How to Build an Automatic Wool Farm

Wool is the material you burn through fastest and gather slowest. Three for a bed, six for a banner, two wool for three carpet, and hundreds the moment you start decorating. A single sheep standing on a grass block with a dispenser pointed at its face will shear itself forever without you touching it. Sixteen of those side by side gives you every colour in the game on tap, and you never spend another dye.

The loop, and why it closes

An adult sheep regrows wool by eating grass, and by nothing else. No wheat, no time passing, no shelter — it has to eat. That single rule is what makes the farm possible.

1. 1.The dispenser shears the sheep. Wool drops at its feet and the sheep is left bare.
2. 2.Sooner or later the sheep lowers its head and eats the grass block it is standing on. Sheep do this on their own random schedule, woolly or bare — being sheared does not make one seek grass out any faster, it just means the meal has something to give back.
3. 3.On that exact tick two things happen: the grass block becomes a dirt block, and the sheep's wool grows back.
4. 4.An observer watching that block sees grass turn to dirt and sends out a pulse.
5. 5.The pulse fires the dispenser. Back to step one.

The trick is in steps three and four. An observer cannot see the sheep — observers only detect changes in the block directly in front of their face, never entities. But the sheep leaves a block change behind every time it feeds, and that change lands on the same tick as the wool. Watching the floor is watching the sheep.

That is also why you should not run the dispenser off a clock. A clock hammers away at whatever interval you chose, mostly at a sheep that has nothing to give, and it never stops running. The observer fires once per fleece, needs no tuning, cannot desync, and sits completely idle while the sheep is bare.

Parts for one module

• One adult sheep. Lambs cannot be sheared at all.
• Grass blocks — one for the sheep to stand on, plus as many living neighbours as you can give it.
• One dispenser and one pair of shears, ideally with Unbreaking III.
• One observer, one solid block, one redstone dust.
• One rail, one minecart with hopper, one hopper, one chest.
• Fences or glass for the pen walls. Not stone, and the reason matters.

Building it

1. 1.Dig the collection shaft. Pick the block your sheep will stand on and mine out that block plus the three beneath it, leaving a 1x1 shaft four deep.
2. 2.Chest at the bottom, then a hopper on top of it, crouch-placed so it feeds down into the chest.
3. 3.Rail on top of the hopper, and a minecart with hopper parked on the rail. It never moves. The hopper underneath drains it into the chest continuously.
4. 4.Put the floor back. A grass block goes directly above the rail. Mining grass without Silk Touch gives you dirt, so either bring a Silk Touch tool, or place plain dirt outdoors and wait for the surrounding grass to spread onto it.
5. 5.Dispenser. One block out from the sheep's square, at the same height as the sheep's feet, facing straight into that square. A dispenser shears whatever is in the block directly in front of it, so the sheep must never be able to stand anywhere else — cap the dispenser with a solid block or a fence post, because a sheep clears a one-block jump from standing and a lone dispenser block is a step out of the pen.
6. 6.Observer. Directly underneath the dispenser, level with the grass block, face pointed sideways into the grass block.
7. 7.Power it. Put a solid block against the observer's output end (the flat back, opposite the face), then one redstone dust on top of that block. The dust ends up level with and beside the dispenser, so every pulse fires it.
8. 8.Fence the pen. Ring the remaining three sides of the sheep's square with fence, so the pen is exactly one block of standing room with the dispenser as the fourth wall.
9. 9.Load and stock. Shears into the dispenser, sheep into the pen — lure it in with wheat or walk it in on a lead — and seal the last fence behind it.

Shear the sheep once by hand to start the cycle. From there it feeds itself.

Keeping the grass alive

This is where nearly every dead wool farm dies. Once the sheep eats, you are left with a dirt block, and if that dirt never turns green again the sheep never eats again and the farm produces nothing for the rest of time.

Grass spreads from a living grass block to nearby dirt, but only under conditions: the source grass block needs a light level of at least 9 above it, the dirt needs at least 4, and whatever sits directly on top of the dirt must not block light. Outdoors under open sky all of that is free. Build it indoors or underground and you need real lighting nearby — see base lighting and mob-proofing for the levels.

That is exactly why the pen walls are fences or glass rather than cobblestone. A grass block with a solid block sitting on top of it goes dark and reverts to dirt. Ring your pen in stone and you quietly kill the ring of grass that was supposed to reseed the floor. Fence posts and glass let light straight through, so the neighbours stay green.

Two more things that kill the regrowth:

• Not enough neighbours. Spread is a random-tick roll made by each living source block, and it only reaches a block away, so a floor with eight green neighbours recovers far faster than one with a single neighbour. Make the whole surrounding area grass.
• The wrong floor. Sheep eat grass blocks and short grass. They will not touch dirt, coarse dirt, podzol, mycelium or moss. A pen floored in anything but grass produces exactly one fleece, ever.

