Learning Objectives
The lesson plan objectives are to provide a comprehensive training in high tunnel operations by educating on all aspects of the high tunnel, from construction to economics to soil fertility and crop management. This lesson plan includes seven different units, each focusing on specific aspects of high tunnels.
Participants will learn:
- How to construct a high tunnel (15 × 40 ft), proper site selection for the high tunnel, construction details, and design features.
- How to set up a drip-irrigation system in the high tunnel and maintain it and be able to demonstrate this.
- How to interpret a soil analysis, specifically aspects that may be overlooked in the field but that are especially important in high tunnels, such as electro conductivity or soluble salts.
- How to prepare the soil accordingly for crop production and manage the soil sustainably and specifically for a high tunnel.
- The importance of timing with respect to crop planting. Students also will learn about various crop rotations and possible intercropping combinations within a high tunnel system and be able to explain this and provide hypothetical recommendations. The training will provide examples with specific crops, both commonly grown (tomatoes and cucumbers) and less commonly grown (herbs, flowers, medicinal plants).
- The basics of integrated pest management (IPM) strategies specific to high tunnels and how one would hypothetically provide recommendations to growers.
- The cost associated with all aspects of a high tunnel system, from construction to production to maintenance.
- What it takes for a grower to prepare for market, the tools to better understand their local market, and the costs associated with getting to market.
The goal of this high tunnel unit is to provide accurate and current information to participants and equip them with useful skills related to high tunnels. This will help prepare them to be growers or be able to assist growers as a county Extension agent or crop consultant. It also will help foster more sustainable and productive high tunnel operations. The long-term objective is to better serve current and future high tunnel growers.
Introduction
High tunnels, also known as hoophouses, are passively heated and cooled temporary structures used to extend the growing season for high-value crops. They provide protection from the weather and serve as a moderately controlled environment. Over 1,500 high tunnels have been installed in the state of Kentucky since the inception of the High Tunnel System Initiative within the Natural Resource Conservation Service Environmental Quality Incentives Program (NRCS EQIP) in 2012 (Deena Wheby, NRCS, personal communication). Many growers have been able to take advantage of the low-cost (or free) addition to their farm. High tunnels have the potential to provide growers with the ability to extend the growing season and moderate the environment with respect to precipitation and temperature. This can translate to increased income from increased marketable yields and improved produce quality (Kadir et al., 2006; O'Connell et al., 2012; Rader and Karlsson, 2006; Rogers and Wszelaki, 2012). Many growers are unfamiliar with how to most effectively use their high tunnels and get the most out of the potential season extension. The funding available through NRCS has opened high tunnel ownership to a wider social and economic stratum; it has included people that may not normally be able to afford a high tunnel or who are not experienced growers. High tunnel production is nuanced, and even experienced growers struggle with the unique production challenges.
This lesson plan was originally designed and executed as Extension programming to train county Extension agents in Kentucky to help address high tunnel issues. There was both a lack of appropriate information and a lack of communication between Extension agents and the grower community. Based on discussions with agents, much of this is due to their discomfort with the topic (not knowing the answer can be uncomfortable), as opposed to their disinterest in helping growers. Many agents rely on faculty specialists to go to their counties and provide information to growers. This is not a sustainable form of information exchange, however, as there are far fewer specialists than there are county agents. Additionally, the county agents are living and working in their communities and can better assess the needs and wants of their growers.
This lesson plan was designed to be taught over the course of two years with three units per year to allow for the time constraints of county agents. Each unit has time for lecture followed by hands-on activities and demonstrations. However, this lesson plan could be taught at the college level over the course of a semester and could be combined with other lesson plans in a vegetable production course. This lesson plan lends itself well to being taught in collaboration with others who may have expertise in a specific topic related to high tunnel operations.
Activities
Unit 1—High Tunnel Basics
Lecture
Provide an overview of what high tunnels are since many students may not know. Provide a definition of a high tunnel since it is often confused with a greenhouse. Describe what makes a high tunnel different from a greenhouse. Be sure to cover the following aspects:
- How high tunnels can be beneficial to agriculture and potential drawbacks of high tunnel production. Crops that can be grown in a high tunnel because of increased quality and marketable yield. Discuss why certain crops are better for high tunnel production than others.
- A major aspect of high tunnels is season extension. Describe what that means and provide examples.
