Problem with cactuses

[zembol_pl]

Hi there,
today i started working on a cactus farm, but there seems to be some problem - cactuses wont break while touching fences...
I tried different fences, I tried putting the fances in a grid, but it didn't help.
I'm not a pro, don't know if its a version issue, server issue or my design is wrong.
I post a photo below.
I'd be glad if someone would tell me how to solve the problem (even an info that it can;t be solved is of help, I'd just remove the farm from my island).
See ya!

 

[Lqrenzo]

This design is fine. The cactus will break at a height of 3.
Well, maybe you have to build the roof a bit higher so that the cactus can grow higher.

 

[zembol_pl]

Thanks, I'll give it a try.

 

[zembol_pl]

@Lqrenzo it worked. Moved the celing one block higher and now it works just fine. Thank you for your help