Monday, November 26, 2007

Module 12 - CO2 Fertilization and Greenhouse Presentation, DUE Tuesday December 4.

San Remo is called the Town of Flowers where beautiful roses, sweet-smelling carnations, and colorful begonias and camellias are cultivated. With exceptional climate, the heart of Italy’s floriculture region is in San Remo. Note the HAF fans (Blue) and CO2 injectors (Red). Image Source: Dr. Sandy Wilson, University of Florida.

(see note about exam at bottom of post).


As we learned earlier in the semester, CO2 provides carbon to the growing plant when the physiological processes of photosynthesis and respiration achieve balance. Depending on the environmental control taking place in the greenhouse it can be beneficial both from a plant growth and economic standpoint to add supplemental CO2 to the greenhouse. After all, approximately 40% of the dry matter of most plant species consists of carbon.

Supplemental CO2 is most beneficial during periods when the greenhouse is not venting very regularly and supplemental light is being applied (or natural light is abundant). Conditions such as these are usually found during the winter production months. It is also important to remember that as transpiration rates increase the capacity for CO2 uptake increases for most plants with C3 photosynthesis.

  • Explain the impacts of supplemental CO2 on plant growth.
  • Discuss greenhouse environmental conditions that warrant supplemental CO2
  • List several different methods of CO2 injection.
One Type of CO2 generator. Image Source: (

non-mineral nutrients
carbon deficiency
carbon dioxide injection
CO2 generator
light sensor
LP gas
natural gas
compensation point


1. Read Chapter 11 in your textbook. Carbon Dioxide Fertilization. pages 387-396.

2. Watch the following slide show reviewing the basics of this topic.

STUDY QUESTIONS and EXERCISES (Answer each of the following in complete sentences. In most cases 2-4 sentences will suffice).
  1. Explain why sufficient carbon dioxide levels are critical to plant growth and development.

  2. If 300 ppm of atmospheric CO2 is sufficient for most plant growth, why is it hypothesized that many plants respond positively to higher levels.

  3. Describe the CO2 compensation points. What is an average level at which greenhouse crops meet the CO2 compensation point?

  4. Explain some measurable benefits of CO2 injection into the greenhouse atmosphere using at least 3 different crop examples.

  5. Describe two different methods of carbon dioxide injection used in greenhouses today.

  6. At Eurofresh Farms (you have seen several videos) they inject CO2 during the day by running the boilers. The hot water generated during the combustion process is then stored and recirculated in the greenhouse during the night. Explain why they go to the additional effort to store the hot water.

  7. Why did using compressed CO2 as a source (which works effectively) fall out of favor and become replaced with injection methods that require combustion?

  8. What are some potential problems that can occur when using combustion as the source of CO2?

I realized last week that I needed to require that your presentations be in PowerPoint or Google Presentations. This is so that they can be shared online with the other online students. The more "traditional" presentation methods are really only an option for the seated class. Please complete your presentation using Google documents or PowerPoint and turn it in. If you need help with this please contact me. I am not grading on technical ability, just information presented.

The presentation does not need to cover every detail from the past four weeks of effort. It should cover the following things:
  1. the environmental production requirements for your plant

  2. how the greenhouse design you came up with is capable of meeting the plant's environmental needs

  3. how your greenhouse design meets any additional requirements for your business plan
For example, a greenhouse designed to produce poinsettias would have to be capable of heating and cooling for the crop, but would look quite different depending on whether the market was retail (out of the same house you grew them in) or wholesale (shipping to retailer).

This exam will be in a familiar format. In order that I have time to grade it, I must receive it by Tuesday December 11th. I will e-mail it with instructions by the end of this week.

Tuesday, November 20, 2007

Exam Study Guide

The Exam Study Guide is now available. Remember the exam is cumulative. More details will be available soon. Until then, have a Happy Thanksgiving.

Monday, November 12, 2007

MODULE 11 - Light and Temperature - DUE. Tues. November 27th.


"Greenhouse growers harness the biology of photosynthesis and flowering to create a marketable product. Like other raw materials needed for plant growth (e.g., plastic, and nutrients), light is not free. We increase light levels by investing in alternative technologies such as state-of-the-art retractable roof greenhouses to maximize available sunlight, or installing high intensity discharge (HID) lights. Alternatively, we may choose to save costs and sacrifice potential yield by using older or simpler greenhouses with lower light transmission. Yet another option is to relocate production (e.g., cuttings or cut flowers) to areas with naturally high sunlight during production months. Light clearly has an economic value.

Growers can benefit from knowing how to best manage light. For example, you may be able to grow an extra production cycle of plugs or bedding plants, hasten flowering of perennials for higher out-of season prices, or make more informed decisions when purchasing new structures and equipment." ---from Lighting Up Profits: Understanding Greenhouse Lighting. 2004. (edited by Fisher and Runkle. ISBN 1-892829-10-X)

  • Explain the basic process of photosynthesis (hopefully this is somewhat of a review)
  • Discuss how light intensity affects growth
  • Describe the possible effects of day length (photoperiod) on the flowering process
  • Compare and contrast different types of supplemental lighting.
  • Explain the methods used to provide artificial long- and short-day conditions


HID lights
black cloth
cellular respiration
fluorescent lights
light quality
incandescent lamps
carbon dioxide
light compensation point
electromagnetic radiation spectrum
light saturation point
visible light
Metal Halide Lamps
inrared radiation
Short-day plants
light meters
Long-day plants

Image Source: Flickr, Bartimaeus


1. Read pages 399 - 431 of the textbook. Chapter 12. Light and Temperature

2. Read parts 1 and 1.1 of the Photosynthesis review on wikipedia.

3. Read the NGMA's Helpful Hints on Supplemental Lighting.

4. Read Evaluating Supplemental Light for Your Greenhouse by Fisher et. al.

5. Watch the following two slideshare shows after reviewing the reading assignments.


PART I. Fill in the blank (2 points each)

1. The process by which green plants convert light energy of the sun into chemical energy is called ________________. (1 pt).

