Arizona produces approximately 1/4 to 1/5 of the leafy greens grown in the US, by weight, depending on the exact commodity [1]. Meanwhile, California produces roughly 3/4 of such products grown in the US. The two states participate in a seasonal rotation, where California's temperate valleys produce most of the summer crop, and in the winter production is shifted to inland desert locales in both Arizona and California.

[1] https://cals.arizona.edu/arec/sites/cals.arizona.edu.arec/fi... [2] https://californiaagnet.com/2017/11/03/a-look-at-year-round-... [3] https://www.ers.usda.gov/webdocs/publications/93033/vgs-362.... [4] https://news.ycombinator.com/item?id=18535425#18536045