Sphagnum peat moss is valuable in horticulture because its fibrous structure helps it retain a lot of water and air while draining excess water. This has made peat a primary ingredient of soilless growing media (potting mix) around the world. These stable, light-weight, and porous products have been filling the benches, flats, and containers of greenhouse and nursery operators and flower and vegetable growers for decades. You’d be hard-pressed to find a gardener who has not benefited from soilless potting mixes for starting and growing plants, inside and outside.

What’s the problem with peat?

Peat is an organic substance formed from mosses, reeds, and sedges that accumulates and decomposes very slowly in waterlogged soils (bogs). Peatlands hold 30% of the earth’s soil carbon and occur mostly in cold, temperate regions. “Peat moss” used in horticulture typically refers to mosses in the Sphagnum genus.

The problem with peat is three-fold: stripping off peat from peatlands disturbs complex ecosystems; excavation releases enormous amounts of CO2, a major greenhouse gas driving climate change; and demand for peat-based soilless media is growing.

For decades, there have been calls to conserve the U.K.’s dwindling peatlands. Timelines are in place for soon phasing out peat as a growing media for gardeners and commercial growers. Most sphagnum peat is from Canada and there are no indications that Canada, with its vast peat reserves, will follow suit. But public demand for peat-free alternatives will drive the industry to develop new products.

Reducing the use of peat in horticulture will mitigate climate change and increase reliance on local materials as peat substitutes.

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