2. The green pigment in the leaf that helps convert the light energy is called ______________. (1 pt)

3. Water used in this conversion process is adsorbed by the roots. The water is the source of the ________________ ions that combine with carbon dioxide to form carbohydrates.

4. Solar energy (light) is transmitted in the form of _________________.

5. Light intensity is measured in units called _____________________.

6. Fluorescent lamps are a better source of light than incandescent lamps because the incandescent lamps give more _________ than light.

7. Excessively high light intensities in the summer may cause __________ of the flowers of chrysanthemums, hydrangeas, and geraniums.

8. Those plants that flower when the day length is longer than a critical number of hours are called _____________- day plants.

9. House plants grown near a window in winter may lean toward the light in response to a reaction called _____________.

10. The light-sensitive substance within plants that responds to day length is a soluble protein called _________.


1. What is the most economical type of lamp used for supplemental greenhouse lighting? Explain why. (10 pts).

2. What is a good rule of thumb for the minimum amount of accumulated PAR that most ornamental crops should receive? (answer should be in micromoles/m2/day). (5 pts).

3. Metal Halide lamps are expensive, but they are occassionally used because of one big advantage. What is this advantage? (5 pts).

4. Which season of the year is it usually most critical to provide supplemental lighting in North America? Why? (10 pts).

5. List at least 5 factors that are important to consider when deciding whether or not add supplemental lighting to a greenhouse production system. Briefly explain why each is important. (10 pts).

6. What are some additional challenges that might arise when supplemental lights are added to a greenhouse production system? In other words what other things will the grower have to adjust for in her/his crop production plan? (10 pts).


1. Based on the graph below answer the following two study questions. Remember your answer must be in %. Show your work. (15 pts). If your HPS lighting system provided 5 mol per day/m2 of PAR and you lived in Columbus, Ohio; What % increase in total light would you receive in January by running the supplemental lighting system? How about in July?

2. Based on the graph below answer the two study questions but for Anchorage instead of Columbus. Show your work (15 pts).

Source: Lighting Up Profits: Understanding Greenhouse Lighting. 2004. (edited by Fisher and Runkle. ISBN 1-892829-10-X)

PART IV. Greenhouse Design Project (Final Assignment Prior to Online Presentation) Complete the assignment in this PDF file.

Monday, November 5, 2007

Module 10 - Alternative Cropping Systems - DUE TUES, NOV 13th.

Hydroponic production of strawberries has many advantages. Could you name a few? (Image Source: USDA)

Up until this point we have focused primarily on 'traditional' greenhouse production. Production that involved horticultural crops being produced mostly in containers using soilless media as a root substrate.

You have been briefly exposed to hydroponic production through the EuroFresh videos, but there are several alternative production systems that are being utilized in commercial greenhouse businesses around the globe.

Some of these systems are even being further adapted by experts for extreme production locations such as the Antarctic, Moon, and Mars! You will see a few images from research in one of the slide presentations. This module will serve as a brief introduction into these systems which are growing in popularity.

  • Briefly summarize three different types of Alternative Crop Production.
  • Compare and contrast NFT with rock wool culture.
  • Describe the function of the Ebb-and-Flood production system.
  • Explain why the invention of Hoagland's solution was a breakthrough in the 1950's.
  • List the advantages of the NFT system.
  • Describe how rock wool is manufactured.
  • List the advantages of rock wool production.
  • Explain how whole firm recirculation can reduce the environmental impact of a greenhouse business.
rock wool culture
gravel culture
sand culture
In-line pasteurization

Simple recirculating plant growth system utilizing materials that could be purchased from hardware and pet stores.

  1. Chapter 10. Alternative Cropping Systems. pages 369-385. In your textbook.
  2. North American Greenhouse Tomatoes Emerge as Major Market Force. A publication by the ERS/USDA.
Review the slide presentations below. The first reviews concepts from the reading. The second introduces you to an integrated agriculture system called aquaponics.

Cartoon of an aeroponic system.

STUDY QUESTIONS (5 pts each, answer in complete sentences)
  1. Compare and contrast NFT with rock wool culture.
  2. Describe three different types of In-Line pasteurization of nutrient solutions.
  3. Briefly describe how rock wool is manufactured. How biodegradable is rock wool?
  4. How does irrigation frequency compare for traditional container systems and rock wool production?
  5. Briefly describe how whole-firm circulation might work for a greenhouse business.
  6. Based on the ERS article what percentage of tomatoes sold in grocery stores in the U.S. were produced in a greenhouse?
  7. What are some of the growing pains faced by the North American Greenhouse Tomato industry?
  8. A local greenhouse grower says that he can get ten times the yield of tomatoes from his greenhouse using the same amount of space as his competitor that grows field-grown tomatoes. Do you believe the grower or is this just hype? Support your answer.
  9. What North American country has the fastest growing production of greenhouse tomatoes and why?
  10. What North American country has seen a decline in greenhouse tomato production and why?
Continue with your greenhouse design project. Remember to contact your instructor if you have questions. The next assignment is available in PDF format here.

Monday, October 29, 2007

MODULE 9 - Next Step in the Greenhouse Exercise - DUE Tues. NOV 6th

Hi all,

As some of you know, I am teaching a seated section of this course this semester as well. The seated course has fallen about a week behind the online section. In order to re-synchronize the courses, the distance learners get a light week. You only need to complete Part II of the greenhouse assignment this week. You may mail the assignment to me if it is easier to handle the calculations that way. Just make sure it is postmarked by November 6th.

Let me know if you have any questions,


Tuesday, October 23, 2007

Module 8 - Fertilization, DUE Oct. 30th, 2007

Boron Deficiency on Hydroponically Produced Melon.

Fresh plant material is usually made up of between 80 and 95% water. So far, 16 elements have been identified as essential for plant growth. The plant cannot complete its life cycle without the element. Action of the element must be specific - no other element can take its place. The element must be directly involved (structure, constituent, enzyme activator, etc.)

Optimum plant growth is a function of nutrient concentration in the plant. There is a critical nutrient concentration below which growth is reduced/terminated. The adequate zone is above the critical concentration and provides maximum growth. The toxic zone is above the adequate zone, again resulting in reduced growth or death. THEREFORE, MORE IS NOT ALWAYS BETTER!

