Farming sugar cane is quite easy, though the requirements of sugar cane to grow can make it a bit tricky to increase our land use efficiency. However, there are a few ways with which you can plant as many sugar cane in small plots of land as possible.
There are 2 things we have to keep in mind. The first is that sugar cane can only grow on sand, dirt or grass blocks directly next to a water block, diagonally doesn’t count. Secondly, for sugar cane to grow up to 3 blocks high, no other blocks can be placed up to 4 blocks above the ground. Sugar cane will never grow against the bottom of a block.
Taking this into account there are a few builds you can make. The first one is shown below, which uses as little water blocks as possible, while still creating a square shape. This size is as small as you can go, other sizes will have empty spots.
However, this size is also the only size which you can use to create bigger versions, which will always be a few of these squares next to each other. So a 6×6 square isn’t really possible, but an 8×8 square is, as you just place 4 of the 4×4 squares next to each other.
This method gives us a land use efficiency of 75%, but we can do better than that, a lot better. While the following method isn’t the most harvest friendly method, it is the most land efficient method out there. So if you’re short on space, for example when you’re doing a custom challenge or when you’re using a plugin like Towny, this setup can be perfect to maximize the amount of sugar cane you can farm on small plots of land.
As you can see in the image above, we managed to grow 8 sugar canes on a 3×3 plot by simply dropping water from a higher spot. Note that the water flows under the 4 elevated grass blocks to make sure the lower sugar canes also get some water.
It’s perfectly fine to lower 2 of those blocks opposite to each other, so only 2 blocks are elevated. This allows for easier harvestable rows of sugar cane to be created, as you won’t have to jump every 2 blocks. Instead you can just walk forward and punch everything.
It’s incredibily easy to create a (semi-)automatic sugar cane farm. All you need is a row of pistons and a row of sugar cane.
As you can see in the image above, pistons are placed 1 block above the base of our sugar cane. Whenever we feel like harvesting our sugar cane, we simply pull the lever and it’ll pop out all the sugar canes above the 1 block base. Most of the sugar canes will drop into the water, which will carry it with the current to whatever collection spot you want.
Some sugar cane will drop onto the sugar cane base, which is perfect because we can then simply push it off again with our pistons. This way all sugar cane will fall into the water, with the exception of perhaps 1 or 2 every now and then who manage to fall on the edge of the grass blocks.
To make your farm fully automatic, all you have to do is add a timer between each input. You could do this with redstone clocks. One effective clock would be a despawn clock, which uses the 5 minute despawn time of blocks with wooden pressure plates, to send a signal once every 5 minutes, by simply adding a signal inverter between the pressure plate and whatever it has to be connected to.