The use of wood pellet stoves and boilers in the Northwest Territories is increasing quickly as more people convert to biomass heating systems. Approximately 90 tonnes of wood pellet ash were produced from industrial, commercial and residential boilers and stoves in 2013.
Samples of fly ash and bottom ash from wood pellet boilers and stoves were analyzed to determine their suitability as an agricultural soil amendment, including fertilizing potential as well as testing physical characteristics and concentration of elements or compounds that could be toxic or limiting to plant growth. Wood pellet ash is rich in potassium and certain micronutrients. It is also highly alkaline and has high acid neutralizing values. The author found that wood pellet ash added safely to compost at a maximum of 5-15% of total compost weight can enrich it in a variety of nutrients. Ash can be a valuable addition to compost especially during the early decomposition stages. Wood pellet ash must be monitored in compost in order to avoid alkaline shock and reduced productivity.
If you'd like to know more about this study please feel free to read the final report here.