---Dr. Pat A. Rorabaugh, Controlled Environment Agricultural Center, Department of Plant Science, University of Arizona

  • List the major and trace elements needed for plant growth
  • Recognize common symptoms of essential element deficiencies
  • Evaluate deficiency symptoms to determine if the element is mobile or immobile
  • Explain the importance of pH in terms of nutrient availability.
  • Explain how soluble salts can be used to infer nutrient concentrations from a media solution
  • List and describe the general forms of fertilizers.
  • Explain the advantages of chelated micronutrients
nonfertilizer (non-mineral) nutrients
primary macronutrient
secondary macronutrient
pre-plant fertilization
post-plant fertilization
rule of 75
backflow preventer
liming materials
dolomitic limestone
sulfur, iron sulfate, aluminum sulfate
slow-release fertilizer
polymer encapsulated fertilizers
slowly soluble fertilizers
sulfur-coated fertilizer
chelated micronutrients
PourThru method
Press Extraction method
Foliar analysis

  1. Read Chapter 9 in your textbook. pages 303-366; this chapter is a long and detailed, so allow yourself extra time to complete the reading.
  1. Watch all the videos at the end of this section, you have seen a couple of these before. (THERE IS NO AUDIO LECTURE THIS WEEK because I think the growers tell this story best).

  2. Compare and contrast the plant nutrition program of Eurofresh, Kraft Farm, and Crossroad Farm in a few paragraphs. (20 pts).

  3. Choose the nutrition system from the greenhouse operation you liked best. Explain what it is about their nutrition plan that appeals to you in 4-6 answers. Back up your choice with information you have learned from the course. (10 pts). There is no right or wrong choice here. All these growers or businesses were selected for their knowledge and economically successful operations.

STUDY QUESTIONS (2 pts each)
  1. What is the purpose of a back flow preventer.

  2. Which essential elements come from the air and water?

  3. Explain what essential nutrients (elements) are impacted by the Cation Exchange Capacity of a soilless media.

  4. What essential nutrients are usually available in anionic forms that are easily washed out of the root substrate along with excess water?

  5. Explain the differences in nutrient availability caused by pH in soil and soilless media

  6. A purple color on the underside of the seedling leaves of marigolds and tomatoes is a sign of what two production problems.

  7. Describe the difference between a slow release fertilizer and a slowly soluble fertilizer.

  8. Name the essential nutrient at the center of every chlorophyll molecule.

  9. Fluorinated water can be a problem if you are producing members of a certain plant family. What is that family? You are probably very familiar with the ornamental members of this family. For extra credit name a commercially important vegetable crop member of this plant family that is sensitive to Fluorine.

  10. A petunia grower notices some purple discoloration on the underside of older leaves. Some leaves are brown and papery. What nutrient is likely deficient?

  11. The new buds of petunia plants are dying, but the new leaves near the bud look green and healthy although slightly misshapen. What nutrient is likely deficient?

  12. A petunia grower notices interveinal chlorosis on newly emerging leaves. What nutrient is likely deficient?

NEW THIS WEEK ONGOING Greenhouse Design Project (46 points). There will be new components of this project due each week. You can print off the handout for week one in PDF format here. NOTE: for 1.b. The hard copies will help you later on. You can turn in the links on your homework assignment.

Greenhouse Image by Kamoda (Japan)

Monday, October 8, 2007

Module 7 - Watering (Irrigation) DUE Tuesday, Oct. 23

Automatic Irrigation System for Hanging Baskets

This module consists of three subject areas that overlap. First, by reading the textbook you should develop an understanding of the importance of irrigation and the biological functions that water drives in plant growth and development.

Second, you will take a look at the many different types of irrigation systems that are now available for greenhouse growers to choose from. These range from the trusty watering wand to high-tech automated watering systems like the one shown in the image here that combines a hanging basket conveyor with a two tiered water water delivery system.

Finally, you will examine the impact of automation on the greenhouse industry.

  • Explain why a plant needs water
  • Understand how water is taken up and moved through plant structures
  • List the effects of too much water on the growth of plants
  • Discuss how moisture stress affects plants
  • Describe several ways that water may be applied to crops
  • Discuss the current trends in greenhouse automation and speculate on what the future may hold.
Ebb and Flow benches can help reduce foliar diseases, but create other management issues.

reverse osmosis
Moisture Probes
hard water
hose watering
softened water
low volume watering
acidifying water
trickle irrigation
drip tube
moisture stress
spray stakes
wetting agents
soluble salts
boom irrigation
ebb and flood irrigation
capillary mat

  1. Read Chapter 8: Watering in your text. pages 257-301
Ebb and Flow system adapted to the entire floor of a greenhouse.

  1. Watch Audio PowerPoint Lecture on Greenhouse Irrigation (approx. 40 minutes). Depending on your Internet Connection Speed this may take some time to download.

  2. Search the Digital Greenhouse Repository using the keyword "irrigation"; study the pictures and read the abstracts when available.

  3. Watch the short video clips showing automated hanging basket and boom irrigation on display at a trade show. Write a paragraph explaining how these systems would not only save labor but could improve plant uniformity, quality, and health. (20 pts).

  4. Briefly explain (based on plant biology) why transpiration rate directly correlates with the rate of photosynthesis in a plant. (10 pts). You may have to do a little searching to answer this one.

  5. Choose 5 "irrigation" images from your search in #2 that show 5 different irrigation methods/systems and describe the advantages and disadvantages of each one. (20 pts). Create a new Google Document Presentation to answer this question. (It's like using PowerPoint, contact your instructor if you need assistance)
Poinsettias on sale in a small-scale production/retail center. Note all the drip tubes, during peak production times there are just as many poinsettias hanging from the frame as are on the benches.

STUDY QUESTIONS (Answer in complete sentences)
  1. Discuss the three rules of irrigation as covered in your textbook. For each rule explain its significance and give an example of what can go wrong if the rule is not followed (10 pts).

