Resources • High tunnels: using low-cost technology to increase yields, improve quality, and extend the season. T. Blomgren, T. Frisch and S. Moore. [Online] (n.d.) University of Vermont Center for Sustainable Agriculture, Burlington, VT. Available at:
http://www.uvm.edu/sustainableagriculture/hightunnels.html (verified 4 March 2010). This guide includes organic-specific information, including organic farm case studies. There is also an accompanying video available for purchase.
The Benefits of High Tunnel Production
• High tunnel production manual, 2nd Edition. 2003. W. Lamont. Pennsylvania State University. Available for purchase at: http://plasticulture.cas.psu.edu/manual.htm (verified 4 March 2010). This is a conventional production guide that includes one chapter on transitioning a tunnel to organic production.
For additional information contact: Dr. Franklin Chukwuma Coordinator for Off-Campus Centers Toll Free: 1.877.427.9536 or 601.877.2312 Email: franklinc@alcorn.edu
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High Tunnel
Benefits of High Tunnel Production
High tunnels are low-cost freestanding or gutter-connected covered structures, without heating or electrical power, that uses passive ventilation for air exchange and cooling, and an irrigation system for crop production.
• High tunnel production is a hybrid of open field and greenhouse production.
“Hoophouse” is another name that is used interchangeably with “high tunnel” and means the same thing. High tunnels could simple be made from all pipes or another type of framework covered by a single layer of greenhousegrade 4- to 6-mil plastic, or they can be as complicated as greenhouses.
Types of High Tunnel High tunnels are generally quonset- or gothic-shaped. They are most often constructed of metal bows which are attached to metal posts, driven into the ground. They are typically covered with one or two layers of 6-mil greenhousegrade polyethylene, and are ventilated by rolling up or removing the sides or ends. There are various designs each offering advantages and disadvantages. Due to their permanent nature, care should be given to sitting the high tunnel properly. Quonset-shaped: The quonset-style hoop house has historically been the most popular high tunnel shape due to its simplicity. However, the circular shape limits the height at the sides of the high tunnel, limiting its use for crop production. In addition, the quonset shape cannot easily support a snow load, so the structure must be strengthened or the plastic must be removed before winter in regions that receive snowfall. However, the quonset shape increases the amount of light infiltration, which results in higher temperatures and improved crop growth. The Gothic Style: is rising in popularity due to the problems associated with the quonset style. This peaked design allows for greater height along the sides, making the sides of the high tunnel more useful for crop production and resulting in a 15% greater growing space than the quonset.
Uses of High Tunnel • Vegetables are the main crops growing in high tunnels around the world. The primary vegetable crops for high tunnel production, in order of importance, are tomato, sweet pepper, cucumber, muskmelon, lettuce, summer squash, and eggplant. The other major horticultural crops produced in high tunnels include small fruits, tree fruits and cut flowers. • High tunnels provide a protected environment compared to open field production. • High tunnels are used extensively to extend the growing season of the crop.
• It does not require as much capital investment as greenhouse production while providing a certain level of protection that field production could not offer. • In addition to the season extension aspect of high tunnel production, another major advantage of high tunnels is the exclusion of rain water; thus, less moisture on the foliage and reducing the amount of disease pressure. In tropical regions, high tunnels work more like a rain shelter to crop production during the rainy or monsoon seasons. • High tunnels, also, are used as wind breaks or storm protection to reduce wind damage on crops. • It has been reported on various crops that high tunnels yield better than field production when it comes to quality and quantity, which translates into better profit. • In most high tunnels, crops are grown on plastic mulch and drip irrigation is employed to provide water to where it is needed. Weed seed germination is reduced tremendously due to no natural rain water and less soil moisture where crops are not grown. Less bird, insect or other similar damages Crops are protected by the plastic from birds or deer damage. Insect screen could be installed to prevent entry of insects and; thus, reduce damage on crops.
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.