Keeping a vegetable garden weed free?

my boss owns a vegetable garden in which I'm supposed to take care of. First and foremost i am no gardener and i wish i was, But I'm willing to learn. It's my second summer here and on my first summer my boss called me a green thumb (That everything grew including weeds) . So my question is is there some kind of spray or anything that i can safely use to be able to grow my garden without any gr or weeds growing.