  2. Compare and contrast pH and alkalinity. Which is arguably more important for greenhouse crop production? Give two examples of how alkalinity and pH can interact to present special challenges for greenhouse crop production. What corrective steps can be taken to correct for water with high alkalinity? (10 pts)

  3. What is water harness actually a measure of? How does water hardness come into play when trying to maintain the proper balance between calcium and magnesium? What are some general rules of thumb to maintain the balance between these two nutrients? (10 pts)

  4. Compare and contrast 3 different containerized plant watering systems (you can choose). Make sure you indicate the advantages and disadvantages of each. (10 pts)

  5. Some growers insist on hand watering to save costs and maintain irrigation control. Support or argue against this practice with information you learned during this module. (10 pts).
Extra Credit (5 pts). Develop a summer and winter production calendar (dates to transplant) for the hydroponic lettuce system highlighted in the video below.


I sent out the exams today. Please read the e-mail and contact me if you have any questions.



Monday, October 1, 2007


No new module this week. Exam one will be e-mailed directly to your google account on or before October 9th and be due October 16th. Fall Break is week of October 15th, so your next module won't be due until October 23rd.

So study and then enjoy a short break!

Monday, September 17, 2007

MODULE 6 - Root Substrate and Root Substrate Pasteurization - DUE Tues, Oct. 2nd

Vermiculite, Pine Bark, Perlite, and Sand.

In the past soil or soil mixes were commonly used in greenhouse production. However, the difficulty, expense, and sustainability issues of dealing with soil have lead to the almost exclusive use of soilless media mixes for greenhouse production. There are some important exceptions such as organic in-ground tomato production and cut flower production, but in general if you go to work for a greenhouse you can expect to see soilless media being used. Soilless mixes are more uniform, lighter to ship, and perhaps most importantly sterile and free of disease. This module introduces you to different types of media that are used in greenhouse production both current and historical. You will also learn about the properties of this media. This module requires mostly reading and learning some new vocabulary. It is relatively short, but will build the foundation required for some more intense modules in upcoming weeks.

  • Describe the uses of soil and soilless media in the greenhouse industry
  • Review proportions of solids, water, and gases in soils
  • List the functions of soilless media an soil used as root substrates
  • List and describe the common materials used to produce soilless media
  • Familiarize yourself with the vocabulary of root substrates
hardwood bark
softwood bark
plant nutrients
growing medium
peat moss
sphagnum moss peat
peat bogs
rock wool
fine texture
C:N Ratio
bulk density
polystyrene foam
medium texture
coarse texture

  1. Chapter 6. Root Substrate. pages 197-236

  2. Chapter 7. Root Substrate Pasteurization. pages 237-256

  3. Review Media (PDF of PPT) File from Colorado State (this will be a good review AFTER reading the chapter)

  1. Review Slide Show Introducing Root Substrates (shown below)

  2. Go to the Greenhouse Digital Repository and search the images using 'Root Substrate', choose 5 images of interest to you and describe how the image relates to the material covered in this module. (20 pts)

  1. What are the functions of any root substrate? (soil-based or soilless) (4 pts).

  2. Why are soil-based root-substrates rarely used in the greenhouse industry today? (6 pts, answer in complete sentences)

  3. Explain in your own words how root substrate texture is related to plant water availability and aeration (6 pts, answer in complete sentences).

  4. In number 3, how does the relationship you describe manifest itself into greenhouse management where different sizes and shapes of pots must often be used. (4 pts)

  5. Design a table of desirable root substrate properties. For each property describe the optimum condition and quantitative recommendations when available (i.e., in the case of pH give a common recommended range of values) (15 pts, you can create a table or create a spreadsheet for this exercise).

  6. Based on available water alone which root substrate would be the best for a greenhouse crop and which would be the least preferable? (4 pts, Table 6-1 of textbook).

  7. Produce a graph of %Water and %Air available in 8,6, and 4 inch pots filled with a media made from 1 peat moss: 1 vermiculite (Table 6-2). What physiological process can be impacted by decreased air availability to the roots. (10 pts)

  8. In the first video following the questions the business produces all their own media. What are some of the challenges associated with custom producing your own root substrate? (6 pts)

  9. In the second video, a greenhouse tomato producer uses compost as a regular amendment. What are some benefits and potential hazards of this practice? (5 pts)

  10. Discuss reasons why coir use in the greenhouse industry has increased greatly in recent years. (Answer in complete sentences, 5 pts).

  11. You are growing 5,000 poinsettias for the holiday market. You are producing 'Prestige Red' in 6" standards. How many cubic feet of media will be required? (5 pts, show your work).

  12. In a special native plant project you have made the highly unusual decision to use soil. You heat the soil up to 185 F, but are still having unacceptable losses due to disease. Hypothesize what your problem might be. (5 pts).

  13. Methyl bromide at one time was the chemical pasteurization agent of choice. Explain why its used is being phased out and discuss some alternatives (5 pts).
Locate a picture of an automated root substrate process utilized in the greenhouse industry. Briefly describe how this could be of economic benefit to the business using it.

Monday, September 10, 2007

MODULE 5 - Environmental Controls and Basic Plant Biology - Due Tuesday, September 25th

Tomatoes being produced in a simple, but profitable High Tunnel. Dr. Lewis Jett is an expert on these types of 'greenhouses'.

This week's module covers the short Environmental Control Chapter in your textbook and a short review of plant biology. This course has no prerequisites, so this review needs to happen somewhere. Hopefully, it will be a review for some of you.

The greenhouse environment is a highly variable one. The level of environmental control is also quite variable. Ranging from the basic control provided by passively ventillating "high tunnels" to banks of computers managing everything from active cooling, heating, CO2, HAF fans, irrigation, and fertilization (like you might see in an operation the magnitude of Eurofresh Farms, Inc.) It is important to realize that what the greenhouse grower is striving to do is use the available environmental controls to maximize plant growth towards horticultural goals.

A high tunnel operator may strive to have organic late season tomatoes available. The growers customers may tolerate certain size variation and blemish issues in order to by an organic product locally. However, an organization like Eurofresh may use every environmental control manipulation at their disposal to produce a uniform high quality blemish free tomato at the same stage of ripeness. They may have a delivery wholesale target price and volume that they are contracted to meet. In both cases the individuals in charge of growing plants are manipulating the environment to achieve certain results in plant growth.

