Coffee grounds from restaurants Pine needles for plants who like acid conditions, such as blueberries. Saw dust , but avoid excess quantities as it increases the soil carbon content. Hair is high in nitrogen and a good insulator for the fibrous surface roots. Seashells , ground to chips, discourages slugs and snails due to their sharp edges. Leaves should be shredded, as they readily pack when wet and make leaf mould, which is more valuable tilled in or composted.
Leaves have more nutrients, pound for pound, than manure has.
Seaweed is great as it is high in minerals.