If you're looking to make a herb with a vial of water, it can easily be done.
Not sure about adding garlics and stuff since it has an eat option, but just find a flawless powerbot stringer, change Id's of the longbow (u) to vial of water id, then change the id of bowstring's id into the herb's id.
If you get me id's for the herb and vial of water, and link me to a script, I can change it for you.