The photograph below appears in the the book, City of San Diego and San Diego County:
The Birthplace of California, by Clarence Alan McGrew, published in 1922:

McGrew was not kidding whan he referred to the Escondido Valley as both “beautiful and productive.” Below see a clip from the Escondido Times-Advocate from the same time period, September 23, 1924:

I remind my readers that the reference in the article to “carloads” refers to railroad cars full of produce. And note among the destinations that the grapes, grape juice and tomatoes were being shipped to were Pueblo, Colorado, Chicago, Illinois and Newark, New Jersey.
And it wasn’t just the Escondido area shipping its farm products across the country. I can show you similar newspaper and local government reports of communities throughout the county shipping all manor of crops. Over one hundred years ago, San Diego was feeding itself and the nation. You can find out more by attending my lecture, “Eating Local in the Roaring Twenties,” this Friday at 10 a.m. at Oasis in Grossmont Center. To find out more including how to register, visit https://san-diego.oasisnet.org/catalog/ .