs and do not have a breeding mechanic at all.
If you want more spiders, you need to rely on spawning, spawners, or mob farms.

That also applies to cave spiders, which are a separate mob type and still cannot be bred.
If you see spiders grouped together, they spawned there or came from a spawner, not from breeding.
The Short Answer

You cannot breed spiders in Minecraft. This includes both regular spiders and cave spiders, which are hostile mobs and do not use any feeding or love mode system.
Regular Spiders Do Not Have A Breeding Mechanic
Regular spiders spawn naturally in the world, not through breeding.
Unlike cows, sheep, or horses, they do not accept food items and do not produce baby spiders.
Cave Spiders Cannot Be Bred Either
A cave spider is a smaller spider variant, and it also cannot be bred.
Even though it acts a lot like a normal spider, it still has no breeding option.
Why Players Confuse Spawning With Breeding
Spiders often appear in groups, especially near dark areas or spawners, so it can look like breeding.
Both spider types are hostile mobs, and their numbers come from game spawning rules, not from player breeding.
How Spiders Actually Appear In A World

Spiders appear in a few specific ways, depending on where you are and what setups exist nearby.
If you want more spiders, focus on darkness, spawners, and special structures instead of breeding.
Natural Spawning Conditions For Spiders
In the Overworld, spiders can spawn in dark areas when the light level is low enough.
They appear in suitable open spaces, which is why caves and unlit areas often fill with them.
Monster Spawner Locations And Uses
A monster spawner can create spiders in certain rooms, especially in dungeons and mineshafts.
Players use these blocks for farms because they keep generating mobs as long as the area stays active.
Trial Spawner Encounters In Trial Chambers
A trial spawner in a trial chamber can also produce combat encounters tied to the structure.
These are event-based mob sources that spawn hostile mobs during exploration.
What Makes Cave Spiders Different

Cave spiders are smaller and faster, able to fit through tight spots.
Their attack effects also make them feel very different from regular spiders, especially in cramped spaces.
Smaller Size And Tight-Space Danger
A cave spider is easier to miss because of its size, and it can slip through openings that regular spiders cannot.
That makes abandoned mineshafts and narrow tunnels extra risky when you explore.
Poison Effect On Higher Difficulties
Cave spiders can apply a poison effect when they hit you, except on Easy difficulty.
That poison damage can add up fast if you get trapped in a small room.
Drops Such As Spider Eye
Cave spiders can drop string and sometimes a spider eye.
The eye is useful in brewing and some crafting paths, so players build cave spider farms for drops, not breeding.
What To Breed Instead If You Need Mob Resources

If you want resources, choose mobs that actually support breeding.
Many animals give steady drops, and some special cases use unusual items.
How Animal Breeding And Breeding Cooldown Work
Most breedable mobs enter love mode when you feed them the right item.
After producing a baby, they enter a breeding cooldown that keeps farms from growing too fast.
Horse Breeding And Other Breedable Mounts
Horse breeding is useful if you want better mounts.
It also works with donkeys and mules in certain combinations.
Llamas, camels, and other breedable animals can also fit into stable farm setups.
Unusual Breeding Items Like Bucket Of Tropical Fish And Torchflower Seeds
Some breeding items are less obvious. Axolotls need a bucket of tropical fish.
Chickens and sniffers use torchflower seeds. Armadillos breed with a spider eye, which makes it a useful item to keep on hand.
Players still cannot breed spiders.