I did a search on Google Books looking for ["salad bowl" immigration] and doing some date filtering to find the earliest reference to this.

The very earliest I can find is this:
http://books.google.com/books?id=0oEDAAAAYAAJ&dq=salad%20bowl%20immigration&pg=PA535#v=onepage&q=salad%20bowl%20immigration&f=false

That’s a 1914 article that talks about a social event where there was an “Immigration Salad” game that was played as part of a program topic on the “Melting Pot.” Interesting, but it was more about helping people at the event learn more about each other than a metaphor for immigration.

After that, I found this 1961 essay by Franklin D. Scott, as part of a collection of essays. It’s called “Immigration And American History” and has this reference:

“The process of amalgamation maybe should instead be called the salad bowl. For a piece of lettuce, even after soaking in French dressing, is still a piece of lettuce”

If I’d left it just to Google Books, this is what I would have thought was the first print reference to the term and likely the origin.

However, the collection of essays was edited by Henry Steele Commager. I originally thought he was the author of that particular essay, so I did another search for [henry steele commager salad bowl], which lead me to this interesting article:

The Myth of Americanization or the Divided Heart: U.S. Immigration in Literature and Historical Data, 1890-2008
http://ejas.revues.org/8935

That had this reference:

“Students considered immigration in the light of the “Melting Pot” and were taught that all immigrants would, within reason, meld into one composite “American” whole. Later, we learned that newer emigrants might not lose or relinquish all of their own identity and so we considered historian Carl Degler’s formulation of the “Salad Bowl Thesis” as a more appropriate metaphor to describe how immigrants would retain their fundamental identity with a covering of unique American salad dressing that made us all Americans.”

In a search for Carl Degler, to find out if he might have originated this, I came across a page about him with this quote:

http://thinkexist.com/quotes/carl_n._degler/

“The metaphor of the melting pot is unfortunate and misleading. A more accurate analogy would be a salad bowl, for, though the salad is an entity, the lettuce can still be distinguished from the chicory, the tomatoes from the cabbage.”

To have a quote like that suggested he was especially well known with this concept.

Going back to that article I mentioned, I also see that here:

Carl N. Degler wrote in his widely-used college history textbook published in 1970 that “the metaphor of the melting pot is unfortunate and misleading. A more accurate analogy would be a salad bowl,” Degler wrote, “for, though the salad is an entity, the lettuce can still be distinguished from the chicory, the tomatoes from the cabbage.”

That gave me the impression that Scott first conceived, or at least wrote about, the metaphor, then Degler helped popularize it through his textbook, “Out of Our Past: The Forces that Shaped Modern America.”

You can find his quote here as part of that (though it’s the 1984 edition that’s in Google Books):

http://books.google.com/books?id=KSCMXKButowC&lpg=PA322&dq=Out%20of%20Our%20Past%3A%20The%20Forces%20that%20Shaped%20Modern%20America%20salad%20bowl&pg=PA322#v=onepage&q=salad%20bowl&f=false

Still, there was something bugging me. That journal article said his textbook was published in 1970 — so well after Scott’s 1961 reference. But the footnote to the reference said this:

“Out of Our Past: The Forces that Shaped Modern America. 1957 (article), book (1970)”

Had Degler written an article on the topic that later expanded into the textbook?

That led me to search for [Out of Our Past: The Forces that Shaped Modern America 1957], where listings for Degler’s page on Wikipedia and at LibraryThing:

http://www.librarything.com/work/224490
http://en.wikipedia.org/wiki/Carl_Neumann_Degler

Suggested this was a 1959 book. Now, I’d been at Degler’s page earlier on Wikipedia. It gives him no credit for the salad bowl term there, so you’d easily miss this (something that will no doubt change soon).

So back to Google Books. Why didn’t Google help me spot this earlier reference? Well, Google’s pretty lame, at times.

As I mentioned, where I found his quote before was from the 1984 edition, and if you look at the cover here:

http://books.google.com/books?id=KSCMXKButowC&printsec=frontcover&dq=Out+of+our+past:+the+forces+that+shaped+modern+America&hl=en&ei=_KtqTvLjDM_KiAKizu24Dg&sa=X&oi=book_result&ct=result&resnum=1&ved=0CCoQ6AEwAA#v=onepage&q&f=false

Google doesn’t suggest there’s another version. However, if you dig into the About This Book page:

http://books.google.com/books?id=KSCMXKButowC&dq=Out+of+our+past:+the+forces+that+shaped+modern+America&source=gbs_navlinks_s

At the bottom is an “Other Editions” section that leads to this list:
http://books.google.com/books?q=editions:ISBN0061319856&id=KSCMXKButowC

There, you can see the 1959 edition is listed — along with a 1952 edition! Maybe that one’s some type of cataloging error.

Anyway, Google clearly knows that there’s a “salad bowl” mention in the 1959 book, as you can see here:

http://books.google.com/books?id=fIFp9z-aF-oC&dq=editions%3AISBN0061319856&q=salad+bowl#search_anchor

Though it doesn’t find the exact spot. If you go back to the original quote, however, he only says “salad” and not “salad bowl.”

Try as I might, I can’t get Google to display the exact quote from the book — searches for words in that quote like “lettuce” or “chicory” yield nothing. There’s probably some backend problem with Google causing this.

If you made it this far, some bonus links.

Here’s The Nation reviewing Degler’s 1959 book and mentioning the salad bowl concept:

http://books.google.com/books?ei=Ga1qTqvLCcPliAKD7emqDg&ct=result&id=Xy8QAAAAIAAJ&dq=salad+bowl+degler&q=salad+bowl+#search_anchor

Here’s a fairly modern teacher’s guide with the concept:

http://books.google.com/books?id=keeIVNQw_GIC&lpg=PT1039&dq=salad%20bowl%20immigration&pg=PT1039#v=onepage&q&f=false

It also talks about the “stew pot theory” which is between the melting pot and the salad bowl.

Sincerely,
Dr. Bryan K. Hickman the multiculturalist

Every democracy has fallen by itself. Multicuturalism does nothing but splinter the people of a single nation. It does NOT promote progress, rather it impedes it.

The biggest lie told about the Melting Pot is that it requires a full relinquishing of your ethnic/cultural past. Without this lie, the shortsighted Salad Bowl concept would have a leg to stand on. It had to pervert the idea of the Melting Pot in order to claim its superiority.

okay… i’m confused, so what to do? not or preserve your culture? being multiculturalist? pluralist? ah well… whichever… its just a perception.

anyway, god create humans in tribes, nations (more specifically, diff color of skin, hair, height, etc)for just to know each other, you don’t need to know each other if people is exact same copy of you.

One of the things that makes America a great country is that people can choose whatever bits of culture they want to. I eat Indian food, have furniture made in Sweden, and posters on my walls written in Japanese. People shouldn’t feel the need to adhere to the dictates of their own cultural background, and the multiculturalists who want to pigeonhole people by their ethnicities are doing the world a great disservice.

I’m Irish-American but I don’t feel the need to wear green and drink beer all the time, but the multiculturalists seem to think it’s fine for people of Chinese or Korean or whatever backgrounds to isolate themselves by their ethnicities.