In order to understand fully the role that environmental control plays in plant development one must have a good foundation in plant biology. There are entire degrees offerred in plant biology, so the task of packaging this into a single module is relatively daunting. I have tried to boil down some of the most important factors from your reading, but in order to master this subject you will have to do substantially more reading in the future.

Differentiate between manual controls, step controllers, and automated environmental control
Discuss the advantage of integrated control
Briefly Describe the future of Model-based control
Be able to draw and label a typical plant cell
Learn the differences between meristematic and permanent tissues
ID the various parts of a leaf
ID the various parts of a complete flower

manual controls
on/off switch
dedicated microprocessors
Integrated control
model-based control
primary walls
guard cells
cambial meristem
intercalary meristem
pallisade layer
root hairs


  1. Read Chapter 5. Environmental Control Systems in text. (pgs. 185-196)

  2. Watch Slide show on Environmental Controls. Watch two Eurofresh videos on structure and computers.

  3. Review Animation: Flower anatomy (200.498 Kb)

  4. Review Animation: Plant Transpiration Process (371.266 Kb)

  5. Review Animation: Water and nutrient uptake by roots (168.561 Kb)

  6. Review the components of the plant cell at Cells Alive. It will help you answer the study questions.

  7. If you need a basic review you can try this set of HTML pages on the plant Cell from Wellesley College.

  8. For an excellent review of leaf anatomy and leaf tissue organization review the following page and links at the Molecular Expressions Website.

  9. You should be able to label the basic parts of a plant cell, leaf cross section, and flower.
The animations above were made possible for educational use through the Plant and Soil Sciences eLibrary. Please see credits under each animation for further information.

Short essay (answer in complete sentences)
  1. Compare and contrast on/off switches and step controllers. (10 pts).

  2. What are the advantages of integrated control using computers. Why do you think there are still so many growers who don't use integrated control? (20 pts)

  3. Watch the Eurofresh video on structure again. Summarize how computerized environmental control is so critical to their operation. How do you think computer use has made them more profitable. (15 pts)

  4. Briefly describe the evolution of environmental control in greenhouses. (15 pts)

  5. Describe where a "Speaking Plant fits into the evoloution of computer control (6 pts).

Fill in the blank (2 pts each)
  1. The aboveground light absorbing system of plants is made up of primarily_______________ and sometimes___________________.

  2. The basic units of which all plants and animals are made are ______________.

  3. The small bodies within the cell tha contain cholorphyll are called ______________.

  4. Large groups of cells that act together to perform the same function are known as ______________.

  5. Apical meristems are responsible for an increase in the _____________ of a stem.

  6. The epidermis of the root provides _____________ for the inner plant cells.

  7. A group of cells at the tip of a root is called the root ____________.

  8. Most of the absorption of water and nutrients takes place through the ___________.

  9. Water moves from the roots to the leaves through the vascular tissue called the ____________.

  10. The other vascular tissue is called the ______________.

  11. The point at which a plant will no longer recover from a lack of water is known as the _____________ point.

  12. The process of photosynthesis occurs mainly in the leaf ________________.

  13. A bud that grows in the angle between the petiole and the main stem is called an ___________ bud.

  14. Pores or openings in the leaf where gas exchange takes place from the outer air to the intercellular leaf spaces are called _____________.

  15. The male parts of the flower are a slender stalk called the _______________ and the enlarged part at the end called the ______________ where pollen grains are formed.

  16. The female parts of a flower are the ______________, ________________, and _______________.

  17. The showy, colorful parts of the poinsettia are called ___________

Sunday, September 2, 2007

MODULE 4 - Greenhouse Cooling - DUE Tues. Sept. 18th.

Image Source: Munter's

One of the first considerations for greenhouse cooling is to decide what you will be growing. The necessity for greenhouse cooling may increase depending on the things you plan to grow. Once your greenhouse temperature exceeds 85 degrees F, some plants may be stressed from the excessive heat. Your greenhouse cooling requirements may also depend on the climate you live in. If you live in a cooler climate you may not have a concern with greenhouse cooling until summer arrives. (from The Greenhouse Catalog)

  • Review the basic principles of greenhouse ventilation and cooling.
  • Discuss advantages and disadvantages of different cooling systems
fan and pad
passive cooling
active cooling
winter cooling
summer cooling
Chlorine/Bromine injector
relative humidity
sling psychrometer
light intensity
temperature gradient
exhaust fan

  1. Explain why disease incidence may be higher in a greenhouse with a pad-and-fan cooling system than one with fog cooling? (5 pts)

  2. Why is necessary to have a convection tube for air distribution for active winter cooling systems where you plan to use the cooler outside air on those sunny bright winter days? (5 pts)

  3. When the area of cooling pads needed is calculated by a greenhouse designer the thickness of the cooling pad to be used is important to know. For example when a 6" pad is used only 66% of the total square footage of pads is needed as when 4" thick pads are used. Why is this the case? (5 pts)

  4. How do HAF fans assist with active winter cooling? (5 pts)

  5. Describe the major components of a pad-and-fan cooling system and explain the role of each. (15 pts)

  6. Why is a chlorine/bromine injector important to maximize the functional life of the cooling pads? (5 pts)

  7. Why is water quality much more critical in a fog cooling system than in a pad-and-fan cooling system? (5 pts)

  8. One future system that engineers have suggested would be spraying fog directly into existing pads in pad-and-fan systems. What parts of the system you described in question 5 might you be able to eliminate? (5 pts). Do you think this would eliminate the temperature gradient that exists with current pad-and-fan cooling systems? (5 pts).

  9. Conditions for workers are of greater concern now than ever before. What are two advantages of fog cooling systems for employees that spend long hours in the greenhouse? (10 pts).
Watch Microlecture Cooling 1 Now
Watch Microlecture Cooling 2 Now
  • Watch both microlectures.

