(Live Science) The United States' major pumpkin states produce over one billion pounds worth of pumpkins annually. Immigrants to America couldn't find their usual produce to carve at Halloween, however, so they turned to a reasonable fascimile.“Gourds were scarce in the New World and turnips even scarcer, so pumpkins became the veggie of choice,” said Flieger.
Why We Carve Pumpkins, Not Turnips
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OCTOBER 29, 2009
Heather Whipps, Live Science

Big orange veggies are pretty strange as far as holiday symbols go, but there are actual historical reasons that we carve pumpkins every Halloween.
Read the story by Heather Whipps: www.msnbc.msn.com/id/33532948