The difference between "aged" and "composted"
Horse manure can be composted, but not on its own. A little effort and monitoring is needed - even if the manure has already been sitting for a long time. Many people refer to their old pile of manure as “aged” which does not always mean composted. Using raw or improperly-composted manure as a fertilizer will not only be smelly, but can also harm the health of your pastures and gardens. If you have manure that has been sitting untended for a while, then here is what you can do to make sure it becomes an odour-free and nutrient-rich fertilizer.
How to compost your aged pile of manure
When composting anything from food scraps to animal waste, monitoring the changes in temperature is critical. Horse manure has to reach a temperature of at least 55 degrees Celsius. This will eliminate all the bacteria and unwanted plants or pests. If the temperature is not rising, then the manure is not composting. Carbon- or nitrogen-rich components will need to be added to create an ideal balance of the two, or else you may need to turn the pile (by hand or mechanically).
The key to composting manure is proper air flow- this is the reason why a pile of manure cannot compost by itself, as not all parts of a pile are exposed to the air. If you cannot turn it by hand, then you can spread out the pile and insert PVC pipes for self-aeration. Once the temperature rises it will eventually begin to fall and return to air temperature. At this point, your manure should be fully composted. To produce quality compost the use of a thermometer is recommended to monitor these important changes. Within three weeks or more you can turn your aging pile of horse manure into a natural resource!
A composting thermometer indicating the temperature of a pile of manure.