I assume the answer is "OMG I can't believe you haven't mulched yet!?!" But just in case there is more to the issue than this novice gardener guesses, do you mulch? and if so, with what? I am in SF, CA with 2 4x4 raised beds and some container plantings and am wondering what kind of mulch is recommended as well as how much and...why? Holds the moisture in? Because I'm actually a crazy person that loves weeding... Can I just smack some grass clippings on top of my beds? Is there any veggie you shouldn't mulch?