Why does The Dude say "the toilet seat's up" instead of "all my plants are dead"...

Reading the script for The Big Lebowski, it reads:

The Dude: You see a wedding ring? Does this place look like I'm fucking married? All my plants are dead!

But in the movie, The Dude states:

The toilet seat's up, man!

instead of:

All my plants are dead!

Was this improvised or a mistake in the script posted?

The line was probably changed to a funnier/clearer one. It isn't uncommon that scripts differ from actual movies, professional acting and directing not always require to follow every word of the script.