2015 Experiment Station Bulletin
Department of Agriculture Alcorn State University
Publication Number 2 August 27, 2015 High Tunnel Greenhouse: An Overview Patrick E. Igbokwe Professor of Horticulture and Director Alcorn Experiment Station Franklin O. Chukwuma Assistant Professor of Environmental Science and Coordinator, Off-Campus Centers Alcorn State University Extension Program
Dr. Alfred Rankins Jr. President, Alcorn State University Dr. Donzell Lee, Provost and Executive Vice President for Academic Affairs Dr. John Igwebuike, Vice Provost, Academic Affairs Dr. Ivory Lyles, Dean and Director of Land-Grant Programs School of Agriculture, Research, Extension and Applied Sciences Dr. Wesley Whittaker, Assistant Dean School of Agriculture, Research, Extension and Applied Sciences
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TABLE OF CONTENTS
Components of High Tunnel………………………………………………………………………………….…...3 Requirements for Purchasing High Tunnel…………………………………….…….…………..……3-4 Size Trellising Snow Load/Wind Mobility Site Selection
Types of High Tunnel Greenhouses…………………………………………………………………………...4 Quonset or Hoophouse Gothic Multi-Ray Caterpillars Low Tunnels
Production Practices in High Tunnel Greenhouse……………………………………………..………5 Row/Bed Preparation Crop Rotation Plant Spacing Row Covers Crop Support Watering Fertilization Ventilation Heat Diseases/Pests Sanitation Pollination Harvesting
Economics and Marketing……………………………………………………………………………..…………..7 Information Sources………………………………………………………………………………………….………8 Recent Related Research Publications………………………………………………………….….……....9 Acknowledgement………………………………………………………………………………………………..…10 Financial Assistance………………………………………………………………………………………………..11 Disclaimer………………………………………………………………………………………………………...…….12 Experiment Station Photo Gallery…………………………………………………………………..….13-14
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High Tunnel Greenhouse: An Overview Introduction: A high tunnel greenhouse is defined as a relatively inexpensive and effective way of protecting high-value crops from the effects of marginal low temperatures, wind and rain, some insects and foliar disease pests, and wildlife damages. It could be considered as an unheated structure covered with a layer of clear polyethylene plastic to extend the crop growing season by a month or more. It is designed so that gardeners can have a year-round production of their favorite crops in a safe and warm environment. Some people refer to it as a tunnel made of polyethylene, usually semi-circular, square or elongated in shape. The incoming solar radiation from the sun warms plants, soil, and other things inside the tunnel faster than heat can escape the structure. The air warmed by the heat from hot interior surfaces is retained in the structure by the roof and wall. Although high tunnels do not offer the precision of conventional greenhouses for environmental control, they do sufficiently modify the environment to enhance crop growth, yield and quality. They protect plants from wind, rain, soil, insects, diseases and predators. Generally, these growing systems enhance earliness and higher yields, improve quality, and reduce the use of pesticides.
