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

INTRODUCTION

"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)

LEARNING OBJECTIVES

• 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

TERMS TO KNOW

photosynthesis
HID lights
black cloth
cellular respiration
fluorescent lights
light quality
chlorophyll
incandescent lamps
phytochrome
carbon dioxide
light compensation point
germination
electromagnetic radiation spectrum
light saturation point
LPS
visible light
phototropism
HPS
PAR
photoperiod
Metal Halide Lamps
inrared radiation
quinox
lumens
Short-day plants
light meters
Long-day plants

Image Source: Flickr, Bartimaeus

READING ASSIGNMENT and ACTIVE LEARNING EXERCISES

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.

| View | Upload your own

| View | Upload your own

STUDY QUESTIONS

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 _________.

PART II.

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).

PART III.

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.

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

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

INTRODUCTION
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.

LEARNING OBJECTIVES

• 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.

TERMS-TO-KNOW
nutriculture
hydroponics
NFT
rock wool culture
whole-firm-recirculation
ebb-and-flood
gravel culture
sand culture
In-line pasteurization
aquaponics

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

READING ASSIGNMENT

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.

ACTIVE LEARNING EXERCISES
Review the slide presentations below. The first reviews concepts from the reading. The second introduces you to an integrated agriculture system called aquaponics.

| View | Upload your own

| View | Upload your own

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?

GREENHOUSE DESIGN PROJECT Part III. (50 pts)
Continue with your greenhouse design project. Remember to contact your instructor if you have questions. The next assignment is available in PDF format here.

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,

buddy

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

Boron Deficiency on Hydroponically Produced Melon.

INTRODUCTION
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

LEARNING OBJECTIVES

• 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

TERMS TO KNOW
nonfertilizer (non-mineral) nutrients
primary macronutrient
secondary macronutrient
pH
pre-plant fertilization
post-plant fertilization
rule of 75
backflow preventer
proportioner
liming materials
dolomitic limestone
sulfur, iron sulfate, aluminum sulfate
slow-release fertilizer
polymer encapsulated fertilizers
slowly soluble fertilizers
urea
sulfur-coated fertilizer
chelated micronutrients
PourThru method
Press Extraction method
Foliar analysis

READING ASSIGNMENT

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.

ACTIVE LEARNING EXERCISES

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?

******MAKE SURE YOU REVIEW THIS PART OF THE ASSIGNMENT EARLY IN THE WEEK, IT WILL TAKE TIME AND YOU MAY HAVE QUESTIONS FOR ME******

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)

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

Automatic Irrigation System for Hanging Baskets

INTRODUCTION
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.

LEARNING OBJECTIVES

• 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.

TERMS TO KNOW
absorption
alkalinity
reverse osmosis
Moisture Probes
hard water
diffusion
hose watering
softened water
flooding
low volume watering
acidifying water
transpiration
trickle irrigation
chlorine
guttation
drip tube
fluorine
surfactants
moisture stress
spray stakes
wetting agents
soluble salts
boom irrigation
tensiometer
ebb and flood irrigation
capillary mat

READING ASSIGNMENT

1. Read Chapter 8: Watering in your text. pages 257-301

Ebb and Flow system adapted to the entire floor of a greenhouse.

ACTIVE LEARNING EXERCISES

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.

EXAMS HAVE BEEN E-MAILED

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

DO NOT OPEN THE ATTACHED FILE UNTIL YOU ARE READY TO BEGIN THE EXAM.

GOOD LUCK!

EXAM REMINDER

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!