The limits of sustainability of peat as a soilless media for agriculture

Soilless media has long been used to improve fertilizer and water use efficiency of high-value crops in containers, and global demand for these media is predicted to increase 250% to 400% in the next 25 years. The environmental impact of all soilless media products warrants detailed analysis. The unique properties of peat make it the most widely used product. Peatlands are vital carbon stores and the historical degradation of European bogs has prompted regulations restricting peat extraction. Unlike Europe, North American peatlands-particularly in Canada-are largely pristine and have the potential to be sustainably managed. A focus on restoration, coupled with limited human interaction in remote peatlands, means that Canadian peatlands are currently accumulating carbon faster than the rate of extraction for containerized crop production. However, the steadily increasing use of soilless media for high-input agriculture may drive-up international demand for North American peat, requiring careful management to maintain sustainability. Several alternative products have been studied but our review of seven life cycle assessments reveals that their environmental impact is similar to or greater than peat. The expansion of high-input agriculture means that multiple soilless media components will be needed to feed our growing population.