I am planning to build a raised garden bed. The purpose of the bed is to grow vegetables for my family of five. Ideally I'd like to grow tomatoes, peppers, zucchini, green beans and brussel sprouts, or just about anything that will taste great grilled. Perhaps also a section for cilantro. I am not sure how long to make the bed. I am planning for it to be 4' wide and about 28' long. Will this size garden give me an adequate yield of vegetables throughout our short growing season (zone 7 NJ), or should I build a longer garden bed? All advice appreciated. Thanks.