Requirements for High Tunnel Purchase: Things to consider when purchasing a high tunnel greenhouse include: (1) Size (2) Trellising (3) Snow load/ Wind (4) Mobility and (5) Site Selection. Size: Narrower tunnels are easier to ventilate regardless of the length. Tunnels should be wider than 30 feet to allow for optimal air flow. Tunnel width is influenced by price, available package dimensions and site. Tunnel up to 30-feet wide will hold accumulated heat better in winter than shorter and narrower structures. Trellising: Both gothic and hoophouses allow for vertical trellising common for indeterminate tomatoes and cucumbers. Multi-bay units are better suited to crops that can be horizontally trellised such as determinate tomatoes, peppers or eggplants, and, also, for crops that do not require trellis such as strawberries. Snow Load/Wind: Gothic types are better able to withstand snow loads and wind. Mobility: Tunnels that sit on top of the soil can be moved with moderate effort to fresh soil annually. This has benefits for soil health and disease and pest reductions. It is more vulnerable to wind damage and must be securely anchored. Tunnels that have in-ground posts can’t be moved rapidly. Site Selection: Since most high tunnel greenhouses are permanent structures for growing crops for many years, the site for their locations must be carefully selected. The most important things to consider in site selection may include: drainage, shade, wind, airflow and soil. a. Drainage: Proper drainage is essential. Having a slope or shallow trench along the edges will keep water from entering through the sides. Aligning the long-axis on a very slight slope will help with drainage and air movement. b. Shade: Avoid shade from trees and buildings. Shade located on the east side of the tunnel will prolong morning leaf wetness; and increase the chances of foliar 3
diseases. Avoid shade completely for fall crops as cool season crops need much sunlight as possible during the short days with low sun. c. Wind: Is an enemy to tunnels. Minimize exposure to reduce wind damages. d. Airflow: Although high winds are not acceptable, orienting the high tunnel perpendicular to the predominant breezes to maximize cross ventilation through the sidewalls cannot be overemphasized. e. Soil: Soils high in fertility should be considered. Naturally fertile soil which will help to feed the rapid growth that occurs inside the tunnel should be considered. Avoid soils that are easily compacted and limit use of heavy machine on such soils. For summer crops such as tomatoes or peppers north-south orientation allows maximum sunlight to penetrate the rows. It also maximizes ventilation through sidewalks where westerly winds predominate, helping to reduce overheating and disease problems. For fall and early spring crops (cool season greens) east-west orientation provides maximum southern exposure and better sun penetration into the crop canopy.
Types of High Tunnel Greenhouses: The most common high tunnel greenhouses include: (1) Quonset or hoophouse tunnels (2) Gothic tunnels (3) Multi-bay tunnels (4) Caterpillars (5) Low Tunnels (1) Quonset Tunnels: Composed of rounded steal arches that create a single bay, usually 12 to 40 feet wide, 12 or 11 gauge steel arches spaced 4 feet apart or close enough to bear snow loads when plastic is left year-round. Has a straight side wall that adds to height and allows for growing tall plants on rows along the walls. Ventilation is controlled by raising and lowering the sidewalls. The length is variable. (2) Gothic Tunnels: These have peaked roofs which help the structure to shed snow. They are taller than Quonset or hoophouse tunnels. Inside temperature is more stable during the warmer months. (3) Multi-bay Tunnels: These are used to cover large acreages than other types. They are tall enough to cover fruit trees, and are large enough to easily accommodate tractor traffic. They have several spans of arches connected by common gutters at the roof seems. They are not intended to withstand snow-loads or high winds. (4) Caterpillar Tunnels: They are narrow single bay structures often barely tall enough to stand in. they are improvised by farmers using plastic sheeting spun polyester row-covers and other materials. They are temporary structures that are all unable to withstand significant snow or wind unless tightly secured. (5) Low Tunnels: They are smaller than caterpillars, usually about 1.5 to 2 feet tall. They can be used within hoophouses for added protection to winter harvested crops such as greens or to help overwinter tender crops as some herbs.