  • Review calculations for greenhouse cooling on your own. I expect you to know what factors are important and why? For example the role that light intensity, elevation, and allowable temperature rise play in the greenhouse, but you will not be responsible for the direct calculation in this course.

  • Go to the following website and determine the wetbulb temperature for the following scenarios: (TWB = Wetbulb Temperature at the website) You will have to convert between metric and English units is a great site you should bookmark.
Location, Dry Bulb Temp (F), RH
Tucson, AZ 98 F, 27
Clyde, NC 92 F, 59
Fort Pierce, FL 84 F, 77

Based on what you learned in the microlectures answer the following questions based on the above scenario for July 28th, 2007:
  1. What is the wetbulb temperature for the given dry bulb temperture and RH at each location? (15 points)

  2. If the same greenhouse was constructed at all 3 locations which one could achieve the lowest tempterature given the scenario above if the greenhouses were equipped with pad-and-fan cooling (5 pts).

  3. What would be the lowest temperature possible for the clyde location on this day (correct for pad-and-fan) system? (5 pts)

  4. What would be the lowest temperature possible for the Clyde location and scenario if a fog cooling system was installed? (5 pts)

  5. Explain why the lowest temperature possible at the Fort Pierce and Clyde locations is essentially the same on this particular day with these conditions? Afterall it is 8 F cooler in Fort Pierce due to Ocean breezes. (5 pts)
Switching careers is never easy. See the road one grower took. Watch the 'Starting A New Business'

Thursday, August 30, 2007

3-Week Course Evaluation

We want HCC's distance learning courses to be the best they can be. Your early feedback will help us reach that goal. Please take a few minutes to complete a brief evaluation of this course. You will have until 11 p.m. Friday, September 7 to complete the evaluation.

To evaluate this course, click here and enter the following 3-digit PIN where prompted: 778

Please note that all evaluations are processed by the College's Office of Research and Institutional Effectiveness. Your responses and comments are anonymous and your instructor will only receive summarized results at the end of the evaluation period. We appreciate you taking a few minutes to provide a frank and honest evaluation of your course.

Jonathan Vester, Coordinator of Research and Institutional Effectiveness

Wednesday, August 29, 2007

Module 3 - Greenhouse Heating - DUE Tuesday, September 11th


Effective and economical greenhouse heating is the union of an appropriate heat source and an efficient heat distribution system. The best greenhouse heat source in the world is useless if the heat cannot be transferred to the plant environment. Likewise, an efficient heat distribution system is useless if an adequate heat source is not used. The most efficient greenhouse heat source and the most efficient heat distribution system can continue to work well -- only when properly maintained.


* Evaluate the strengths and weaknesses of different types of heating systems
* Calculate the heating requirements for a greenhouse.
* Operate greenhouse heating systems in a safe manner.
* List standard maintenance requirements of greenhouse heating systems.


greenhouse effect
solar heat
radiant energy
LP gas
solar energy
perforated polyethylene tubing
natural gas
horizontal unit heater
central heat
a^2 + b^2 = c^2
aspirated thermostat
area of a right triangle = 1/2bh
finned pipe
zoned heating
unit steam heater
carbon monoxide
heat exchanger
sulfur dioxide


NGMA Heating Tips (75.094 Kb)

1. Read pages 93-159 of the textbook.

2. Read NGMA helpful heating tips (link above3).


1. Watch heating slide show embedded in blog post.

2. Watch the Crossroads Farm (VT) 'Heater Problem' video. Describe what happened to Tim and Janet Taylor when they expanded their greenhouse. (5 pts)

3. Submit use the internet to determine what the record low is for each month where you live (you may need to use a town near you if you live in a rural area). HINT: The Weather Channel has such records available for public viewing. (5 pts)

4. Use the Virtual greenhouse to run the following three simulations (don't adjust any additional settings that will come later):

* Burlington, VT; Winter; double poly, quonset style house, no heater, with set points.
* Burlington, VT; Winter; double poly, quonset style house, 1 heater, with set points.
* Burlington, VT; Winter; double poly, quonset style house, 2 heater, with set points.

Describe what happens in each setting. Make sure you pay close attention to the y-axis on the Air temperature graph. (10 pts)


1. Compare and contrast unit heaters and boilers. Explain the advantages and disadvantages and what types of operations might use both. (10 pts.)

2. Unit heaters are very common with growers who have relatively small amounts of production space. However safety is always an issue. (10 pts)

a. describe the appropriate positioning of the exhaust pipe.
b. why does a grower have to insure a constant source of fresh air when the heater is running.
c. what are two potential byproducts of a poorly functioning heater that are damaging to plants
d. what is a byproduct that can be extremely dangerous to humans
e. What must you do first if you get an alarm in the winter that a heater is off in your ornamental greenhouse?

3. Explain the advantages of an infrared heating system. (5 pts).

4. You have a single a-frame greenhouse with the following dimensions. (You may want to start by drawing yourself a picture). The dimensions are 50 ft (length) X 24 ft (width) X 8 ft (eave height). The ridge is 19 ft high. The glazing material is twin-wall polycarbonate. You want to be able to hold an inside temperature of 55 F even when the temperature outside is 0 F and winds are 20 mph There is no curtain wall. (25 pts)

a. calculate the heat loss/hr (show all your work. HINT: you may want to work through the problem on pages 137-139 STEP-by-STEP. USE THE SAME STEPS FOR THIS PROBLEM. (call me if you have difficulty we will work through it together). If you have difficulty showing the math on Google Documents you can mail me hand written sheets, just make sure they are postmarked by the module due dates.

b. search the internet and locate a unit heater(s) that will supply the amount of heat you calculated. Explain your choice. Don't worry about brand names and cost just BTU output. Please put the website in your answer so that I can check it.

