If a garden is abandoned, would there still be food to harvest in its overgrown state the following year? Thank you!
Yes, in theory, there would be. There are several scenarios that would cause food in an abandoned garden to be available the following year. The first is volunteer plants. Tomatoes, squash and radishes can commonly do this - though in theory, any plant that was left to go to seed can do it, melons, peppers, carrots, etc). The food would not so much be left over from the previous year, but would grow from the seeds of the plants that were abandoned. Almost all gardeners in almost any zone end up with a few volunteer tomato plants the following year that, if left alone will grow and produce fruit. And we get questions all the time from people wanting us to ID squash plants that mysteriously pop up in their yard. They are almost always from a stray seed from a Halloween pumpkin the previous year, but sometimes it is a butternut or spaghetti squash.
Another scenario would be that some plants in the vegetable garden are perennials. Fruit trees and shrubs, strawberries, asparagus, rhubarb, horseradish and most herbs all fall under this heading.
Some plants can survive the winter as well, if it was mild. Almost all cole crops (cabbage, broccoli, kale, etc) can do this.
The last would be that some root crops can survive in the ground over winter in many areas. Potatoes, carrots, turnips and the like.