@Sudsrung0 I think that just the outright "NO SMOKING" might be more effective.
You don't want a bad guest to get cute and think that smoking a clove cigar (or worse) is still OK seeing as your sign is only specifically against tobacco and marijuana. . .
@Sudsrung0 I always laughed at the signs you see everywhere in Florida that say "No Shirt No Shoes No Service." It halfway implies that walking in bare-assed is totally fine, as long as you put the shirt and shoes on.
The specificity of your sign similarly suggests that maybe smoking crack or heroin or meth would be ok...