Our aim as organic gardeners is to work in harmony with natural systems and minimise and replenish the resources our gardens consume. However, in some instances we work against nature. In a natural environment, a carrot develops a long, fat root which provides food for the plant until it produces flowers, then seeds. With its mission complete, the carrot dies and the root slowly rots back into the soil, replacing almost all the nutrients it absorbed. However, we come along and pull it out, so we need to complete the cycle by replacing the nutrients we remove. This is where organic fertilisers come in...