7 April 2010
In The Garden With the Fluvanna Master Gardeners
By Irene C. Burke - Fluvanna Master Gardener
Fluvanna County Extension Office: 434.591.1950
Peat and sphagnum mosses are harvested, sustainable horticultural products that improve the soil.
Unlike corn and wheat, which are harvested and replaced every year, sphagnum moss and peat are mined like coal; they cant be considered sustainable horticultural products because they are not replaced and their removal permanently damages the environment.
Much of the peat mined today was formed from swamp vegetation trees, sphagnum mosses, grasses and fungi 9000 years ago at the retreat of the glacial ice sheets. Peat grows or builds up at the rate of about a millimeter a year or inch, hardly something that can be quickly and easily replenished.
Consider that undisturbed sphagnum and peat bogs offer continuing flood control, ground and surface water purification and retention, as well as the slow hold and release of sediments and nutrients. They generate plant and animal habitats, whose replacement rarely duplicates the original. For hunters, birders, ecotourists and anglers the loss of such swamps is forever, and most regrettable.
Like surface mines, peat bogs may be reclaimed from degradation. Their restored character, though, differs significantly from their original state and not much is harvested years after the mining. When these swamps are drained and mined they are depleted.
The International Mire Conservation Group (IMCG) of Austria, the Irish Peatland Conservation Council (IPCC), the Peatland Ecosystem Analysis and Training NETwork from the Southern Illinois University, the Convention on Wetlands of International Importance, called the Ramsar Convention and the U.S. Geological Survey (USGS) present consistent information about the state of wetlands in the world and their uses for peat and sphagnum moss extraction, and renewability rate.
However, only the USGS and commercial miners claim that peat is renewable. In Canada, Russia and Finland peat mining and moss scraping is big business.
To say that peat is renewable is like saying that coal is renewable. Renewability is relevant only when the rate occurs within a generation or two 20 to 40 years. That doesnt happen with peat.
The UK, a nation of gardeners, urged their government to set a target for 90% of soil conditioners and growing media to be peat-free by 2010.
In spite of these conflicting political positions the science remains clear. Peat bogs cannot be renewed to their original state producing the same material that was first mined.
When incorporated in garden soil, dried sphagnum moss and peat become compressed, returning the earth to its original condition. Only when mixed at a 1:1 ratio with perlite, does peat moss balance water and oxygen; the same effect can be achieved with perlite and coarse sand. And though touted as a soil improver, sphagnum moss and peat have negligible nutritive value.
For the conscientious gardener, there are renewable readily available alternatives to peat and sphagnum moss, the most important being garden compost, leaf mold; or commercial compost whose origins are knowable and benign. Add to that coir (a waste product from coconut harvesting) and rice hulls.
Tip of the Week
Inventory your garden gloves. One glove does not fit all tasks. Use long waterproof cotton-lined gloves (Spontex Bluettes) when working in gloppy settings. Working with thorny shrubs will require thick leather gauntlets, to the elbow. Try cushioned gloves for repetitive motion tasks like a day of pruning heavy limbs.