Though the San Francisco Bay Area is not traditionally known as an orange-growing hub, some varieties will do well in a home garden. This region, which is defined as USDA Hardiness Zone 9, has many microclimates. Oranges that may grow well in the warmer inland areas will likely not fare as well on the coast. Oranges require heat to produce sugar, and the varieties that thrive in Northern California are generally those that have low heat requirements.
This sweet orange is known for its ruby-red flesh and raspberry flavor. These orange trees, which grow to about 25 feet, need a minimum amount of heat to produce sugar. Most fare well in the Bay Area's inland region, although the "Moro" cultivar can succeed closer to the coast.
These small, loose-skinned, juicy oranges are easy to peel and make good eating oranges. Mandarin trees, which grow to about 15 feet, are both cold hardy and drought tolerant, making them a good selection anywhere in the Bay Area. Mandarins also require only moderate heat to produce sugars.
The sweet "Clementine," rich "Fremont" and mild "Pixie" cultivars are all good Bay Area selections.
Sweet oranges may produce enough sugar to produce tasty fruits even where summers are not warm. Sweet oranges will be sweeter the farther inland you are in the Bay Area, but they are a good choice for anywhere other than right on the coast. Trees that produce sweet oranges usually grow to about 25 feet and produce a traditional, round, baseball-sized fruit. The rose-fleshed "Cara Cara" and juicy "Trovita" are good Bay Area selections.