Media and Mixes for Container-Grown Plants: A manual on the preparation and use of growing media for pot plants

324 Pages·1988·6.514 MB·English

by  A. C. Bunt (auth.)

MEDIA AND MIXES
FOR
CONTAINER-GROWN
PLANTS
TITLES OF RELATED INTEREST
Growing media for ornamental plants and turf
K. A. Handreck and N. D. Black
University of New South Wales Press
MEDIA AND MIXES
FOR
CONTAINER-GROWN
PLANTS
(second edition of
Modern potting composts)
A manual on the preparation
and use of growing media for pot plants
A. C. BUNT
N.D.H.(Hons), M.1. BioI.
Formerly with the Glasshouse Research Institute,
Littlehampton, Sussex
London
UNWIN HYMAN
Boston Sydney Wellington
© A. C. Bunt, 1976, 1988
Softcover reprint of the hardcover 1s t edition 1988
This book is copyright under the Berne Convention. No reproduction
without permission. All rights reserved.
Published by the Academic Division of
Unwin Hyman Ltd
15/17 Broadwick Street, London WI V IFB, UK
Allen & Unwin Inc.,
8 Winchester Place, Winchester, Mass. 01890, USA
Allen & Unwin (Australia) Ltd,
8 Napier Street, North Sydney, NSW 2060, Australia
Allen & Unwin (New Zealand) Ltd in association with the
Port Nicholson Press Ltd,
60 Cambridge Terrace, Wellington, New Zealand
First published in 1976 as Modern potting composts
Second edition 1988
British Library Cataloguing in Publication Data
Bunt, A. C.
Media and mixes for container-grown plants:
a manual on the preparation and use of
growing media for pot plants. - 2nd ed.
1. Plants"Potted 2. Compost
I. Title II. Bunt A. C. Modem potting composts
635.9'65 SB418
ISBN 978-94-011-7906-5
Library of Congress Cataloging-in-Publication Data
Bunt, A. C.
Media and mixes for container-grown plants: a manual on the
preparation and use of growing media for pot plants/A. C. Bunt. -
2nd ed. of Modem potting composts.
p. em.
Bibliography: p.
Includes index.
ISBN 978-94-011-7906-5 ISBN 978-94-011-7904-1 (eBook)
DOl 10.1007/978-94-011-7904-1
1. Potting soils. 2. Plants, Potted. 3. Greenhouse management.
I. Bunt, A. C. Modem potting composts. II. Title.
S589.8.B86 1987
635.9'86-dc 19 87-15332
CIP
Typeset in 10 on 11 point Palatino by Paston Press, Loddon, Norfolk
NOTE TO READERS
To assist the reader in the presentation of information, trade
names of products have sometimes been used. This constitutes
neither endorsement of named products nor criticism of those
unnamed.
Every attempt has been made to check the accuracy of the
various media formulae, and no liability can be assumed follow
ing their use.
Contents
List of Tables page xiii
Preface to the first edition xvii
Preface to the second edition xix
Acknowledgements xxi
1 Loam or loamless media? 1
1.1 Loam composts 3
1.2 Loamless mixes 4
1.3 Lightweight mixes with some mineral soil 4
2 Materials for loamless mixes 6
2.1 Peat 6
2.2 Bark 21
2.3 Other organic materials 28
2.4 Minerals 32
2.5 Plastics 36
3 Physical aspects 40
3.1 Physical terminology 40
3.2 Bulk density and total pore space 42
3.3 Water relations 44
3.4 Aeration of substrates 48
3.5 Formulating mixes 53
3.6 Wettability of mixes 59
3.7 Compaction 61
4 Principles of nutrition 64
4.1 Cation exchange capacity 64
4.2 Anion exchange capacity 67
4.3 Availability of nutrients: loam v. loamless mixes 68
4.4 Chemical analysis of lightweight media 70
ix
CONTENTS
4.5 Nutrient uptake by the plant page 76
4.6 Acidity (pH) 79
4.7 Lime requirement 82
4.8 Soluble salts 86
5 Nitrogen 94
5.1 Nitrogen and pot plants 94
5.2 Forms of mineral nitrogen 97
5.3 Slow-release forms 105
5.4 Choice of fertilizer type 111
5.5 Nitrogen and peat 117
6 Other macroelements 120
6.1 Phosphorus 121
6.2 Potassium 131
6.3 Calcium 133
6.4 Magnesium 135
6.5 Sulphur 138
6.6 Slow-release fertilizers 139
6.7 Mineral soil and peat comparison 143
6.8 Nutrient and environment interactions 144
6.9 Fertilizer analysis and salt index 146
6.10 Plant mineral levels 149
6.11 Foliarfeeding 150
7 Microelements 151
7.1 Boron 153
7.2 Copper 156
7.3 Manganese 157
7.4 Molybdenum 158
7.5 Iron 159
7.6 Zinc 161
7.7 Chloride 162
7.8 Aluminium 163
