Here is my fully automatic sugar cane farm. It uses an RFtools sensor to tell when the sugar cane is 3 blocks tall, then it pushes the blocks out behind the sugar
Farming Sugar Cane - Minecraft 101
How to create an automatic sugarcane farm in Minecraft
EASY AUTO SUGARCANE FARM! | The Minecraft Guide - Tutorial Lets Play (Ep. 25) - YouTube
How to make an automatic sugar cane farm in Minecraft - Gamepur
Sugar Rush! How to Make an Automatic Sugarcane Farm in Minecraft « Minecraft :: WonderHowTo
Minecraft - AUTOMATIC SUGARCANE FARM [ Redstone Tutorial ] MCPE / Xbox /... | Minecraft, Tutorial, Xbox
Sugarcane Farm - Blueprints for MineCraft Houses, Castles, Towers, and more | GrabCraft