Larger yards, especially those with long hedges, can generate huge quantities of woody waste. We'll consider what to do with it later, but why is it a particular problem?
First, prunings, hedge trimmings, and woody material generally have a high C:N ratio, so they are high in carbon and low in nitrogen. This in itself slows down decomposition, but that's only half the problem. The other half is that cellulose is only one of the carbon-rich materials in plants. Another, which may make up 20-30 percent of wood, is lignin. Lignin's chief disadvantage is that composting bacteria are not good at breaking it down.
Second, woody waste has much bigger stems than green waste, so it has a low surface area compared to its volume. This doesn't give bacteria and other organisms much to work on.
The third problem is the exact opposite of that afflicting a pile of grass mowings, which collapses and runs out of air. A pile of raw prunings, by contrast, contains far too much air, and dries out too quickly. For some gardeners, these problems seem so intractable that composting doesn't look like a serious option. But
Was this article helpful?