Historic note

Title: Characteristics of various peat mosses
Full Citation
Permanent Link: http://ufdc.ufl.edu/UF00065930/00001
 Material Information
Title: Characteristics of various peat mosses
Series Title: ARC-A research report
Physical Description: 7 p. : ; 28 cm.
Language: English
Creator: Conover, Charles Albert, 1934-
Poole, R. T ( Richard Turk )
Agricultural Research Center (Apopka, Fla.)
Publisher: Agricultural Research Center-Apopka, University of Florida
Place of Publication: Apopka Fla
Publication Date: 1977
Subject: Peat mosses -- Florida   ( lcsh )
Genre: government publication (state, provincial, terriorial, dependent)   ( marcgt )
non-fiction   ( marcgt )
Statement of Responsibility: Charles A. Conover and Richard T. Poole.
General Note: Caption title.
 Record Information
Bibliographic ID: UF00065930
Volume ID: VID00001
Source Institution: University of Florida
Rights Management: All rights reserved by the source institution and holding location.
Resource Identifier: oclc - 70912403

Table of Contents
    Historic note
        Historic note
        Page 1
        Page 2
        Page 3
        Page 4
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        Page 6
        Page 7
Full Text


The publications in this collection do
not reflect current scientific knowledge
or recommendations. These texts
represent the historic publishing
record of the Institute for Food and
Agricultural Sciences and should be
used only to trace the historic work of
the Institute and its staff. Current IFAS
research may be found on the
Electronic Data Information Source

site maintained by the Florida
Cooperative Extension Service.

Copyright 2005, Board of Trustees, University
of Florida


2i, Charles A. Conover and Richard T. Poole
A.ri l ural Research Center Apopka
H University of Florida
ARC Research Report RH-77-2

There has always be n some controversy about baled and other peat mosses,

Ah.WABb.vi /'p ~o8d various brands. Many growers buy only German peat or

a particular brand of Canadian peat because they feel it grows the best plants,

while others purchase local peat. Observation of the crops that various growers

produce from these widely divergent peat sources indicates that good quality

plants can be produced in most peats, provided the grower understands good
cultural principles.

Soil components have certain inherent physical and chemical properties

that determine their value for plant production. Peat moss, probably the most

widely used soil amendment provides high cation exchange capacity (fertilizer
retention) water holding capacity (ability to hold water against the pull of

gravity) and at the same time provides aeration (oxygen to the roots).

Soil Aeration is an important factor not realized by many plant growers.

Growth of foliage plants is often reduced and sometimes plants are killed be-

cause of inadequate aeration caused by overwatering in combination with improper
potting mix ingredients.

Roots cannot absorb water or nutrients except in the presence of oxygen.

During growth processes, roots emit carbon dioxide which can become toxic

unless removed. Potting mixtures must allow for rapid air exchange between the

medium and the atmosphere so that carbon dioxide is removed and oxygen supplied

to roots. Factors in the media which affect aeration include particle size,

uniformity, types and irrigation practices. Small pore spaces hold water against

the force of gravity and air will be unable to move into such spaces until water

is removed by plant absorption or evaporation. Plants obtain most of their

water from small pores, but larger pores provide necessary aeration. When pores

are too small, mixtures will remain wet for long periods and reduce aeration, if

pores are large poor growth may result because of lack of water. Pore space

of good quality foliage potting mixtures varies between 5 and 30% by volume

after removal of gravitational water. A measurement of non-capillary pore

space is an indication of aeration existing after watering but oxygen supplied

from capillary pore space exists only after water in these pores transpires or

evaporates. Therefore, adequate non-capillary pore space is necessary to

provide aeration of root systems.

Cation Exchange Capacity (CEC) refers to the ability of soil to retain nutrients

against leaching effects of water and to release them for plant growth. Peat

mosses are usually high in CEC and provide buffering action to prevent rapid

changes in nutrient availability and pH. Materials with a high CEC have a high

nutrient reservoir, whereas, potting mixtures or components with low CEC retain

small amounts of nutrients and, therefore, require more frequent applications

of fertilizer than soils with high CEC.

Rapid changes in soil acidity or alkalinity (pH) can be prevented by

using a soil with high CEC, but if pH correction is necessary, more corrective

materials will be required in high CEC soils (that is why so much dolomite or

limestone is necessary to raise the pH in peat moss).

CEC is measured by the number of units of nutrients held by a given

quantity of soil (millequivalents (meq) per 100 grams (g) of soil). CEC of

5-40 meq/100 g or 20-50 meq/100 cc is satisfactory for good plant growth.

Very high CEC levels are not desirable either, if excessive fertilizer is applied,

it will be very difficult to leach it from peat moss. The use of meq/100 g can

be misleading when discussing soil mixtures with high organic content, and meq/

container or unit volume gives a more realistic indication of the character of

the soil mixture.

Water Holding Capacity (WHC) is the amount of water held by soil after free

drainage has occurred and is expressed as percent dry weight or percent volume.