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Production Practices in High Tunnel Greenhouse The essential production practices needed for successful high tunnel greenhouse operations will include row/bed preparation, crop rotation, plant spacing, row cover application, crop support, watering, fertilization, ventilation, disease and pest managements, sanitation and pollination. Row/Bed Preparation: Rows are formed as for regular field plots. The width and height will depend on the setting of equipment. Beds should be about 6-10� high and 24-30� wide. Building of beds is with compact bed shapers or power tillers. Establish drip irrigation system; fertilize, and mulch after the beds are formed. Crop Rotation: Used as a method of (1) keeping soil borne pathogens in check (2) managing nutrients for a sound soil health program. As in field plots, similar vegetables must not be grown on same plot year after year. Crops in rotation must be from different family and/or have different growth habits and nutrient requirements. Plant Spacing: Similar to transplanting into field plots. True for both within and between rows. Using recommended spacing will prevent competition from different growth factors. Significant low or high plant density will lead to poor and unhealthy plants, resulting in low crop yield and quality. Row Cover: Used in cold season to provide additional 2 to 8 degree Fahrenheit increase in temperature. It allows for proper light, water supply and air circulation. It therefore modifies the environment to enhance crop growth, yield and quality. It is a piece of light weight, semitransparent fabric constructed from spun-bonded polypropylene or polyester. Crop Support: Similar for field-grown trellised crops. Trellis may be wires, strings or poles as desired. Use of both vertical and horizontal trellising will vary with growth habit of crop planted. It allows climbing plants the opportunity to have greater exposure to sun and air, while keeping them off the ground to reduce rot and diseases. Watering: Drip irrigation is preferred for uniform water application. It uses less water than sprinkler irrigation, and is better during fertigation. It will reach the high concentrations of salt from around the plant roots thereby reducing the salt problem. Water is a vital component to the survival of plants as it aids in their photosynthesis, growth respiration and rigidity. Fertilization: Soil testing is as essential as for field plots. Total application may be less for high tunnel. The purpose will determine the source, form, method, time of applications, harvest desired, as well as the crop family. Fertilizers aid in replenishing and maintaining long term soil fertility by providing optimal conditions for soil biological activities. Ventilation: Provided with manually operated side vents. Raising and lowering the side walls assist with airflow. Vents may be oriented perpendicular (at right angles) to the prevailing winds on one’s farm. Cross ventilation will remove humid air and moderate air temperature during the day. High humidity greater than 85% will prevent disease problems. Taller structures allow for better airflow.
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Tomato Cultivar Evaluations in the Alcorn State Experiment Station High Tunnel Greenhouse
Heat: May not have heat source in the high tunnel, however, portable heater may be used during sever cold weather conditions. Row covers may be used for back-up frost protection. Diseases and Pests: Will be controlled with reduced pesticide and fungicide applications, and the use of resistant crop varieties. You must avoid the presence of susceptible crop variety, disease organism, and suitable environment for their growth and development. Disease resistant cultivars are the first line of defense against plant pathogens. Using biofumigant covers, crops such as mustards, marigold, flax and rapeseed in rotation or as intercrop will result in the release of chemicals that grow plant pathogens, nematodes and some weeds when they die and decompose. Sanitation: Remove and destroy any diseased plant parts as soon as they are found. Perform daily tasks in the tunnels before field work. Clean off properly before bringing tools and clothes to the tunnel. Deeply incorporate, remove, destroy or compost at a distance, plant materials including roots. No volunteer plant should be allowed to establish in the structure at any time to prevent problems from aphids of thrips. Pollination: Involves transfer of pollen to the stigma of a flower. This process is needed for crops to set fruit. Pollination may occur in two forms: hand-pollination or through the use of native or purchased bees. Mature pollen must be deposited on the stigma to initiate fertilization and fruit formation. Using a leaf blower every day or every two days can assist with pollination also. Harvesting: Crops are harvested at least a month before those grown in the field plots. Year-round harvest is possible when the spring, summer and fall seasons are utilized.
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Herb (Variable) Productions in the Alcorn Experiment Station High Tunnel Greenhouse
Economics and Marketing: It has been reported that a high tunnel greenhouse will allow for season extension by a month or more, provide for early and late season produce which command premium prices, result in reduced weather defects and disease pressure on plants, protect plants from wind and wildlife destruction, reduce weed seed germination due to moisture applications to desired areas, and will lead to low initial cost of investment and high returns from harvested crops.
