This professional horticulture reference, which has been in print continuously since 1932, is fully revised and updated in this new edition. Based on real-life experiences from industry professionals including growers and equipment and greenhouse manufacturers, the presented information covers all aspects of greenhouse equipment—the structures themselves, benches, irrigation, curtains, environmental controls, machination, and the greenhouse as a retail facility. The most recent developments in greenhouse evolution are discussed, as are the varieties of available greenhouse structures, from freestanding and gutter-connected greenhouses to shade houses and open-roof greenhouses. Information on the business side of managing a greenhouse is provided, including how to market products and how to operate a retail store from a greenhouse.
|Edition description:||Eighteenth Edition, 18th edition|
|Product dimensions:||7.30(w) x 10.10(h) x 0.90(d)|
About the Author
Chris Beytes is the editor of GrowerTalks magazine and has been a professional horticulturalist for nearly 30 years. He lives in South Elgin, Illinois.
Read an Excerpt
Volume 1 Greenhouses and Equipment
By Chris Beytes, Rick Blanchette
Ball PublishingCopyright © 2011 Ball Publishing
All rights reserved.
What Is a Greenhouse?
P. Allen Hammer
What is a greenhouse? A typical dictionary definition may simply read, "a building having glass walls and roof, for the production of plants." Most greenhouse owners and growers, however, would argue that this definition is much too simple because it excludes greenhouses covered with various plastic glazing materials. As you read and use the RedBook, it will become apparent to you, too, that it takes a much broader definition of greenhouses to define the growing structures used in floriculture production.
Controlling the Environment
Greenhouses are considered "intensive" agricultural production. Intensive agriculture requires large inputs of labor and capital per unit of land to produce crops with high value per unit of land. That's opposed to "extensive" agriculture, which requires large inputs of land per unit of labor and capital with low crop value per unit of land. That is the major difference between field production and greenhouse production.
But before we more accurately define a modern greenhouse, it's important to understand a critical concept: controlled environment.
In nearly all horticulture production, we control the environment by using a structure along with other mechanical additions (e.g., heat) to create the modified environment. Although we have the engineering expertise to create a fully controlled environment for plant growing — up to and including artificial sunlight — the high cost of building and operating such an environment makes it unprofitable in most production. The exception has been in tissue-culture and seed-germination chambers, but those chambers contain high-value output per square foot of growing space and require less artificial light inputs.
The USDA Report No. 89, A Global Review of Greenhouse Food Production (Washington, D.C.: U.S. Government Printing Office, 1973), provides a more accurate definition of a greenhouse, "A greenhouse is a frame or inflated structure covered with a transparent or translucent material in which crops may be grown under conditions of at least partially controlled environment, and which is large enough to allow a person to walk within them and carry out cultural operations." This definition would include unheated structures with a roof that keeps rain off the crop and helps maintain warmer night temperatures as well as shade structures used to reduce wind and light.
Greenhouses use solar radiation as their primary source of "light," which is the most expensive input to try to add artificially. An important part of the greenhouse definition to me is the phrase "transparent or translucent" glazing because it includes all the commonly used coverings: poly, rigid plastic, glass, retractable-roof coverings, and shadecloth.
The sophistication of a particular greenhouse is often related to the climate in which it is constructed. Greenhouses located in the southern United States, for instance, often have less environmental control capability than those located in the north. However, this trend continues to change. Most greenhouses built in the last five years, regardless of location, are equipped with some form of computer system that operates the greenhouse's heating, ventilation, and cooling equipment with great precision. This is because the demands for better product quality and more precise timing have become increasingly important to growers in order to meet market demands.
The Greenhouse Effect
A discussion of greenhouses wouldn't be complete without a mention of the term "greenhouse effect." The terms "global warming" and "greenhouse effect" continue to be in the world news. Many misunderstand these terms, and global warming is often incorrectly associated with greenhouses because of the term "greenhouse effect."
