Gardening and growing some of your own food can be rewarding on several levels. The first one is practical. You are growing edibles that you know haven't been doused with anything that might be harmful to health. Most of the time the gardener can solve pest and blight problems through the use of household remedies and removal of problem plants before they ruin a crop. It takes attention, but when you consider the cost of organically grown, unaltered crops it is worth it. A small raised box of 4 feet by 8 feet can easily produce a pound a week of mixed greens among other vegetables. Tomatoes and peppers take a little longer, but ever-bearing fruits will keep going if harvested on a consistent basis.
Another reason for having a city garden is aesthetic. Growing flowers in the garden can provide one with fresh flowers for the home. Roses, zinnias and marigolds will bloom prolifically if tended to properly. Adding flowers to your home brightens up a room. The garden can also be a great place to relax or meditate in. Urban living can be stressful and a small spot in the backyard or on a roof or balcony can work wonders to help recover from the stress of working and living in a city.
As more and more people become aware of issues of urban sustainability, gardens are getting more attention. Rain Gardens can be planted to help control water runoff during storms. Runoff can overwhelm sewer systems and lead to more pollution and problems in coastal areas. Green roofs can help in the control of temperature in buildings and lower energy cost. The roofs can be either just grasses or combined with food production. Cities like Yonkers, NY have started planting on barges in the Hudson River. The South Bronx has a wonderful garden (La Finca del Sur) in between the Major Deegan Expressway and the Bruckner Expressway, an oasis in the middle of a desolate urban area. As small as the output of urban gardens and community gardens can be, they are a first step in bringing food production closer or into urban areas. This can help to control costs of shipping and the use of fossil fuels and preservatives that are necessary for long distance food transport.
Urban gardening is a winning proposition for many reasons.