How to build an automatic sugar cane farm in Minecraft

This farm harvests each plant when it reaches 3 blocks and keeps the base, so it replants itself forever. It loses no drops: we ran it on a Java Edition 26.3 server and every cane ended in the chest. The plan holds 8 plants, the most one water source can feed.

Orientation used below: the canes run in a straight line, the water is on their left, the pistons on their right. The chest sits one block past the last plant, at the level of the hoppers.

Dig a trench 3 blocks deep under the future row of canes: hoppers at the bottom, rails above them, dirt on top. Place a Chest at the far end, then 8 Hoppers in a row, each pointing into the next one and the last into the chest (layer 2 of the plan). Sneak while placing each hopper against the previous one so it points the right way.

1. Place a Rail on every hopper (layer 3). Each hopper takes items out of the minecart above it.
2. Put one Minecart with Hopper on each rail. Wall both ends of the rail so the minecarts cannot roll away.
3. Beside the last rail, under where the end of the water will be, place one more Hopper pointing down into a Hopper that points into the last hopper of the line.

1. Cover the rails with a row of 8 Dirt blocks (layer 4). Grass Block, Sand, Mud and Moss Block work as well.
2. Next to the dirt, dig a 1 block wide channel at the same height, with a solid floor except over the end hopper.
3. Pour one Water Bucket at the first block of the channel. Water flows 7 blocks, so it reaches the hopper at the end and carries floating items into it.
4. Build a wall 4 blocks high across both ends of the farm so no item flies out.

1. On the side opposite the water, 2 blocks above the dirt, place a Piston in front of each future cane, head toward the cane (layer 6). A piston's head points toward you when you place it, so stand on the dirt row and look at the spot.
2. Above each piston, place an Observer whose face looks at the spot of the third cane block (layer 7). Its face also points toward you when you place it, so do it from the dirt row too; the red dot ends up at the back.
3. Behind the observers, put a row of solid blocks one level lower and a line of Redstone Dust on them. Each observer powers the dust behind it, the dust powers the block under it, and that block pushes the piston.

The dust links every observer, so when one cane reaches 3 blocks, all 8 pistons fire. Canes that are 2 blocks tall lose their second block too: nothing is wasted, the base always stays.

Plant last. Wait until the water reaches the end of the channel, then plant one Sugar Cane on each dirt block (layer 5). A cane only survives with water next to the block under it: if you plant before the water arrives, it breaks.

The top block of a cane grows after 16 random ticks. With the default random tick speed of 3, a block of a chunk section gets one every 1,365 game ticks on average, so a new cane block appears about every 18 minutes: 3.3 canes per plant per hour, about 26 an hour for 8 plants. Crops only grow while you stay within simulation distance, so build the farm near your base.

The build uses no quasi-connectivity or other Java-only redstone. We tested it on Java Edition 26.3 only, including the minecart collection. In Bedrock Edition sugar cane also grows from Bone Meal, which Java does not allow.