The "greenhouse effect" is the possible warming of our planet because of increased levels of carbon dioxide and other so-called "greenhouse gases" in the earth's atmosphere. These gases occur naturally in the atmosphere as well as being released into the atmosphere from human activities — cars, factories, and so forth. For example, carbon dioxide is transparent to solar radiation but is opaque to long-wave (heat) radiation coming from the earth's surface. The carbon dioxide traps the heat near the earth's surface exactly like the glass does in a greenhouse. This is where the term "greenhouse effect" originated. Increased carbondioxide levels in the atmosphere are created by burning solid wastes and fossil fuels, not from greenhouse production. (It's interesting that this term doesn't technically apply to a polyethylene plastic-covered greenhouse because plastic is transparent to long-wave radiation. That's the reason infrared inhibitors have been added to plastic glazing used for greenhouses and the reason heat-retention curtains can be important in plastic greenhouses. Engineers have attempted to create the greenhouse effect with plastic glazing.)
Regardless of how a greenhouse is defined, floriculture crop production most often occurs in a modified environment. The future will no doubt require even better environmental control. Greenhouses will continue to be used and will become increasingly sophisticated because even under the best of natural climates, floriculture production requires modification to the environment.
Scott S. Thompson
A freestanding greenhouse is just what the name implies: a structure that's not attached to another structure. It may be a simple arch shape with no sidewall, have sidewalls just a few feet high, or have sidewalls 8-10' (2.4-3.0 m) high. This is in contrast to the other common greenhouse design — the gutter-connected house — in which numerous houses, or "bays," are connected together to create one large greenhouse.
A Little History
"I just want to say one word to you. Just one word. Plastics." No, that's not something my father once told me, but a line I heard in the movie theater while watching Dustin Hoffman get career advice while being chased around the pool by Mrs. Robinson in the 1960s classic The Graduate. Synthetic plastics, specifically polyethylene film, or "poly" as it's called in the trade, helped create the modern bedding plant industry and was the driving force behind modern freestanding greenhouse design.
Before World War II, all greenhouses were built of wood, iron, or steel and were covered or "glazed" with glass. World War II forced the aerospace and shipbuilding industries to develop lighter and stronger products to supplement steel as a raw material for the defense of our country. Advances in plastics technology spawned a tremendous variety of new market opportunities in diverse businesses, including agriculture and horticulture.
Prior to the development of sheet plastics, greenhouse structures were designed and built for glass covering. With the advent of polyethylene plastic sheeting, farmers, florists, and nurserymen could now use this new "slat film" to cover existing small, wooden cold frames that were once glazed with more expensive, fragile, and heavy glass. Although the poly was thin, short-lived, and only available in narrow 2' (61 cm) or 3' (91 cm) widths, it allowed new growers to get into the business with a minimum of time, effort, and capital. However, the continued success of poly demanded production of wider, longer-lasting films. The original 3' (91 cm) wide material only lasted three or four months, depending upon the region of the country in which it was installed. At the time there were no ultraviolet (UV) inhibitors in the film, resulting in a quick breakdown of polymers, elasticity, and strength.
As poly became available in greater widths, greenhouse builders developed frames made of materials other than wood, such as steel, to offer a product that rivaled wood in size, shape, and strength, but cost less and required considerably less maintenance over the useful life of the structure. This also offered an alternative to costly steel-and-glass structures. Potential greenhouse construction costs could be cut from $4.00-7.00/ft.2 ($43.00-75.00/m2) for glass to as little as $0.80-1.50 ($8.50-24.00/m2) for steel frames covered with poly.
