Gone to Seed
Many annual vegetable plants, especially greens will go to seed after their productive life-cycle is over. When this happens, the plant decides it is time to stop producing tasty food, and instead produce seeds so that it can carry on its genetics. The precursor to seeds is flowers; soon after the formation of flowers your plant will develop seeds. Unless you have a plant that is supposed to be eaten at this stage ( i.e. broccoli raab ) it is best to harvest your plant before it starts flowering. Before your plant flowers it will start to send up shoots or grow tall quickly, these stalks will elevate these flowers to make them easily accessible to the appropriate pollinators. Often, a sudden increase in temperature can cause your plants to flower, because they may think the season is ending. If you winter cropped greens, they will probably go to seed in the spring when the weather warms up. Annual herbs like cilantro, basil, and parsley will go to seed if they are not harvested in time.
You will notice that many plants look like broccoli when they flower, this is because these plants are a member of the genus brassica. You may not know brassicas by name, but they probably make up a big part of your diet. The following plants are memebrs of the brassica family: cabbage, mustard, canola, kale, broccoli, cauliflower, brussel sprouts, turnips and more.