- Site selection for a high tunnel. A high tunnel cannot be placed just anywhere. Discuss why not. Aspects of site selection: soil type, drainage, hills, cropping history, water source. High tunnels do not need electricity, but it would be beneficial. The addition of electricity may influence the location.
- Tunnel orientation. Discuss both wind and sun. Trees may influence orientation, as well as the location.
- Site preparation. Drainage, grading, and tillage should all be considered. Bottom line—the ground inside the high tunnel needs to be level. Discuss why this matters for future production and management. Provide examples.
- Design considerations: dimensions, bow spacing, structure material (wood versus metal), plastic layers (single versus double layers), end-wall options and considerations, side-wall options and height recommendations, ventilation options, and other potential additions, such as shade cloth and fans. Optional: discuss moveable high tunnels—benefits and potential drawbacks.
- Soil management: discuss soil sampling and why it is important and how often sampling should occur. Soil salinity is a concern in high tunnels. Discuss why this occurs and how can it be prevented or remediated.
- Crop management: discuss rotation, crop spacing, and managing the shoulder seasons. Provide general ideas for crop rotations and what ideal rotation would look like. Discuss planting dates for different crops, the benefits of transplanting versus direct seeding, and what may influence which crops should go in a high tunnel and which crops can remain in open-field production.
- Temperature management is influenced by the crops growing in the high tunnel. Provide examples. Discuss what influences the temperature inside a high tunnel: wind, sun, shade cloth, row cover. Discuss how the temperature in a high tunnel differs from the open field.
- Considerations for high tunnel production. Provide examples of potential issues and factors to be aware of in high tunnel production.
- Circle back to overall conclusions/takeaway messages.
- Provide a list of general high tunnel resources relevant to your region/area.
Lab
The lab day will comprise a field trip to nearby commercial grower high tunnels. If possible, visit at least two farms so students can see differences in high tunnel structure details, placement, crop production, and overall management. If the grower(s) are willing, a question and answer session would be best so students can hear directly from the growers about their high tunnels.
Materials/Resources
Unit 2—High Tunnel Construction
High tunnel construction is almost entirely lab work and is optional. This unit may be challenging to execute due to constraints on funding or land where construction can take place. Construction of one 15 × 45-ft high tunnel will take six people approximately three 8-h days with breaks for lunch. This assumes there is at least one person with previous high tunnel construction experience. There should be at least two instructors leading the construction to make sure people are making the most of their time and paying attention. If teaching undergraduate students, this unit is likely to take two to three lab periods, depending on the length of each lab class and the class size. There is minimal lecture, but providing a handout to students that includes the names of the structural components of a high tunnel—bow, purlin, etc.—would be helpful. These terms are important. Each day or lab period should begin with safety reminders before construction takes place.
Materials/Resources
See construction document for list of supplies and description of how to set up a high tunnel.
Unit 3—Soil Fertility and Management
Lecture
Many participants may already know how to properly sample soil for soil-testing purposes. What they may be less familiar with is how to interpret results to make management and fertilizer decisions or how to provide specific recommendations to high tunnel growers based on soil test results. The test results from most soil-testing laboratories include general recommendations for the future crop to be grown, such as "Apply 30–60 lb of N/acre." However, there are many sources of nitrogen, and growers often choose the fertilizer with which they are most familiar rather than the fertilizer that is most appropriate for their soil and crops. Participants will learn about and be able to discuss the advantages and disadvantages of different fertilizers and the appropriate timing of applications. They will learn about soil salinity and the importance of testing for soluble salts. Participants also will learn about various prevention and remediation methods for soil salinity. Be sure to cover the following information:
- Different testing labs will likely provide different results. Discuss why this is important. Send the same soil to two different labs and discuss those results. There may be certain aspects that are similar or very different. Discuss how changing testing labs could affect soil fertility and management.
- Learning to read and interpret soil test results.
- Understanding fertilizer labels. Explain what NPK means and what it means for plant-available nutrients. How do we use this information to make application decisions?
- Calculating fertilizer applications based on soil test results and recommendations. Provide at least three examples. Provide an example overapplying certain nutrients as well, using a fertilizer that contains nutrients that are not really needed based on the soil test results.
- Discuss building organic matter, the best ways to do this, and what should be avoided.
Discuss the importance of soil pH and what lime and sulfur applications do and the timing needed for these applications.
Lab
This can be approached a few different ways depending on the experience level of the students but could include the following:
- Visit/tour a soil-testing lab where they can explain the process, from receiving a sample to getting a result to the grower, and show the equipment they use.
