If it says "PEAT" you are okay.
Sphagnum Moss vs Sphagnum Peat Moss Contact: Diane Relf, Extension Specialist, Environmental Horticulture August 1996
Don't confuse sphagnum moss with sphagnum peat moss. Sphagnum moss and sphagnum peat moss are not the same product. Sphagnum moss is used in the floral industry to line wire baskets and make wreaths. It is the LIVING moss that grows on top of a sphagnum bog. Sphagnum peat moss is used as a soil conditioner by gardeners. It is the dead material that accumulates in the lower levels of a sphagnum bog. Harvesters of the horticultural peat moss remove the top few inches of the live sphagnum moss before harvesting the peat from the lower levels of the bog.
Remember, sphagnum moss is NOT the same as the safe, sphagnum peat moss you use as a soil amendment!
(References: "Don't Confuse Sphagnum Moss with Peat Moss," by Gerry Hood, President, Canadian Sphagnum Peat Moss Association; "Cutaneous Sporotrichosis in Forestry Workers," by K.E. Powell, A. Taylor, B.J. Phillips, D.L. Blakey, G.D. Campbell, L. Kaufman, and W. Kaplan. JAMA 240(3):10, 12-13; and "Multistate Outbreak of Sporotrichosis in Seedling Handlers," by T. England, M.J. Kasten, R. Martin, T. Cote, D.L. Morse, R. David, and J.P. Davis. Journal of the Amer. Medical Assoc. 260(19):2806, 2811.)
Wading Through The Peat Bog
Contact: Diane Relf, Extension Specialist, Environmental Horticulture
Posted April 1997
Garden centers overflow with many products labeled "peats". The key to choosing the correct one lies in identifying the product and knowing how each is useful in the garden.The U.S.Bureau of Mines classifies peats into three major types: moss peat, reed sedge, and peat humus.
Moss peat, usually referred to as "peat moss," is the least decomposed of the three types. It consists of visible fibers of sphagnum, hypnum, and other mosses. Moss peat is lightweight, acidic (pH 3 to 7) and varies in color from yellowish to dark-brown. Its high moisture-holding capacity (approximately 15 times its dry weight) makes it a good soil amendment, or component of potting soil.
Sphagnum and hypnum moss peats differ slightly in their physical characteristics. Hypnum peat decomposes more rapidly, has a higher pH (5 to 7), and re-wets more easily than sphagnum peat. Sphagnum peat develops surface waxes upon drying that make them difficult to re-wet. Sphagnum peat is regarded as superior over hypnum peat for soil amending and as a growing media. The low pH of sphagnum peats (from 3 to 4.5) makes them better suited for use with acid-loving plants such as rhododendrons and blueberries.
Among the sphagnum peats, dark peats (those which are dark brown) are less elastic than lighter colored sphagnums. They will not return to their original volume after compression during packaging. Dark peats also lack the durability of lighter colored sphagnum peats; consequently, they are not as well suited to long-term culture.
Reed sedge peats consist of the remains of reeds, sedges, grasses, and other marsh plants. This type of peat varies considerably in composition and in color (reddish-brown to almost black). Its pH ranges from 4 to 7.5, and its water-holding capacity is less than moss peats (about 10 times the dry weight). Reed sedge peat is finer textured than peat moss. It is not as good a growing medium, but it is useful as a soil conditioner in the garden and in potting soil mixes.
Peat humus originates from hypnum moss, reed sedge peat, or woody peat. It is in such an advanced state of decomposition that the original plant remains cannot be identified. Peat humus is dark-brown to black with a low moisture-holding capacity. Unlike the other peats, it contains a small amount of nitrogen (2 to 3.5 percent). Peat humus, also known as black peat or Michigan peat, is quite heavy compared to the other peats. Its pH varies greatly (from 4 to 8), and it is characteristically sticky when wet.
Two types of black peat are found in the trade. The first, amorphous peat humus is highly acidic and virtually structureless. Any water it holds is mostly unavailable to plants. When it dries, amorphous peat humus becomes lumpy. It turns to dust when broken apart.
The second type of black peat, granular peat humus, contains humates which form aggregate particles. The aggregates give granular peat humus a high air capacity and make it permeable to water. This humus is used for improving very sandy or gravelly soil. Overall, the lack of water-holding and soil-loosening capacities of peat humus make it unsuitable for most horticultural purposes.
Woody peat, although not individually cited in the U.S.B.M. classification, can be purchased separately or as a component of peat humus. Woody peat results from the breakdown of trees, shrubs, and undergrowth from the forest floor. These peats vary greatly in texture, but they are usually quite porous. Woody peats are dark colored and acidic (pH 3.6 to 5.5). They decompose rapidly to become peat humus.
Mixtures of some of the above peat types will be encountered. Under the Federal Trade Commission regulations, a content of only 75 percent peat is sufficient to warrant the use of the term "peat". The best peat mosses contain 95 to 99 percent organic matter. A first-rate reed sedge peat will be 85 to 95 percent pure.
The most abundant constituent plant is usually listed first on the package, but your best guarantee for getting a good product is to buy brand names from a reputable dealer. For price comparison, use dry weight rather than volume since your primary interest is the actual weight of organic matter for your money.
(Adapted from "Wading Through the Peat Bog," by Virginia Nathan, Extension Technician, Consumer Horticulture, Virginia Tech, in The Virginia Gardener Newsletter, Volume 4, Number 1.)
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Edited by agar (04/06/05 07:55 AM)
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