If you have your heart set on growing vegetables but your yard doesn't get full sun for the entire day, there are a few vegetables that will grow in a partially shaded location. Vegetables grown in partial shade will grow more slowly than those grown in full sun, but they will produce a crop. Pamper them by watering them regularly, promptly removing weeds, and feeding them with both compost and a commercially prepared fertilizer.
Leaf lettuce (Lactuca sativa) is so named because it doesn't form heads. New leaves grow from the center of a central crown, forming a dense cluster of leaves that can be harvested individually as the plant grows. Because it is not putting all of its energy into growing a single large "head," leaf lettuce will grow in partial shade. Take advantage of this aspect of leaf lettuce and grow it during hot summer months. Hot weather usually causes lettuce to send up a seed stalk (called "bolting") and when that happens, the leaves turn bitter. If it is growing in the shade, even in hot weather, it will delay sending up a seed stalk, thereby delaying when it will turn bitter. Meanwhile, you can harvest its leaves for summer salads.
The best type of onion to grow in partial shade is the green onion (Allium fistulosum). Bulb onions will not form large bulbs if grown in partial shade and you'll end up with bulb onions the size of green onions. Plant green onions in early spring as soon as the soil can be worked. Small, pencil-size green onions will be ready to pick in about 65 to 70 days; as the season progresses they will increase in diameter.
Cool-weather-loving vegetables, radishes (raphanus sativus) are ideal to grow in shaded areas of the garden during hot summer months. Like leaf lettuce, they send up a seed stalk when hot weather arrives, but their taste becomes hotter afterward, while leaf lettuce turns bitter. Growing them in the shade will delay them turning hot. Radishes are fast-growing; with most varieties maturing in as little as 28 days. Plant radish seeds in the shade of larger crops such as corn, tomatoes, pole beans and peppers.
Technically a herb but widely grown in vegetable gardens, parsley (Petroselinum crispum) is another culinary plant that will grow quite well in partial shade. Parsley is a biennial, which means that it grows a rosette of foliage the first season, dies down to its roots over winter and bears flowers and seeds the following year. Pick the outer stems of parsley first, leaving the inner ones to grow larger and provide energy so the plant will continue producing leaves.