- Proper soil-sampling technique—do's and don'ts.
- Discuss and demonstrate the different equipment that can be used to apply fertilizers in a small space, such as a high tunnel.
- Cover crop demonstration plot that showcases different seasonally appropriate cover crops. The potential advantages and challenges of each species can be discussed much more easily when viewing them and their growth habits.
Materials/Resources
Unit 4—Irrigation and Fertigation
The irrigation workshop exposes participants to different irrigation systems that growers may use. Participants will learn how to set up a drip irrigation system that also allows for the possibility of fertilizing through the drip-irrigation lines (fertigation). A list of supplies will be included in the training session so that participants can use it to purchase what they need and can pass that information on to growers. This is best discussed after the soil fertility unit because calculating fertilizer applications will be important to this aspect of the lesson.
Lecture
High tunnels have been referred to as "irrigated deserts." This is basically true as plants grown in open fields are exposed to precipitation in addition to irrigated water, while plants in high tunnels are not. The ability to control the water that plants receive is one of the benefits of high tunnels as it can help prevent disease and maintain marketable fruit. Drip irrigation, rather than overhead irrigation, is recommended for vegetable crops and most specialty crops. Not only does drip irrigation utilize water more efficiently, putting it near crop roots where it can be readily taken up, it also is helpful in preventing disease by reducing moisture on leaves.
After discussing why drip irrigation is recommended, discuss the options for water sources—municipal, river, pond, well, rain, etc. For each water source, a different approach will need to be taken to get water from the source to the high tunnel. This involves calculations. Provide at least two examples to students, one with high pressure (municipal water source) and one with low pressure (rain water catchment). Next, discuss fertigation and why it is useful. Incorporate fertilizer calculations learned in the previous unit to teach students how to calculate fertigation applications.
Lab
Participants will be shown different options for creating an irrigation manifold, and then, they will practice building a manifold. Discuss the different components of the manifold and why it is needed. There is an option to add a fertigation component to the manifold. Demonstrate fertigation and what is needed to do this successfully.
Materials/Resources
Unit 5—Crop Management
This unit covers soil preparation, planting, proper crop rotation, and management of crops across the season. Ideally, you would have one high tunnel that has already been prepped and planted and one that still needs to be prepped and planted so that students can see the final product but also will have the ability to practice and prepare a tunnel for the growing season.
Lecture
Discuss the general factors involved with managing crops in a high tunnel, which include air temperature, humidity, soil moisture, soil fertility, pests, diseases, and weeds. How does each component influence the crops being grown? How could this be different in a diversified high tunnel compared to a monocropped high tunnel? With each season, the management changes, and more focus may be on certain factors.
Lab
Depending on the length of this class, this lab could be more than one day and be something that students are responsible for over the course of several weeks. Students will have the opportunity to prepare a high tunnel for planting. This includes preparing the soil, which may include tilling, applying fertilizer, testing irrigation, and laying the weed mat. They will then transplant season-appropriate crops.
Materials/Resources
Unit 6—Integrated Pest Management (IPM)
Students will learn common production issues specific to high tunnel production and what prevention and management steps may be taken. The unit will cover the basics of IPM and what it encompasses—entomology, plant pathology, weeds science, and horticulture.
Lecture
Define IPM, its different components, and what it means when practiced/applied on a farm. Discuss with students the common issues observed in high tunnels in your area. Describe these issues, what causes them, and how they can be prevented and/or managed with IPM. How do horticultural practices relate to IPM?
Lab
This lab is flexible and can vary depending on the experience level of the students and what kind of practice they are interested in gaining. The lab could include the following:
- The basics of scouting for pests and diseases. What to do and how to do it. What sort of monitoring tools can we use to alert us to issues?
- Disease, pest, and weed identification in the high tunnel. This may require either keeping one high tunnel less maintained or making a visit to a grower's farm where they have known issues and have agreed to allow this sort of active field trip.
- The role of sanitation in IPM. What does this mean? What sorts of things should be sanitized and how often?
- Demonstration (with water) of pesticide applications using a variety of sprayers. Explanation and demonstration of different nozzle types and what products are best for different nozzles.
- Calibration of sprayers for pesticide applications.