7.9 Fritted microelements 163
7.10 Chelated microelements 166
7.11 Inorganic salts and proprietary fertilizers 168
7.12 Other sources 170
7.13 Microelement availability 171
7.14 Foliar sprays 173
x
CONTENTS
8 Mix formulation and preparation page 174
8.1 Historical 174
8.2 Denmark 175
8.3 Finland 176
8.4 Germany 177
8.5 Ireland 178
8.6 Netherlands 179
8.7 Norway 179
8.8 United Kingdom 180
8.9 United States of America 182
8.10 Hardy nursery stock 187
8.11 Azalea mixes 192
8.12 Protea mix 196
8.13 Proprietary formulations 196
8.14 Mix preparation 197
9 Liquid feeding 201
9.1 Principles of feeding 201
9.2 Formulating liquid feeds 205
9.3 Practical aspects of feeding 219
9.4 Injection equipment 222
9.5 Quality of irrigation water 223
10 Irrigation systems 229
10.1 Drip system 229
10.2 Capillary watering 231
10.3 Flooded benches 233
10.4 Overhead sprinklers 234
11 John Innes composts 235
11.1 Formulation 235
11.2 Compost ingredients: loam 236
11.3 Peat 241
11.4 Sand 241
11.5 Pasteurization 241
11.6 Characteristics and use 243
11.7 Composts for ca1cifuge plants (JIS (A» 247
11.8 Other loam-based mixes 247
12 Heat pasteurization 248
12.1 Thermal deathp oints 248
xi
CONTENTS
12.2 Methods of heat pasteurization Page 250
12.3 Steam 250
12.4 Steam-air mixtures 254
12.5 Flame pasteurizer 255
12.6 Electrical pasteurizers 257
12.7 Other methods 259
12.8 Chemistry of heat pasteurization 259
12.9 Rules for heat pasteurization 264
13 Chemical sterilization 265
13.1 Soil fumigants 265
13.2 Soil fungicides 267
• 13.3 Soil insecticides 269
14 Plant containers, modules and blocks 271
14.1 Clay v. plastic pots 271
14.2 Paper and peat pots 276
14.3 Modules and blocks 277
Appendices 284
1 Metric conversions 284
2 Imperial and us capacity measures 285
3 Illumination and solar radiation units 285
4 Atomic weights 286
5 Formulae and molecular weights of some commonly used
chemicals 286
6 Formulae and molecular weights of some chemicals commonly
used to supply microelements 286
7 Chemical gravimetric conversions 287
8 Temperature conversions 287
Bibliography 288
Index 301
xii
List of tables
2.1 Peat areas and production page 8
2.2 Peat textural grades and particle sizes 12
2.3 The von Post scale for measuring peat decomposition 13
2.4 Composition of three peats (percentage of total organic matter) 15
2.5 Properties of sphagnum peat 19
2.6 Recommended particle size distribution for pine bark and hardwood
bark 22
2.7 Element composition of softwood barks and a sphagnum peat 22
2.8 Average percentage of carbon released as carbon dioxide from woods
and barks over 60 days 23
2.9 Total and 'extractable' amounts of nickel, zinc, chromium and copper
found in sewage sludges 29
2.10 Dry weights and porosity of some potting mix materials 39
3.1 Approximate relationships between units used to measure soil water
tension 46
3.2 Approximate root aeration requirements of selected ornamentals,
expressed as the free porosity Gohnson 1968) 49
4.1 CEC of a sedge peat at three pH values determined by four methods
(from Haynes 1982) 66
4.2 Cation exchange capacities of some materials and mixes 67
4.3 Percentage of added nutrients found by chemical analysis of a mineral
soil compost Gohn Innes) and a peat-sand mix (based on extracts using
water or Morgan's solvent) 68
4.4 Percentage of added nutrients recovered in one litre of leachate from
peat-sand (3: 1) and peat-vermiculite (1: 1) mixes, in I-litre pots 69
4.5 Standards for nitrogen, phosphorus, potassium and magnesium in the
1: 1.5 volume extract (Dutch method) 74
4.6 Standards for ammonium nitrogen, nitrate nitrogen, phosphorus,
potassium and magnesium in the 1: 6 volume extract (English ADAS
method) 74
4.7 Desirable indices for crops (English ADAS method) 75
4.8 Standards for nutrients determined by the saturated media extract
~~ %
4.9 Desirable nutrient balance in saturated media extract 76
4.10 Sulphur-containing materials that can be used for acidification 85
4.11 Interpretation of salinity readings determined by the saturated media
extract and 1 : 2 volume methods 92
xiii