Good compost results from a healthy balance between nitrogen-rich ‘green’ materials and carbon-rich ‘brown’ materials. Different types of materials and proportions affect the rate of composting and this is more an art than a science. Too much nitrogen and the contents will be wet and smelly; too much carbon and it will be too dry and will compost very slowly. Keep an eye on moisture and odour and you’ll get it right. Dry autumn leaves, which are falling all around us now, are an excellent ‘brown’.