I like to make sure I have a good ratio of green and brown matter in my compost. I have access to a lot of straw but I wonder if there is an advantage to using fallen leaves instead. Is there any difference between them in the nutrient content?
The reason straw is used for animal bedding, not feed, is that it has no nutrient value. It does supply carbon to the compost mix, as you’ve noted. Similarly, just before their leaves fall, trees ‘take back’ the nutrients in the leaves, so that the brown, fallen leaves also have almost no nutrients from the NPK point of view.
The University of Illinois compares the carbon to nitrogen ratios as follows:
| Leaves, ash, black elder and elm | 21-28:1 |
| Leaves, pine | 60-100:1 |
| Leaves, other | 30-80:1 |
| Straw | 40-100:2 |
However, the leaves do retain minerals, which gives them an additional advantage over straw. Plus, if you shred them before adding to the compost, they may break down faster than the straw will. I recommend you take advantage of this autumn ‘gift’ from Mother Nature!