Put the summary of the bug you're having here

What I expected to happen was...:
Cactus will automatically break when grown.

What actually happened was...:
Cactus grew beside the block.

Steps to Reproduce:
1. Place a cactus on sand
2. Place a block diagonally from the cactus. (One space to one side of cactus and one space up)
3. Wait until cactus grows.