Hydroponic Lettuce Production

Hydroponic Lettuce Production

INTRODUCTION
The hydroponic production of lettuce has revolutionised the salad industry worldwide. Crops can be produced year round, with the benefits of faster, cleaner production and a premium quality end-product. At the same time, newer varieties of lettuce, with improved colours and leaf shapes, have seen the market expand dramatically.

This book is designed to provide essential information of a practical and scientific nature for current and prospective hydroponic lettuce growers. While hydroponic salad crops are often seen as being easier to produce than fruiting crops, such as tomatoes and cucumbers, the degree of skill required to produce a quality product and effectively utilise hydroponic technology is still high. The text explores everything from the background physiology of the lettuce plant, to the details of growing systems and management, raising seedlings, selecting cultivars, nutrition, pests and diseases, and harvesting.

Hydroponic Lettuce Production represents an essential handbook for salad production in the 21st Century.

CONTENTS

CHAPTER 1:
- Introduction
- Background and origin of the lettuce plant
- History
- New Zealand Industry
- Marketing of Fresh Lettuce in New Zealand
- Fresh Cut Produce 12 The Australian Industry

CHAPTER 2: The Lettuce Plant - Germination & Media
- Lettuce Propagation - Seed
- Dormancy and Storage
- Seed Sowing
- Media and Seedling Propagation Containers
- Selection of a Seed Raising Media
- Oasis Blocks
- Rockwool or Growool
- Compressed Peat Blocks/Pellets
- Media and Types of Seedling Propagation Trays
- Composted Bark
- Perlite
- Vermiculite
- Pumice
- Sand
- Scoria
- Expanded Clay
- Germination and Seedling Development
- The Germination Process
- Seed Sowing - Water, Oxygen and Light
- Seedling Nutrition
- Planting Out
- Disease Control During Germination and Seedling Development
- Damping Off Diseases
- Treatment for Damping Off Diseases
- Germination Problems
- Crop Production Problems
- Leaf Colouration
- Temperature
- Lettuce Plant Spacing and Densities

CHAPTER 3: Cultivars
- Introduction
- Lettuce Physiology
- Lettuce Types - The Main Groups
- Crisp Head (Iceberg) Types
- Butter Head (or Boston) Types
- Butter Head (or Boston) Cultivars
- Oak Leaf and Salad Bowl Types
- Oak Leaf and Salad Bowl Cultivars
- Lollo Rossa and Lollo Bionda (Red/Green Frill or Coral) Types
- Lollo Rossa and Lollo Bionda (Red/Green Frill or Coral) Cultivars
- Loose Leaf (or Leaf Lettuce) Types
- Loose Leaf (or Leaf Lettuce) Cultivars
- Cos (or Romaine) Types
- Cos (or Romaine) Cultivars
- Other Hydroponic Salad Crops
- Endive and Chicory
- Chicory and Endive Cultivars
- Chicory - Italian and Catalogna Types
- Endive
- Hydroponic Herbs
- Mesclun Mixes (Mesclun or Saldist)
- Grower Variety Trials

CHAPTER 4: Hydroponic Systems
- Introduction to Hydroponic Systems
- NFT - Nutrient Film Technique
- Lettuce in NFT
- Types of NFT systems and Gullies
- NFT and Rockwool
- Short Run Hydroponics
- Other NFT Systems
- Movable Channels
- Mechanisation
- Pipe Systems
- Floating Hydroponics
- Aeroponics - Root Mist Technique
- Aggregate Hydroponic Systems
- Open Aggregate Systems
- Bag Culture
- Closed Systems - Flood and Drain
- Non Recirculating Capillary Systems

CHAPTER 5: Hydroponic System Engineering
- Setting Up a System
- Gully Size and Slope
- Tank Size
- Pump Selection
- System Layout

CHAPTER 6: System Maintenance
- Electrical Conductivity (EC or CF)
- Electrical Conductivity (EC) Measurement
- Solution pH levels
- The Effect of pH on the Availability of Essential Elements
- pH Adjustment
- pH Testing
- Water Supply
- Water Sterilisation
- Nutrient Sterilisation
- The Greenhouse Environment
- Nutrient Heating and Cooling
- Air Temperatures
- Relative Humidity Levels
- Algae
- Crop Timing
- CO2 Enrichment for Greenhouse Lettuce Crops
- Filters
- Automatic Dosing Systems

CHAPTER 7: Lettuce Nutrition
- Lettuce Nutrition in Hydroponic Systems
- Major Elements Required by Lettuce Crops
- Tissue Analysis
- Functions of Macro, Micro and Beneficial Elements
- Carbon
- Hydrogen
- Oxygen
- Nitrogen
- Phosphorus
- Potassium
- Calcium
- Magnesium
- Sulphur
- Iron
- Manganese
- Boron
- Zinc
- Copper
- Molybdenum
- Chlorine
- Sodium
- Nickel
- Cobalt
- Silicon
- Mineral Disorders of Lettuce
- Specific Lettuce Mineral Deficiency Symptoms
- Lettuce Mineral Toxicity Symptoms
- Nutrient Solutions
- Lettuce Formulations and Nutrient Level Recommendations
- Addition of 'Beneficial Elements'
- Nutrient Conductivity (EC or CF) and pH Implications
- Hydroponic Solution Flow Rates
- Dissolved Oxygen

CHAPTER 8: Pests, Diseases and Physiological Problems
- Pests and Diseases
- Pests - Identification and Control
- Aphids
- Caterpillars
- Slugs and Snails
- Whitefly
- Whitefly Control
- Fungus Gnats
- Birds
- Thrips
- Mites
- Leaf Miners
- Lettuce Diseases - Identification and Control
- Pythium
- Downy Mildew
- Sclerotinia
- Botrytis
- Internal Soft Rot
- Lettuce Ringspot
- Bacterial Infections
- Lettuce Viruses
- Lettuce Mosaic Virus
- Cucumber Mosaic Virus
- Big Vein Virus
- Physiological Disorders
- Tipburn of Lettuce Plants
- Calcium (Ca) and TipBurn
- Glassiness
- Wilting
- Spraying for Pest and Disease Control and Sanitation
- Alternative Pest and Disease Control

CHAPTER 9: Harvesting and Shelf Life
- Harvesting of Lettuce Crops
- Post Harvest Handling
- Cooling and Refrigeration
- Modified Atmosphere Packaging for Fresh Cut Produce
- Packaging Films

REFERENCES

GENERAL INDEX