One of the easiest and most effective ways to improve and build soil fertility in any gardening situation is to use a method known as sheet mulching. Thick layers of mulch are placed directly on the soil, simulating the thick leaf litter and humus found in natural forest systems. Sheet mulch provides multiple benefits, including water retention, weed suppression, slow release of nutrients and increase of beneficial soil organisms.
I first was introduced to this method through a sweet old lady called Esther Deans. She had written a book called 'Growing without digging', and was one of the first people in Australia to promote this type of garden. Her simple method enabled anyone to quickly create an extremely productive garden in any soil, even directly over weeds or lawn. The somewhat chaotic garden in illustration 1 is one of my early mulch gardens, made on shallow sandy soil over solid rock!