The first design profiles were crude and basic, but effective. Weather and wind were figured in the concepts, but at the time the actual considerations for stress and durability were new and untested. The only real data was for Quonset or arch-style roofline buildings covered with corrugated steel, or tent construction, which is still considered temporary. The Quonset (named for the city in Rhode Island near which the original military buildings were manufactured) was fairly easy to fabricate and cover; however, the available poly covering was still only wide enough to go partially across the frame. Cover separation had to be incorporated with the frame design to allow for completion of the securing process. This required the addition of a framing member rigid enough to span the rafter bows and to create an opportunity to either nail or staple the poly to this framework. These buildings were typically either a one-or two-piece construction with widths from 14-30' (4.3-9.1 m) and lengths of up to 200' (61 m). The structures had posts or stakes driven 2' (61 cm) or 3' (91 cm) into the ground, depending on the size and location of the greenhouse. These developments resulted in an entirely new steel greenhouse design for the market to consider. However, lumber was still necessary in the framework to secure the poly covering.
Enter aluminum. The design staffs of greenhouse manufacturing companies worked closely and quickly with construction supervisors and other skilled craftsman in the building community to develop realistic ways to consider incorporating a positive and secure system to fasten the poly. The ability to reuse the fastening system would help offset the increased costs associated with a two-piece aluminum poly "lock." The first covering systems were mechanically based, with bolted or screwed base pieces used to cover the top of the greenhouses with poly. The covers were secured with rods that clamped them in place, allowing the poly to cover the walls down to the ground. Now covers could be installed quicker and easier. Also, for energy conservation purposes, builders began using two layers of film, inflating the layers with a small "squirrel cage" blower, creating the effect of insulation similar to a giant storm window. The poly fasteners could secure either one or two layers. (This same technology was also adapted to gutter-connected houses.)
The freestanding poly greenhouses could now be built, covered, and put to use in a matter of days, compared to weeks or months for a glass-covered greenhouse. The basic uses for these greenhouses were similar, but there now seemed to be a greater emphasis on using the structures for starting material from seed, such as starter plants for vegetable field crops, as well as for overwintering woody and perennial nursery crops. Bedding plant and potted plant growers who were using glass greenhouses began experimenting with growing their crops in the new poly structures. Immediately it was determined that the plastic-and-steel structures had many advantages over the glass-covered structures. The plastic greenhouses were considerably tighter than glass houses, which had laps between the panes that leaked air. The solar gain was equal to or greater than glass (even with approximately 15% less light transmission), and they held temperature much longer. These environment changes were now creating distinctly different reasons to use greenhouses for a variety of cultural applications. A whole new growing environment was available for various plant material and to traditional growers as well as the new breed of poly-greenhouse growers.
This tighter greenhouse environment now required more control. Glass greenhouses had for decades been heated with huge boilers that burned coal, oil, and natural gas to create steam or hot water, and were ventilated naturally by convection through the roof and sides. Experienced greenhouse builders had already been providing alternative heating and ventilation equipment (similar to what was being used successfully in livestock buildings) to glass greenhouse owners, specifically institutional and research facilities, who demanded the ability to create climate zones within their greenhouses. Freestanding poly greenhouses could be heated by small, oil-, gas-, or LP-fueled forced-air heaters. Ventilation was also done mechanically, with intake shutters or louvers on the intake end and electric exhaust fans on the outlet end.
Traditional glass growers were now thrown a huge curveball as new production greenhouses could be built and start producing plants almost immediately. This dramatically increased the amount of players in the market and decreased the time it took to produce plants for market. The same types of plant material could be grown in a shorter period of time for less capital outlay while still generating the same market price. The commercial greenhouse production market was changed forever.
In the years since the first freestanding poly-covered greenhouses were built, the greatest changes have been in the development of the plastic coverings. Longer life, greater widths, condensation and heat-conserving additives, shading enhancements, and rigid plastic panels rather than sheets or rolls are all choices that growers need to consider when deciding on cover. For a time, polyester-based fiberglass reinforced paneling (FRP) was popular. Glass growers could transition to the freestanding FRP greenhouse with less culture shock than switching between glass and poly. Glass growers who wanted freestanding buildings could build a house covered with the corrugated fiberglass sheets at dramatically reduced costs and not deal with the labor hassles of recovering with film every two or three years. However, the love affair with FRP ended when it was discovered how easily and quickly fiberglass burned, destroying entire ranges instantly.
