It came with the major Cuban influx of the Mariel boatlift in 1980. Apparently street vendors were very common there, and they got things set up in So. Fla. the same way.

The vendors sell lots of stuff- nearly all of it things they buy cheap in bulk and then repack for retail. Like wilted flowers, and raw shrimp sitting in melted ice for hours, and bottled water, and peanuts in paper cones, and some kind of sausages... if you go down the main street there can be vendors waving stuff at you from every intersection.

I don't think I've ever seen any of them selling something they grew or made themselves.