There are some things that are quintessentially summery. A tomato is one of them. We have beautiful Roma tomatoes in the shops at the moment - those are fresh plum tomatoes. In a few weeks there will be tomatoes of many shapes and colours available. Tomato salad will become an exciting and colourful meal.
I'm working in an old cookbook at the moment - a cheap one from the library. I couldn't bring myself to cover up the tomato when I did the background, and when it sat there on the page, the only thing I wanted to add was the word 'summer'. So I did. After all, it's my art journal and anything goes :)