There have been continuing refinements in a variety of other areas: stronger, lighter, and more corrosion-resistant framing materials, as well as wider, taller, and longer building profiles. In addition, improvements have been made in the development of more user-friendly hardware connections and in integration of environmental controls, including temperature, humidity, light levels, irrigation, and weather forecasting.
Because of increasing energy costs, freestanding greenhouse designers have recently adapted the natural ventilation used by widespan glass greenhouse producers. These designs incorporate the use of roll-up sides and roofs, hand cranks, or automatic gearboxes, which allow air to flow passively through the house at a fraction of the energy cost of fans.
Excerpted from Ball Redbook by Chris Beytes, Rick Blanchette. Copyright © 2011 Ball Publishing. Excerpted by permission of Ball Publishing.
All rights reserved. No part of this excerpt may be reproduced or reprinted without permission in writing from the publisher.
Excerpts are provided by Dial-A-Book Inc. solely for the personal use of visitors to this web site.
Table of Contents
1 Greenhouse Structures
What Is a Greenhouse? 1
Freestanding Greenhouses 2
Gutter-Connected Greenhouses 5
How High? 9
Going Up? 9
Open Roof Greenhouses 11
The Headhouse 19
2 Greenhouse Glazing
Glazing: It's What Makes the Greenhouse 23
Polyethylene Film 28
Rigid-Plastic Glazing 32
Glass Glazing 35
Greenhouse Glazing 101 37
From the Top DownRecovering Poly Greenhouses 38
3 Curtain Systems
Curtains? In a Greenhouse? 43
Types of Curtain Systems 44
Photoperiod Control 52
4 Benches, Floors, and Baskets
Greenhouse Benches 55
Ebb-and-Flood and Trough Benches 59
Growing on the Ground 63
Growing Overhead 65
The Science and Art of Watering 69
The Top Three Ways to Water: Hand, Overhead, and Drip Irrigation 71
Boom Irrigation 73
Capillary Mats: Another Way to Subirrigate 83
Drip Line or Flood Zone? 83
Mist Systems for Propagation 84
Fertigation Equipment 89
Understanding Turndown Ratio 93
Water Recycling and Sanitation 95
6 The Greenhouse Environment
Greenhouse Ventilation 107
Greenhouse Heating 114
Biomass Heating 122
Four Levels of Climate Control 125
The Latest Horizontal Airflow Technology 128
Supplemental Lighting 129
Carbon Dioxide: Building Block for Plant Growth 132
Alternative Energy: Does It Pay? 134
Media Mixing 139
Flat and Pot Filling 142
Automatic Transplanters 146
Machine Vision in the Greenhouse 155
Ten Ways to Figure Payback 160
Lean Flow in the Green Industry 162
8 Internal Transport and Logistics
Walons, Carts, and Monorails 167
Keeping Track 168
Movable Benches 171
Forldifts, Cranes, Wagons, and Robots 173
Case Study: Barcode Tracking in a Modern Plug Facility 175
Bar Codes Stink 179
9 Pest Control Equipment
The Basics of Greenhouse Pest Control 183
Pesticide Application Equipment 185
Insect Screens 187
Chemical Storage Facilities 191
EPA Worker Protection Standards 194
10 Greenhouse Sustainability
The Concept of Sustainability 197
11 Specialized Facilities
Storing Seeds Successfully 201
The Proper Boiler Room 204
12 Putting It All Together
Site Selection and Analysis 209
Growing Your BusinessFor the Right Reasons 212
13 Managing Your Business
The Greenhouse Office 219
14 Marketing Your Business and Your Products
Building Your Businesss Image 229
Ten Laws of Niche Marketing 232
15 Retail Facilities
Retail Greenhouse Design 235