Desert valleys
UC climate zone BImperial and Coachella valleys · UC groups the high and low deserts with the inland valleys, and that grouping shows up in the season: heat is the hard edge, not cold.
- Set plants out
- December – March
- Start seeds indoors
- November – February
- What ends the season
- Heat, not frost. A plant set out in December or January is finishing as the 100°F days arrive, and flowering shuts down for the summer.
Summer heat ends this crop early
UC's temperature table puts flowering out of business at 100°F, and the Imperial and Coachella valleys reach that most years from June through September. A crop planted late is still flowering when those weeks arrive, and flowering stops.
Plant to finish, not to start: work back from your hottest weeks. Count the variety's days to maturity from the planting date, not from your first frost date, which is not the constraint here.
Places in this window: El Centro · Brawley · Indio · Coachella · Palm Springs · Blythe
Also start here: The high desert around Joshua Tree and Twentynine Palms runs cooler than the valley floor. Start from the desert dates, then track your own night temperatures instead of the calendar on the floor of the valley.



