There are several systems devised to decide what is appropriate to plant, where. The Species Index has several climate zones for each species. However, due to the fact that it is the most informative and nuanced, we chosen Sunset climate zones as the key way to determine what is appropriate for your foodscape’s climate context.
Sunset climate zones take into account:
Continental air influence. The North American continent generates its own weather, which ― compared with coastal climates ― is colder in winter, hotter in summer, and more likely to get precipitation any time of year. The farther inland you live, the stronger this continental influence. Wind also becomes a major factor in open interior climates.
Mountains, hills, and valleys. In the West, the Coast Ranges take some marine influence out of the air that passes eastward over them. The Sierra-Cascades and Southern California’s interior mountains further weaken marine influence. From the Rocky Mountains to the Appalachians, continental and arctic air dominate, with moist air from the Gulf pushing north during the warm season. During winter, Arctic outbreaks are most intense between the Rockies and the Appalachians. Both ranges act as barriers that limit the influence of the cold beyond them.
Microclimates. Local terrain can sharply modify the climate within any zone. South-facing slopes get more solar heat than flat land and north-facing slopes. Slope also affects airflow: warm air rises, cold air sinks. Because hillsides are never as cold in winter as the hilltops above them or the ground below them, they’re called thermal belts. Lowland areas into which cold air flows are called cold-air basins. Microclimates also exist within every garden. All else being equal, garden beds on the south side of an east-west wall, for example, will be much warmer than garden beds on the north side of the same wall.