Poplar leaf mould

As the task of clearing the vegetable plots continues I needed to find some more composting space to start a new compost heap. I have seven compost bays, each measuring about 5 or 6 feet square and they were all occupied. I emptied one of these that had just leaf mould in it. These were leaves collected up last autumn.

The books generally state that it takes two years for leaves to decompose to produce leaf mould, which is a highly valued soil conditioner. In practice I think the length of time needed depends on the leaves collected. In my case the leaves were almost entirely poplar tree leaves, from the trees that line one of our boundaries. Poplar leaves decompose relatively quickly, unlike say, oak leaves or beech leaves. This is because of the amount of lignin found in the leaves. Lignin is a polymer found in the cell walls of plants and adds structure and stiffness to the cells. Leaves with higher levels of lignin tend to be thicker and shiny.  The relatively flimsy poplar leaves have low levels of lignin so rot down more easily. You probably would need at least two years for oak leaves to decompose. 

My poplar leaves leaf mould was ready to go within the year. I had a decent size heap available once I emptied the compost bay and this will be spread over part of the vegetable bed, along with a lot more compost, during the autumn.