“To quote Robert Parnes, 'the vegetable garden is an endless sinkhole for plant nutrients.' It has to be. Many kinds of vegetables require extraordinarily rich soil to grow well. Vegetables were like that during Roman times, and they still are. It’s in their genes. But sustainable, biologically oriented farming aimed at producing nutrient-density in field crops operates at lower levels of soil fertility than a garden requires. A farm can export some organic matter; a garden, never.” - Steve Solomon, The Intelligent Gardener