This water is the water most readily absorbed and used by plants. The

amount of water held against the pull of gravity (free drainage) will depend

upon the surface area of media particles per unit volume, the absorptive
properties of ingredients, attractive forces acting between water and the

particles and size of container. Small containers require a more open

potting mixture than larger sized pots because of friction forces of pot

walls and height (pull) of gravity. Small size pots containing potting

mixtures having high water holding capacities are oftencompletely saturated

because the gravitational pull is not large enough to remove water. However,

the same potting mixture in a larger pot will have better aeration because

gravity will pull some water from the upper portion of the pot. Available

water held, rate of water movement and speed water enters the root zone are all

influenced by potting mixture. A water holding capacity of 40-100 percent by

weight or 20-50 percent by volume is satisfactory for foliage plant potting

mixtures but it is higher in most peats. In the case of peat mosses, higher

water holding capacities are acceptable, provided they are mixed with materials

with lower water holding capacities so that the final average is within the

desired range.

Data that follows on 12 peat mosses was obtained from unopened bales in

the case of the 11 baled peat mosses, and by measurement of a full load of the

Florida peat (Table 1). All the baled peat mosses were shredded through a

Lindig Model -M4 shredder with water (about 20 gal) injected at time of shredding.

The concentrated peat moss was allowed to absorb water until it ceased to

increase in size. Each of the physical and chemical samples listed below is

an average of 4 samples.

Cost Although baled peat mosses contain 6 cubic feet of material, there

has always been some contention that there was variation in yield after shredding.

Table 2 shows results of the test.

Table 1. Sources of peat moss used in these tests.

Product No. Product Producer

Canadian Peat Moss

Cottage Brand Canadian

Detorf Garden Peat

Fafard Canadian Sphagnum
Peat Moss

First Prize Canadian
Sphagnum Peat Moss

Granulated Conc. Peat

Lambert Canadian Sphagnum
Peat Moss

Peace River Peat Moss

Premier Professional
Bale Sphagnum Peat Moss

Premier Sphagnum Peat Moss

Special Corase Canadian

SPS Sphagnum Peat Moss

Packaged for AGS
Western Peat Moss Ltd.
Vancouver B.C. Canada

Hyde Park Products Corp.
New Rochell, NY

J. M. Trading Corp.
Chicago, IL

Fafard Peat Moss Co., Ltd.
Springfield, MA

Grande Anse Peatmoss Co. Ltd.
Belmont, MA

Western Peat Moss Ltd.
Vancouver B.C. Canada

Riviere Quille
Quebec, Canada

Peace River Peat Co., Inc.
Bartow, FL

Premier Peat Moss Corp.
New York, NY

Premier Peat Moss Corp.
New York, NY

Western Peat Moss, Ltd.
Vancouver BC. Canada

J. M. Trading Corp.
Chicago, IL

Table 2. Peat moss costs per cubic foot of
shredding 12 peats.

product obtained after

Cost, $/ft3 1977 Grower cost, $/bale Yield, ft3/bale Product No.

.35 9.50/yd -- 8

.48 5.40 11.16 7

.50 5.95 11.98 5

.51 6.20 12.21 1

.54 5.40 9.93 2

.55 6.20 11.19 4

.59 5.60 9.46 9

.70 6.60 9.46 11

.72 7.80 10.85 10

.74 7.80 10.60 3

.75 8.30 11.00 12

1,33 4.00/bag 3.00 6

Quality Measurements of quality relate to cation exchange capacity, water

holding capacity, pore space, pH and soluble salts level. Table 3 shows that

cation exchange and water holding capacities, pH and soluble salts are at or

above suggested levels.

Table 3. Cation Exchange
salts levels of

and Water Holding
12 peats.

Capacities, pH and soluble

Product No. meq/cc by volume pH Soluble salts*

1 3.10 73.45 4.2 0

2 4.44 33.65 4.0 0

3 3.17 71.62 4.4 0

4. 3.65 66.58 4.1 0

5 7.60 77.82 3.9 5

6 6.25 80.36 3.7 205

7 5.80 45.48 4.0 10

8 2.86 67.32 3.8 210

9 3.85 76.44 3.8 70

10 6.90 35.26 3.9 224

11 2.75 88.61 4.2 0

12 1.20 51.89 4.0 31
*Soluble salts levels as high as 1000 ppm would be considered acceptable -
500 ppm or below is suggested.

The major problem noted in several of the peats was poor aeration as

demonstrated by the low percentage of non-capillary pore space (Table 4).

Peats 4 and 7 are unacceptable unless amended with coarse components, while 1

and 6 are marginal. Table 4 lists the various peats in order of decreasing

aeration as measured by non-capillary pore space. Any peat with a percentage

below 7.5 percent would be a poor choice for a propagation bench or for use alone

in pots.


Table 4. Non-capillary, capillary and total pore space found in 12 peats.

Non-capillary Capillary Total Product

pore space % pore space % pore space % No.





































In summary, selection of a peat moss depends on personal preference,

cultural practices, cost and availability. All peat mosses listed are capable

of growing plants, but cultural practices are less stringent for peats with

the better physical characteristics.

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