VSR is a concept that I learned from Joy Larkcom, a person whose gardening style and approach has had a big influence on me. One of the best books on gardening I have ever come across is Joy's "Vegetables for Small Gardens" [Published by Hamlyn, ISBN 0-600-58510-7]. In this book Joy describes her ideas for rating the value of vegetable plants in a way that takes into account not only the yield of a plant (on a helpings per square metre basis), but also the length of time the plant occupies the ground. The rating is further influenced by three additional factors:
1. The availability of the vegetable in Winter, or other times of scarcity. (Do we still have the "Hungry Gap" in late Winter / early Spring?)
2. Whether or not the homegrown item provides significantly better quality than a similar one bought in a shop.
3.Whether the vegetable is difficult and/or expensive to buy.