A reader just wrote me asking for a farmstand recommendation. She just moved to Southampton, and has friends in Mattituck who insist that, as far as locally-grown produce goes, the north fork is where it's at. I'd love to help her out but I've shamefully only been to the Milk Pail in Water Mill and Sang Lee in Peconic, both of which were lovely, with excellent, if somewhat undersized bounty. So I'm turning her plea over to you. Where do you all get your 5-a-day fixings?