5. You have a gutter connected a-frame (each bay roof) greenhouse with 3 bays and the following dimensions. (You may want to start by drawing yourself a picture). The dimensions are 100 ft (length) X 72 ft (width, each bay is 24 ft in width) X 20 ft (eave height). The ridge at the center of each bay is 26 ft high. You want to be able to hold an inside temperature of 55 F even when the temperature outside is -10 F. The material covering this metal greenhouse is single pane glass. Your greenhouse happens to be located in a very windy area. So count on 35 mph winds on this -10 F winter night you are planning for. (30 pts).

a. calculate the heat loss/hr (show your work)

b. you have decided to have a boiler installed and you will use 2" iron plain pipe (no fins) to deliver the heat to your greenhouse. How many feet of pipe will you need to deliver the amount of heat required on the cold night that you designed the heating system for? How many feet will you need of finned pipe? (see page 79 in your text for a hint).


I was fascinated by this greenhouse gallery. The ingenuity these people displayed in creating their own local controlled environments was awesome. Most folks were novices. Imagine what you will be able to accomplish once you have successfully completed the course. Imagination + Knowledge = Success

Friday, August 17, 2007

Turning in Assignments

Make sure you have turned in your HOP Assignment. All students must turn in the HOP Assignment by August 24th or they will be dropped from the course.

If you have turned in your HOP Assignment you be wondering how you will turn in other assignments. Below is a video to help get you started. I know it is a bit fuzzy, but watch the mouse pointer and try to create a document on your own e-mail account. Please contact me if you have any questions. I would be happy to help out. MODULE 1 is due August 28th by midnight.

Friday, August 10, 2007


Lettuce seedlings at Epcot. Image Source: sylvar

Welcome to Fall Semester 2007 at Haywood Community College. You are enrolled in the online section of HOR 134 Greenhouse Operations. I hope you find this material as exciting as I do. Understanding the fundamental principles of greenhouse operations will help you produce floriculture crops more efficiently and economically.

Please take time to familiarize yourself with the Blogger Environment. If you are new to Blogger an easy way to start is by following all the links in the Course Menu at the right. Also be sure to read the announcement concerning the HOP Assignment. The HOP Assignment must be completed by August 24th or you will be dropped from the course. This is a simple assignment that serves as a record of you having signed onto the course.

Please also read the syllabus thoroughly. If you have any questions please contact me. I would be happy to answer them. My physical office is at Haywood Community College in 1105 at the Nix Horticulture Complex. My office phone is 828-565-4275. The e-mail I want you to use to contact me is .

Make sure you sign up for a free gmail account at I will be using this e-mail to contact you and we will be using other google applications during the semester.

Thank you for your interest in horticulture technology and I look forward to a successful course this semester. I am always happy to assist students, so if you have any questions, concerns or constructive criticism please contact me.

Thursday, August 9, 2007


In order to remain enrolled in your online classes, you must complete the Haywood Online Prep (HOP) assignment for each course you are registered to take. Students who have not "hopped" by 4:00 p.m. Friday, August 24, 2007 will be marked as a "no show" and dropped from the course.

  1. Go to and sign up for a free google account. This will be the e-mail you use exclusively for this course.

  2. Place your cursor over this link and click your right mouse button. A pop-up menu will appear.

  3. Choose the Save Target As option (Save Link As in Firefox).

  4. In the Save in box, select the location where you wish to save the document on your computer.

  5. In the File name box, change the file name to your full name.

  6. In the Save as type box, verify that the file type is Rich Text Format.

  7. Open the HOP Assignment file on your computer using your word processing program.

  8. Type your answers to the eight (8) questions in the file. Be sure to Save the changes.

  9. After you complete the work, log into your Gmail account and send an e-mail to me ( with the RTF file you created as an attachment.

When your instructor acknowledges receipt of your file, a check mark will appear next to your name in the online gradebook.

* A file saved in Rich Text Format (RTF) is a text file that contains formatting instructions that most word processing software applications can understand. Saving files in this format ensures that your instructor can open your assignments even if he or she uses a different word processing program. For help saving files in Rich Text Format, click here.

Image Source: SC Fiasco

Module 2 - Greenhouse Construction - DUE SEPTEMBER 4th.

In many cases students will be planning to construct new greenhouses or purchases existing greenhouses when considering a new horticulture business venture. One often overlooked process is the planning involved with site selection.

There are many decisions to made in a business plan prior to the construction or purchase of a greenhouse. These are critical to economic success. I have met more than one gifted enthusiastic horticulturalist that met economic hardship by diving headlong into production without first spending the necessary time to come up with a thoughtful business plan.

New greenhouse construction in Chicago, IL. Image Source: clare and ben

Choosing the type of greenhouse you need for production is a complicated process. Sometimes a simple structure will suffice and may result in positive economic returns. Other times labor costs combined with a target wholesale market may be decision drivers in choosing a more complex structure such as that shown in the image above. This house below is a high profile gutter-connected range. Sometimes rolling benches are added to further maximize the utilization of light for crop production.

Large glass greenhouse range in Holland. Image Source: akbar1947.

  • Understand the importance of a business plan prior to making any decisions involving greenhouse operations or management.
  • List what decisions have to be made before the greenhouse business plan can begin.
  • List and explain a dozen factors that are integral to greenhouse site selection.
  • Be able to recognize and name different types of greenhouse structures.
  • Identify the various components of a greenhouse.
  • Discuss the advantages and disadvantages of different types of glzing materials.
  • Discuss economic factors to consider when constructing a greenhouse.

growing period
growing media
annual production
marketing system
investement capital
property value
labor law
H2A Visa
building code
low tunnel
high tunnel
water quality
gutter connected
high profile
snow fence
low profile
safety glass
plastic resins
gutter connected
bench washing machines
even span
uneven span
float glass
tempered glass
ebb and flow
bar cap
rolling benches
galvanized metal
expanded metal

  1. Read summary of Greenhouse Construction from WSU as a primer.
  2. Read Chapter 2 in your textbook. pgs. 41-90
  1. Watch the Site Selection microlecture. This mini-presentation is about 22 minutes, so depending on your Internet Connection Speed it could take anywhere from 5 to 50 minutes to download. I would start the download process and then read your texbook while you wait.

  2. Watch the Greenhouse Construction microlecture. This presentation will walk you through the basics of greenhouse construction to supplement your textbook reading.

  3. Watch the Greenhouse Glazing microlecture. This presentation will help you review the material covered in the text.

  4. Watch the Greenhouse Benching microlecture. This lecture covers the variety of benching material that you may find in the world of greenhouse operations.

