Find or craft cactus blocks
Place cactus on sand or red sand only
Leave at least one empty block of space on all four sides
Stack cactus vertically if the space above is clear
Build a row of sand blocks with gaps for growth
Place water nearby if you want to move items with a collection system
Use hoppers, minecarts with hoppers, or water streams to collect dropped cactus
Avoid placing any adjacent blocks next to cactus
Harvest cactus by breaking the top or middle block
Replant cactus by placing a cactus block on sand
Expand the farm by adding more sand rows and collection lines
Protect the farm from accidental block placement around cactus