The use of peat in horticulture has been a controversial subject for many years. Not only does the harvesting of peat from bogs destroy precious and unique habitats, but we now know that the process releases large quantities of carbon dioxide, a potent greenhouse gas.
In the late 1990s, the Botanic Garden phased out the use of peat in its growing media and now uses an alternative product, coir. This is made from the composted husks of coconuts. Although this has to be imported, the source is sustainable. Given the wide range of plants grown, it is one of the few alternatives that provides the consistency and attributes needed for effective growing media.