In contract law is small wordings important in the sense of getting out on technicalities important? For example a lease for a rental property may state "the premises may not be used for manufacturing drugs or other controlled substances". Could someone growing marijuana successfully argue that marijuana may be a drug but they weren't manufacturing it; they were growing it? I red in the question about gag orders and warrant canaries, these sorts of tricks don't really work.
Growing marijuana is very often legally classed as "manufacture of a controlled substance." In criminal law, "manufacture" tends to be explicitly defined to include cultivation, but this is in fact a reasonably common use of the term (it doesn't have to mean producing with machinery). And so it's extremely unlikely that anyone will be convinced that you even might have thought the agreement didn't cover growing marijuana. The intent of the parties is fairly clear there.
In general a contract is a shared understanding of an agreement between the parties - the words on paper are only necessary as evidence of what that understanding is.
If someone can convince a court that any word made a difference to how you understood the contract, then that could affect the ruling.
In this example I agree with cpast that a court would be unlikely to believe that 'manufacturing' was understood in a way that excludes growing plants.