Materials/Resources
Unit 7—Economics, Marketing, and Cost Analysis
Lecture
If this is a standalone lesson plan, not combined into a larger class, it may be best to cover general economic terms so that all students begin the lecture with the same information. Examples include terms such as "fixed costs" and "net cash flow." You can then move into more high tunnel-specific information. Discuss the primary marketing advantages for producing out of a high tunnel, as well as the typical marketing channels for high tunnel producers in your region/state. Discuss the fact that a high tunnel is added infrastructure to a farm, and therefore, the grower/owner needs to figure out how to cover the cost of maintaining it. How do or should they go about doing a market assessment? What are some of the important product qualities local food consumers look for, and how could that be integrated into a grower's marketing plan?
Lab
This lab can be approached in a variety of ways depending on how this lesson plan is being utilized:
- Option 1: Ask participants to pretend they are high tunnel growers and do their own market assessments. Suggested questions: What will you sell? Where will you sell? How will you be profitable?
- Option 2: Pair participants with real high tunnel growers in your area and have them interview the growers on their marketing channels and strategies. (Be sure to compensate the growers for their time.)
Materials/Resources
Optional Additional Units
For a course that is a semester long, one would need to aim for approximately 14 weeks of curriculum. Unit 2 could easily be 2 weeks, as construction could take more than 1 week depending on the number of students and how in-depth the instructor wanted to be with respect to construction details. Unit 3 could also extend over 2 weeks, with more traditional fertility and calculations discussed in the first week and cover cropping, manure, and compost covered in the second week. Unit 5 could be split into two separate units, with one focusing on cool season crop management and another focusing on warm season crop management. For a course that is a semester long, working with both cool season and warm season crops would be feasible. There are different management strategies depending on the season, and this would provide participants with a more realistic experience of high tunnel season extension. Unit 6 could extend over 3 weeks, with each week focusing on a different aspect of IPM. Week 1 could focus on high tunnel diseases, week 2 on arthropod pests, and week 3 on weeds. Other potential units could include high tunnel structural maintenance and upgrades, equipment and tools, and pesticide applications, calibrations, and safety.
Cumulative Learning Assessment
Participants can be surveyed at the beginning of the workshop series and also at the beginning of each unit to ascertain their level of skill, knowledge, and comfort related to high tunnel production. Participants can also then be surveyed at the conclusion of each unit to evaluate the effectiveness of the training and to consider alterations to future training sessions. If all participants complete all units, a comprehensive survey can be conducted at the end of the training series/semester course to determine their level of confidence and knowledge after participating in the full training series.
If everyone completes the trainings series, another component to add would be to ask student participants to put on a field day or training session for growers or potential high tunnel growers under the supervision of the instructor(s). The instructor(s) would provide support and evaluate the quality of the presentations and training sessions. Participants would receive constructive feedback after their presentations.
Training sessions can be filmed and edited to provide open access online tutorials. Hard copies of resources pertinent to each training session can be provided to participants, with the option to have a digital version emailed.
Instructor Notes
In the case of the agent training series, not all Extension agents participated in all units. However, if they had, I would have like to have asked them throughout the training series (via surveys) whether they had incorporated any of what they have learned into their existing county-level programming or if they created new programming because of what they had learned. It would have been nice to be able to follow up with agent participants to quantify the number of people they had been able to educate or provide recommendations to because of this training series. The network of growers with whom agents interact may have expanded because the agents have become more knowledgeable and comfortable with sustainable high tunnel production systems.
References
Edmeades, D. C. 2003. The long-term effects of manures and fertilisers on soil productivity and quality: A review. Nutr. Cycl. Agroecosyst. 66:165-180.
Kadir, S., Carey, E., and Ennahli, S. 2006. Influence of high tunnel and field conditions on strawberry growth and development. HortScience 41:329-335.
O'Connell, S., Rivard, C., Peet, M. M., Harlow, C., and Louws, F. 2012. High tunnel and field production of organic heirloom tomatoes: Yield, fruit quality, disease, and microclimate. HortScience 47:1283-1290.
Rader, H. B., and Karlsson, M. G. 2006. Northern field production of leaf and romaine lettuce using a high tunnel. HortTechnology 16:649-654.
Rogers, M. A., and Wszelaki, A. L. 2012. Influence of high tunnel production and planting date on yield, growth, and early blight development on organically grown heirloom and hybrid tomato. HortTechnology 22:452-462.
Yao, L. X., Li, G. L., Tu, S. H., Gavin, S., and He, Z. H. 2007. Salinity of animal manure and potential risk of secondary soil salinization through successive manure application. Sci. Total Environ. 383:106-114.
