This tutorial shows you how to make a semi-automatic sugarcane farm in Minecraft Pocket Edition (tested in 0.10 alpha). Total effective yield is 60 sugarcane (30 plants times 3 sugarcane, reusing 30 to plant the next batch). Harvesting requires the placement and removal of 1 Dirt block and then collecting all the sugarcane.
30 Sand blocks
14 Glass blocks (or any other solid block, such as stone, wood, wood planks, wood slabs etc.)
1 Bucket filled with water
At least 10 Dirt blocks, more if you decide to build the 3-high walls from step X
6 Stone (any type, e.g. Cobblestone) blocks
30 Sugarcane (but you can always start with less and have the farm generate the rest :) )
1 Spade (for ease of digging)
1 Pickaxe (to remove blocks accidentally placed in a wrong position)
90 Stone, Dirt, Glass or any other type of solid block to act as a "splash protection fence" as per step 13
Step 1: Dig a Trench
To begin, find or create a flat area 5 blocks wide and 17 blocks long. Leaving a 1 block border all around, dig out a 1-block deep trench measuring 3x15 blocks.
Step 2: Place Sand
Place 2 rows of Sand blocks, one on each side of the trench, leaving a single channel in the middle. This is where you will place the Sugarcane once the farm is complete.
Step 3: Scaffolding for the Water Supply
Using the Dirt blocks, build a 4 step staircase next to the sand, in such a way that the tallest step is at the 8th block of Sand in either direction. This staircase will be used as scaffolding while building the water supply.
Step 4: The Water Supply
Place a block of Dirt on top of the tallest step of the Scaffolding, then attach a block of Cobblestone sideways so it hangs over the first row of Sand. Attach another block of Dirt to this Cobblestone block, then place Cobblestone against all sides. Remove the 2 blocks of Dirt you just placed (the Cobblestone blocks should now be a floating cross 5 high above the Sand and the trench.
Step 5: The Water Supply Part 2
Add 2 more pieces of Cobblestone below the cross, directly above the trench (So not above the sand). You will use these Cobblestone pieces as anchor pieces for the Dirt block that will control the harvesting cycle.
Step 6: Add Water
Climb the staircase and place a Water source block using your bucket in the center of the Water supply cross. Make sure this source sits on the top layer (between the 4 Cobblestone pieces) and not on the layer below it (with the two Cobblestone pieces) otherwise the water source block disappears as soon as you start operating the harvesting cycle. The water should now flow down and sideways and fill the entire trench.
Step 7: Cover the Trench
Right at each end side of the water-filled trench, place a Dirt block, and then place Glass blocks against it to cover the trench, leaving only the center block open where the water column enters the trench.
Step 8: Overflow Area
Now remove the Dirt block you place when placing the Glass blocks (on each end of the trench) and dig one block down to create an overflow area. This area will be useful once harvesting, as it will catch any blocks and sugarcane landing in the water.
Step 9: Planting Time!
Now you can go ahead and plant your Sugarcane. Keep 2 things in mind:
1. Do not leave any gaps between the Sugarcane plants, or the harvesting will not work on all plants.
2. If you do not have enough Sugarcane to cover all 15 Sand blocks on one side, make sure you have at least planted on the Sand blocks directly next to the water source.
Step 10: Some Cleanup
It will take a while for the Sugarcane to grow, but it will grow in light and dark places (even underground!). Let's use the time to do some cleanup. For easier access to the harvesting steps, remove one step layer from the Dirt scaffolding we built earlier (or turn it into a nice wooden or stone staircase, if you so fancy). You can also add fencing and ornamental features to your design at this point, as long as they keep a 3 block space for the Sugarcane to grow.
Step 11: Harvesting Time!
Once your Sugarcane has grown sufficiently, it is time to harvest. Take a Dirt block in your hands and climb up the stairs. Insert the Dirt block into the water stream between the two Cobblestone blocks. The water should now stop running - wait for it to dry out completely from the trench. If Minecraft glitches and leaves some puddles, go down and remove them by digging out the block underneath it and then filling the hole.
Step 12: Harvesting Time Continued
Now remove the Dirt block you just placed in the water stream. As the water stream falls down, all the Sugarcane will POP and scatter, ready for collecting! If all the Sugarcane grew to full height (3 blocks high), this results in almost one-and-a-half stack of Sugarcane, of which you need 30 to replant for the next harvesting cycle. Rinse and repeat!
Don't forget to check the overflow areas at each end of the trench, as occasionally some Sugarcane might collect there.
Step 13: Optional: Retaining Wall
You might notice that high growing Sugarcane tends to scatter over a wider area when harvested. If you want to, you can enclose the Sugarcane farm in a 3 block high wall. This will help contain the Sugarcane so that you can collect it by just walking a U over the two Sand layers.
Step 14: Doubling the Size
You can put 2 Sugarcane farms next to eachother and connect the water sources to create a double-sized farm. Place the water source block in the middle between the two farms the same way you built the water source earlier (just a little higher up) and you can control the harvesting cycle centrally the same way as before, by placing and removing just one Dirt block ... See the picture for inspiration on how to do this. This way one harvest yields 180 Sugarcane, of which 60 is needed for the next planting cycle, leaving 120 Sugarcane for your recipes!