“And all at once, summer collapsed into fall,” wrote Oscar Wilde, and that feels especially true this year. This past week’s cooler temperatures have brought the threat of frost to some of the higher-elevation farms in our region. While farmers tailgate markets have been seeing the transition to autumn for the past several weeks, suddenly cooler-weather crops are taking center stage. Tomatoes, peppers, and eggplant are all still available, but in shorter supply. Here are a few things to start looking for instead.