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.
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!
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
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).
Compare and contrast the plant nutrition program of Eurofresh, Kraft Farm, and Crossroad Farm in a few paragraphs. (20 pts).
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)
What is the purpose of a back flow preventer.
Which essential elements come from the air and water?
Explain what essential nutrients (elements) are impacted by the Cation Exchange Capacity of a soilless media.
What essential nutrients are usually available in anionic forms that are easily washed out of the root substrate along with excess water?
Explain the differences in nutrient availability caused by pH in soil and soilless media
A purple color on the underside of the seedling leaves of marigolds and tomatoes is a sign of what two production problems.
Describe the difference between a slow release fertilizer and a slowly soluble fertilizer.
Name the essential nutrient at the center of every chlorophyll molecule.
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.
A petunia grower notices some purple discoloration on the underside of older leaves. Some leaves are brown and papery. What nutrient is likely deficient?
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?
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.
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
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
Watch Audio PowerPoint Lecture on Greenhouse Irrigation (approx. 40 minutes). Depending on your Internet Connection Speed this may take some time to download.
Search the Digital Greenhouse Repository using the keyword "irrigation"; study the pictures and read the abstracts when available.
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).
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.
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)
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).
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)
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)
Compare and contrast 3 different containerized plant watering systems (you can choose). Make sure you indicate the advantages and disadvantages of each. (10 pts)
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.
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.
This course covers the principles and procedures involved in the operation and maintenance of greenhouse facilities. Emphasis is placed on the operation of greenhouse systems, including the environmental control, record keeping, scheduling, and production practices. Upon completion, students should be able to demonstrate the ability to operate greenhouse systems and facilities to produce greenhouse crops.
All these images were obtained from Flickr under a Creative Commons License. By going to Flickr.com and searching the member name found next to the image source you can find the image and more by the same photographer.
