Rashi traded in wines and perhaps grew in his own vineyards as well. His profession and his location dictated an involvement in trade beyond his local environment. At his time there were significant Jewish communities in the area near him in Northeastern France and the entire Rhineland; in Spain; in Languedoc (Southwestern France) in the Ile de France (near Paris); in the city states that would become Italy; and points further accessible via the Mediterranean. There was also a very small number of Jews in what would become England, in places like London and York. Every one of these communities had merchants and traders. There was also a system of letters of credit within the communities that allowed for a remarkable flow of goods.
Rashi’s access to foods from these regions would only be inhibited by freshness and how well foods or spices kept over a long journey. So while citrus fruits for example wouldn’t be likely grown or eaten in the French/German borderlands where he lived, If they would keep long enough, he might occasionally get something of that nature from places like Lunel, or Narbonne, or Gerona. It would likely be harder to get these in the winter.
Later in Rashi’s life the chaos of the first crusade and the “people’s crusade” and the attendant attacks on Jews would have made access to any food more challenging. Certainly trade would have been curtailed.
The Champagne region where he lived part of his life grew a lot of root vegetables even before potatoes were introduced a few hundred years ago. turnips, carrots, etc were common. peas and lentils were too. There was more access to fish and poultry than to beef and lamb, and especially at that time, there was quite a bit of game such as deer in the forests of the Ardennes and the Aude. Apparently, though it wouldn’t impact Rashi’s diet, there was a great deal of wild boar and pigs, which WOULD have affected how much forest or grazing land was available for kosher animals.The area around Worms where he also lived had a bit less wild land and more settled farming land, so wheat and other grains woulds have been accessible as well. And both areas were and still are known for their cheeses, so there would have been access to some dairy products as well.
Another thing the area was known for, aside from wine, is beer, which means that barley grew in great abundance.
So, lightbrite, I hope that this helped. Another thing you might want to research yourself is to look into any agricultural terms Rashi may have used translated from Old French. He often did this, transliterating it into hebrew charachters and describing it as BLA’Z b’lashon am zu (in the colloquial language). There may be a concordance available of all of the hundreds of French words Rashi used in his commentary, but I am not aware of it. Anyone?