What can you tell me about hoop house (or high tunnel) construction and use?

R.S.MississippiAnswer: I am pleased to provide you with information regarding hoop house (or high tunnel) construction and use.Please refer to the ATTRA publication that details high-tunnel and greenhouse information, titled “Season Extension Techniques for Market Gardeners.” This publication has detailed information on using high tunnels for season extension on your farm as well as rudimentary plans on constructing them in the appendices. In your region, a hoop house would be most effective as a season extension tool in the winter, early spring, and late fall. Over wintering cool season crops, such as lettuce, radishes, and other greens, can be planted in there or you can extend your warm-season crops further into the late fall or earlier in the late springearly summer.A hoop house in your region can also be used to start vegetable transplants in the early spring. Listed below is a publication from Mississippi State University Extension Service on starting transplants in greenhouses. This publication breaks down the best time to start certain vegetables for the difference regions within your state. Generally hoop houses, or high tunnels, are simple unheated “greenhouse-like” structures that provide less control of environmental conditions than full greenhouses at substantially less cost. They are usually covered with a single layer of plastic and are ventilated only through roll-up sides. A typical high tunnel does not have a heating system, and I do not think it would be necessary in your climate. Drip irrigation is often used in high tunnels. The production system may be in-ground culture, or pots can be placed on the ground or on benches. The hoops for the high tunnel are often placed approximately 4 feet apart. Many plans call for using 2″ PVC for the hoops, which is a more economical alternative, but they tend to be less rigid and more susceptible in areas of high winds. A narrow width of the building lends itself well to roll-up-side ventilation (approximately 14 feet or so). Tunnels and greenhouses with vertical sides which rise up before curving provide better side to side ventilation and allow for better use of growing spaces along the edges inside. In order to have vertical sides, however, you must use fabricated pipe, or bend the pipe yourself. High tunnels are commonly sold in units of 48 or 98 feet long, but they can be ordered in any length. The cost of a 14-by 96 foot unit of single poly, roll-up sides and including end-walls and doors, and drip tape is about $2000-$3000, depending on the construction materials (1). A great on-line resource for constructing and utilizing high-tunnels is http://www.hightunnels.org.This excellent on-line resource has three different plans on how to build simple hoop houses as well as cultural information on growing certain vegetables and fruits in them. It seems to be the best, comprehensive, and farmer-friendly resource about high tunnels on the internet. References:(1) Grubinger, Vernon. 1999. Sustainable Vegetable Production from Start-up to Market. Natural Resource, Agriculture and Engineering Service. Ithaca, NY. Resources:Bachman, Janet. 2005. Season Extension Techniques for Market Gardeners. NCAT ATTRA Publication # IP 035. ?2005 NCAT.Snyder, Richard. 2004. Starting Vegetable Transplants. Mississippi State University Extension Service. Publication #P1955.