The RHS is acutely aware of the environmental concerns surrounding the use of peat in horticulture – for more information please see the RHS statement on peat.
The commercial extraction of peat for use in gardening is unsustainable and leads to the destruction of peatlands. This land is important for biodiversity, carbon storage and flood-risk management, so should be saved. With few exceptions the use of peat in horticulture is unnecessary.
To reduce gardeners’ reliance on peat we are looking at sustainable alternative growing media. A key element to successful alternatives is how they are watered and then retain moisture. Our research is studying this element in particular and also the consistency of the material sold to gardeners.
Because of our expertise in the area, the RHS is represented on a panel to advise Defra, the Government’s environmental department, on how best to replace peat with other sustainable materials. Peat accounts for less than 0.7 percent of all growing media and soil conditioners used by RHS Gardens.
What is peat and how is it used?
Peat is made of incompletely decomposed plant remains, mainly sedges, grasses, reeds and mosses, formed when waterlogging and the exclusion of oxygen affect the natural processes of decay. It is a slow process, with the layer of peat increasing by an average rate calculated to be no more than 1mm (1/16in) depth per year. It is used in horticulture for its unique characteristics that make it an ideal growing medium.
Alternatives to using peat
Peat alternatives are now being developed using materials such as bark, wood fibre, coir, biosolids, bracken and green compost. We have undertaken a number of comparative trials at our gardens on peat and peat alternatives, to help gardeners understand the options available to them.
RHS projects on peat
We believe that the commercial extraction of peat at current rates is environmentally unsustainable because it is removed at a much faster rate than it can accumulate. This will lead to the irreversible destruction of peatlands, so it is important that gardeners understand the severity of this problem and that there are alternatives to peat.