The local stores' selection and quality of good green vegetables is pretty limited. When I travel to the city I stock up on bok choi, napa, ba tai, brussel sprouts, cilantro, etc. Some wilts or yellows quickly, others last fairly well - sometimes for a couple weeks. The same vegetable that lasts well one time might wilt and yellow in a couple days the next time. Any suggestions on how to keep the greens green??