This is a public-interest archive. Personal data is pseudonymized and retained under GDPR Article 89.

Re: [SHADEGARDENS] Unfinished Compost

On Thu, 29 Jan 1998, Alex Waterhouse-Hayward wrote:

> "Peat moss is cheap," said Bill Nash from Guelph, Ontario. So Bill where
> does most of the peat moss that is sold in North America come from? Can this
> stuff be manufactured or is it an unrenewable resource? Why would some
> gardeners try not to use peat moss? What environmental concerns might they have?

"Peat" is partially decomposed wetland plants.  "Peat moss" typically
refers to Sphagnum, a wierd and wonderful genus of wetland mosses.
"Sphagnum peat" is partially decomposed Sphagnum moss.  But there are
other sorts of peat... what's commonly sold in the US as "peat"  is
actually sedge peat, partially decomposed sedge plants.

What are the virtues of peat?  Like compost, it holds water and has pretty
good cation exchange capability (though nowhere to the extent of clay).
There are rarely many viable seeds present, and those seeds that are there
aren't going to like most garden conditions.

Sphagnum moss has an amazing ability to hold water and release it
gradually; in addition, it is very slow to decay, and has naturally
occuring compounds that inhibit bacterial and fungal growth.  Long strand
(whole) sphagnum has been used for years for layering plants (making
cuttings still on the plant); chopped sphagnum for water retention in
greenhouse soils, and milled sphagnum, lightly dusted over the tops of
freshly planted flats of seeds, helps prevent damping off while retaining
moisture for germination.

What's wrong with this picture?  As traditionally used, peat and sphagnum
production are generally not sustainable, and the wetlands where the
sphagnum grows and peat forms are pretty fragile ecosystems.  The harvest
method is basically strip mining.  Regrowth in mined areas is slow, and
many of the plants dependent on peat soils are lost from the area.  Though
there are still tremendous amounts of peat in North and South America,
European peat cutting has been down for many years.  Sustainable peat
cutting operations require great attention to detail, much like the ones
demonstrated at Wicken Fen in England.

Because of the environmental damage, many people prefer to use coco fiber
or compost (both sustainable) in place of most peat and sphagnum use,
reserving sphagnum for the jobs it does much better than anything else
available... milled sphagnum for seeds that are very prone to damping off
(sand or chicken grit does as well for most seeds), and long strand
sphagnum for things like air layering (ls sphagnum can often be reused
several times for layering).

For quick fixes for crummy garden soil (something much of the bagged peat
has been sold for), a combination of compost, wood chips, and maybe some
of the acrylamide water gels seem to work as well as digging in bags of
peat.

Kay Lancaster    kay@fern.com
just west of Portland, OR; USDA zone 8
Other Mailing lists | Author Index | Date Index | Subject Index | Thread Index