  5. Watch the structure videos from each of the greenhouse locations we will be highlighting this semester. (at the bottom of this section)

  6. Watch the video from Kraft Gardens in Florida entitled "Building for Hurricanes." (Below)

  7. Review greenhouse construction by viewing the following slides.

  8. Last week you were asked to visit a greenhouse and take some pictures (if you have access to a camera...don't worry about images if you don't have a camera). Please post the name and location of the greenhouse you visited to the discussion board. In additional include the following on the discussion board: Briefly describe the business (i.e. wholesale, retail, bedding plants, mass market, specialty, etc.) Briefly describe some of the site characteristics. What do you think worked about the layout of the greenhouse or greenhouse range? Was there anything you might change? (10 pts)


I. Organic University: Greenhouses for year-round food and farming Part 1: Greenhouse site selection Before you get there, you need to know just where you?re growing. By Katie Olender

A good review of some major site selection factors for those interested in organic food production in greenhouses.

II. Selecting and Building a Commercial Greenhouse

By John W. Bartok, Jr., Agricultural Engineer at the U. Mass Amherst.

A great review of all major site selection factors. This is the reference that much of the microlecture is based on.

III. Sample Manufacturer Brochure on Greenhouse Design and Overcoming Site Selection Difficulties.


STUDY QUESTIONS (Answer in Complete Sentences)
  1. for the purposes of this question imagine that you are going to start a new greenhouse business at your current place of residence. In this imaginary scenario the area of land you have is not limiting nor is capital for investment. (10 pts)
    • Discuss the Environmental, Land, and Resource Considerations for your site.
    • Do you think your site would be more suitable for a retail or wholesale business? Explain why.
    • What do you think the most limiting factor would be at your site? There is no right or wrong here, but explain the reasoning that lead you to your answer.

  2. Which side of a greenhouse should the headhouse be located on? Why? (10 pts)

  3. How is producing plants different from a manufacturing business such as making furniture? What are some similarities? (5 pts)

  4. List three federal government offices that have free information available that would assist in site selection for a new greenhouse. (5 pts)

  5. Compare and contrast 3 different types of greenhouse glazing materials that are commonly found commercially. Be sure to thoroughly cover the strengths and weaknesses of each. (10 pts)

  6. Describe the strengths and weaknesses of wood framed greenhouses as compared to metal framed greenhouses. (5 pts)

  7. What are the advantages of a high profile greenhouse? low profile greenhouse? sawtooth style house? (5 pts)

  8. What is the primary advantage of a gutter connected greenhouse? (5 pts)

  9. Describe 3 different types of benching. (5 pts)

  10. Describe important considerations for greenhouse directional orientation. (10 pts).

  11. What are some of the special features of the Florida greenhouse in the video that allow it better withstand damage from hurricanes? (10 pts)

  12. In what situations do you think a glass covered greenhouse would be appropriate? Are there situations where double poly might be preferred? (10 pts)

Wednesday, August 8, 2007

Module 1 - Greenhouse Industry Introduction - DUE AUGUST 29th

Over the past decade, floriculture and nursery crops have been one of the fastest growing U.S. agricultural sectors. Of the estimated $45 billion in U.S. horticulture sales in 2003, floral and nursery crops contributed a third, or $15 billion, less than vegetables' sales receipts of $17 billion, but more than fruits and nuts' $13 billion. ERS analyzes conditions and trends that influence supply, demand, trade, and prices in the domestic floriculture and nursery markets. -ERS 2006

It is important to remember that overall trends are based on regional components. A bright outlook for the industry as a whole may not translate to every greenhouse production area in the United States.


  • List and Describe the areas of major greenhouse flower and food crop production in the United States.
  • List the ten highest value florist crops.
  • List the top 5 states in floriculture production.
  • Explain why tomato producers located in Mexico may be increasingly competitive with greenhouse tomato producers in the United States.
  • List 8 sources of recent greenhouse horticulture information.
Floriculture Agricultural Research Service National Agricultural Statistics Service
green plants American Society for Horticultural Science
flowering pot plants FloraCulture International
bedding plants International Association of Horticultural Producers
foliage plants Greenhouse Business Magazine
cut flowers Greenhouse Grower Magazine
annuals The Green Beam
perennials Greenhouse Product News
USDA/ ERS Grower Talks Magazine

Green Profit Blog

2006 Floriculture and Nursery Crops Yearbook (661.938 Kb)
  1. Read pages 1-10 of the Floriculture and Nursery Crops YEARBOOK published by the ERS/USDA.
  2. Familiarize yourself with the latest published Statistics on the Industry in the United States.
  3. Read Chapter 1 in your textbook. Floriculture a Global Industry. pages. 1-38. (We won't spend a lot of time on this, but this is useful information to know).

Watch the following videos.

Visit a local greenhouse and be prepared to answer some questions concerning your visit. If you have a digital camera take some pictures of your visit (always ask the manager/owner for permission prior to taking any photos).

STUDY QUESTIONS (Answer in complete sentences)
  1. What are the top five floriculture crops produced in the United States? (10 pts)

  2. What are the top five floriculture production states? (10 pts)

  3. What are some of the advantages that growers have in California and Florida that make their greenhouse industries so large? Despite these advantages why are so many companies moving some of their operations off-shore (for example Ecke). (10 pts)

  4. Theoretically, why would the USDA be a better source of factual information than a trade journal? Why would I use the word theoretically in the previous question? (10 pts)

  5. Differentiate between the greenhouse industry in Florida and California as introduced in the videos (20 pts) You will have to search the web for information regarding the California industry. The USDA ERS is a good place to start.

  6. Differentiate between the greenhouse industry in Ohio and Vermont as covered in the videos (20 pts)

  7. Why is it important to get the most recent news and be involved in the professional organizations of your chosen field of study? (10 pts)

  8. Describe one greenhouse related horticulture career that you find interesting (10 pts).
List of links on Horticulture Careers


Watch this videos to get a better feel for the types of work that greenhouse and nursery managers conduct on a daily basis.