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Information Sources:
http://extension.psu.edu/plants/plasticulture/technologies/high-tunnels http://www.hort.cornell.edu/hightunnel/index.html http://www.rimolgreenhouses.com/greenhouse-series/high-tunnel/?gclid=CNzwzaCA98U http://www.ehow.com/way_5585995_diy-greenhouse-tunnel.html?ref=Track2&utm-sourc Byczyngki, L. 2003. The Hoophouse Handbook. Growing for the Market. Coleman, E. 2009. The Winter Harvest Handbook. Chelsea Green Publishing Co., White River Junction, VT. http://sustainable-farming.rutgers.edu/high-tunnels-in-new-jersey/ http://en.wikipedia.org/wiki/polytunnel
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Recent Related Research Publications
Igbokwe, P.E., D. Alipoe, and M. Rizvi. 1996. Sustainable agriculture for vegetable production in Mississippi. Journal of the MAS 41(3):136-142. Igbokwe, P.E., 1996. Mulching for nutsedge control in field-grown peppers. Journal for Vegetable Crop Production. 2(1):47-52 Igbokwe, P.E., and S. Hollins. 2000. Response of Vegetable Amaranth to Plant Spacing. Journal of Vegetable Crop Production. 6(2):75-85. Igbokwe, P.E., L.C. Huam, Magid Dagher, Lashunda Anderson and Charles Burandt. 2002. Echinacea Cultivar Evaluation in Southwest Mississippi. Journal of Mississippi Academy of Sciences. 47(4):189-193 Igbokwe, P.E., L.C. Huam, F.O. Chukwuma, and J. Huam. 2005. Sweet potato yield and quality as influenced by cropping systems. Journal of Vegetable Science. 11(4):35-46. Igbokwe, P.E., L.C. Huam and W. Whittaker. 2006. A Handy Guide to Hot Pepper Cultivation and Utilization. Alcorn State Unviersity Bulletin 2006-1. Igbokwe, P.E., F.O. Chukwuma, and A.L. Burks. 2007. Basics in Organic Vegetable Production. Alcorn Experiment Station Bulletin 2007-1. Igbokwe, P.E., F.O. Chukwuma, and A.L. Burks. 2007. Composing Made Easy. Alcorn Experiment Station Bulletin 2007-2. Igbokwe, P.E., M. Dagher, J. Buzardt, F. O. Chukwuma, A.L. Burks. 2007. Shiitake Mushroom Production. Alcorn Experiment Station Bulletin 2007-4. Igbokwe, P.E., F.O. Chukwuma, A.L. Burks. 2007. Basics in Organic Vegetable Production. Alcorn State University Bulletin 2007-1. Igbokwe, P.E., F.O. Chukwuma, A.L. Burks, V. Igbokwe, and Z. Cuadra. 2011. Onion Production at the Alcorn State Unviersity Experiment Station. Advances in Science and Technology (5)2:109-112. Igbokwe, P.E., Thomas Quincy and Arkon Burks. 2013. Enhancing Tomato (Lycopersicon esculentum) Production and Utilization. Advances in Science and Technology 8(1):47-52. Igbokwe, P.E., and A. Gibson. 2014. Echinacea Seed Germination, Plant Growth Potential and Quality. Advances in Science and Technology 8(2):77-82. Igbokwe, P.E., Arkon Burks, Donzell King, Zulma Cuadra and Titus Sombuor. 2014. Indoor Production of Shiitake Mushroom in Southwest Mississippi. Alcorn Research Report 1(2):1-7.
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Acknowledgement
Alcorn State University Experiment Station scientists and staff extend their appreciations to the state of Mississippi legislators for providing the funds for the successful operation of the Station. Similar appreciation is extended to Alcorn President Dr. Alfred Rankins Jr. and Alcorn administration for supporting scientific research at the Station. Contributions from other Alcorn scientists, faculty, Experiment Station staff (Carl Campbell, and Richardson Boeateng) and students are highly appreciated.
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Financial Assistance
Interested producers seeking assistance with the installation of a high tunnel should check with their local USDA Natural Resources Conservation Service (NRCS) office for guidelines for Environmental Quality Incentives Program (EQIP) funding for high tunnels, which can cover approximately 75% of the cost of installation.
Figure 3: Side view of high tunnel greenhouse at the Alcorn State University Experiment Station
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Disclaimer Mention of a trademark or proprietary product does not constitute a research grantee or warranty of the product by Alcorn State University School of Agriculture, Extension and Applied Sciences (AREAS) and does not imply its approval to the exclusion of other products that also may be suitable. Alcorn State University does not discriminate on the basis of race, color, religion, national origin, sex, age, disability, or veteran status. Alcorn Experiment Station Bulletin Publication 2015 #2
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15 Alcorn State University does not discriminate on the basis of race, color, religion, national origin, sex, age, disability or veteran status.