Cardboard boxes by truck or rail, refrigerated containers
The ground
by boat
Lettuce and tomatoes
70%
Lettuce can be grown in a garden almost anywhere in the US, but by far the majority of commercial lettuce is grown in the Salinas Valley on California's central coast.
Lettuce (iceberg) is grown in fields I believe from Arizona to California. In the Spring it comes from Arizona and as the ground warms up the harvest moves into Southern California, then into the Central Valley and then into the Coastal Valleys.
They are generally transported by land, rail or air
Citrus fruit, lettuce, strawberries, tomatoes.
California is the biggest producer of strawberries followed by Florida. California grows them from January through November.
There are many things that you in California's fall climate. My favorites include Onions, Garlic, Shallots, Cabbage, Brussel sprouts, Lettuce, kale,Baby green lettuce, carrots, celery, Artichoke, Potatoes in November. There is a lot more I suggest talking to your local nursery.
Some main crops would be lettuce or carrots. Produce is the main heart of product activity. 2/4 of the produce grown in America is grown in California.