Shears, durability and restocking

Every successful cut costs a point of shear durability, and a pair of shears does not last long enough to forget about. Unbreaking III is the fix — on tools each use only has a chance to spend durability, so level three works out at roughly four times as many cuts on average.

Mending is a trap here. Nothing inside a dispenser collects experience, so a Mending pair simply never repairs itself and you have wasted the enchantment; see the anvil and Mending guide for where it actually pays off.

For a farm you leave running, feed the dispenser from a small chest through a hopper full of spare shears. Keep that chest pure — a dispenser fires from a random occupied slot, so one stray stack of cobble in the supply line means the dispenser periodically flings cobble at your sheep instead of shearing it. Hopper mechanics covers locking a supply line down properly.

Why the collection uses a minecart

The wool lands on top of the grass block, in the same block space the sheep occupies. An ordinary hopper cannot reach it: hoppers only pull items out of the block directly above themselves, and the block above your hopper is solid floor.

A minecart with hopper parked on a rail below the floor picks items up through the block above it. It is the same trick crop farms use to collect from underneath a field, and it is the reason nearly every wool farm has a cart buried under each pen. The hopper beneath the rail then drains the cart into your chest.

Do not skip it. Dropped items despawn after five minutes, so a farm with no collection is a farm that produces nothing you can ever pick up.

Colouring the sheep

Use dye on a sheep and the change is permanent. Every fleece it regrows from then on comes back in that colour, forever, for the cost of one dye.

Compare that to dyeing the blocks: one dye per wool block in the crafting grid, every single time. A dyed sheep has paid for itself by its second shear and is pure profit after that. This is the entire argument for a sheep wall over a dye chest.

Practical notes:

• Dye each sheep while it still has a full coat, before it ever goes near a dispenser. A sheared sheep refuses dye outright, so a sheep you forgot about is stuck on its old colour until it eats again.
• Naturally spawned sheep are overwhelmingly white, with grey, light grey, black and brown showing up occasionally and pink being genuinely rare. Do not dye the whites unless you need the colour — white wool is the base for everything.
• Dye sources are mostly flowers, plus bone meal for white, lapis lazuli for blue, ink sacs for black, cocoa beans for brown, and smelted cactus for green.
• Breeding mixes colours. Feed two sheep wheat and the lamb usually inherits one parent's colour, but if the two parents' colours are a pair you could actually combine on a crafting grid the lamb comes out the mixed colour — a blue and a red sheep can give you a purple lamb. Green is the exception worth knowing: it has no crafting recipe at all in Java, so no pair of differently coloured sheep will ever breed you a green one. Breeding and taming covers the mechanics.

Do the breeding in a separate pen. A lamb in a shearing cell is an unshearable occupant blocking a slot until it grows up.

Scaling to a sixteen-colour wall

Build one module, watch it complete two full cycles on its own, and only then copy it. Debugging one pen is easy; debugging sixteen identical broken pens is not.

• Lay the cells out with fence walls between them. A cell, a fence line, a cell, a fence line. Sixteen cells four by four comes to a 7x7 block of pens and fence lines — but that only counts the pens. Every module also needs its dispenser, and behind that the observer, the power block and the dust, none of which fit inside a one-block divider. Leave a service lane behind each row and budget noticeably more ground than the bare 7x7.
• Keep the whole surface as grass. Fences do not block light or interrupt grass spread, so a continuous grass field under the entire structure means every pen has plenty of live neighbours reseeding it.
• One cart, one hopper, one chest per cell. Sixteen small chests keeps the colours perfectly separated with no sorter to build and nothing to desync. Only merge cells onto a shared line if you genuinely want mixed output.
• Keep each module's redstone isolated. A dust that reaches two dispensers will fire a neighbouring pen on the wrong schedule. One observer, one dust, one dispenser.
• Light it or leave it open to the sky. A roofed pen goes dark, the grass dies, and the whole wall stalls at once.
• Build it where you actually spend time. None of this runs in an unloaded chunk, so put it at your base or next to wherever you idle.

What to expect from it

Each cut yields one to three wool, and an adult sheep only gets round to eating every so often — expect a minute or two between meals per sheep on average, longer while the grass is still growing back. One module is a slow trickle. Sixteen is a steady background supply that keeps every colour stocked without you ever walking into a field with shears again.

For bulk white wool it is still faster to convert string, since four string crafts into one wool and a mob grinder produces string by the stack. The point of a sheep wall is not volume — it is having magenta, cyan and light blue on demand at zero ongoing dye cost. Once the chests start filling, run the colours through the banner designer and put them to work.