WHAT IS A HIGH TUNNEL?
A High Tunnel is a solar heated greenhouse 'Usually' with Only Passive Automated ventilation that is used to extend the crop production season for many horticultural crops. Crops that are produced within high tunnels are grown in the ground or in some cases raised beds with drip irrigation.
OUR AGRICULTURAL HIGH TUNNELS are Engineered Gothic Arch Structures made from Galvanized Steel Frames- Our Structures utilize Passive Solar Power and Appropriate Tech to maintain a productive Growing Environment - whereas a Greenhouse utilizes Solar or Fossil Fuel for Energy. In most instances- both are used efficiently as possible-
SIZES OF OUR HIGH TUNNELS
OUR HIGH TUNNELS are generally : 15 -16 feet tall and 24 TO 30 FT WIDE and up to 100 ft+ Long-
SIZES OF LOW & CATERPILLAR TUNNELS
OUR LOW TUNNELS are 14 ft to 16 ft wide X Whatever Length -OUR CATERPILLAR TUNNELS are Low Tunnels and are usually 12 ft to 16 ft wide x Whatever Length you want. These are ALL 8 to 12 ft at the peak of the Bend- Depending on the Model.
How does a LOW TUNNEL differ from a HIGH TUNNEL?
LOW TUNNELS do not require a foundation- the Ground Posts are Driven; Augured or Pounded into the earth- You can use a bit of concrete or sand but it is not necessary.
ENGINEERING & OTHER REQUIREMENTS Generally, Footings or even a foundation (for some Code installations) may be REQUIRED- Stamped Engineering for your APN # (is available from our site engineer for a separate fee). Engineering is Not required for NRCS High-Tunnels). Building Instructions and Plans are always included with all of our KITS.
BOTH will shed snow well- if price is a consideration then the LOW TUNNEL or the CATERPILLAR will work well.
If Usable Square Footage is important to you- then the HIGH TUNNEL is best!
HIGH TUNNELS are best for installing additional systems - such as Heating; Cooling; Benching; Light Deprivation or other of the many peripheral products and systems that are available- depending on your needs.
NRCS HIGH TUNNELS
High tunnels are considered to be impermanent structures SYCH AS A COLD FRAME and protected under the "Right to Farm Act.". These structures can be funded by the USDA for approved Certified Agricultural Producers (see our NRCS HIGH TUNNEL page in the Navigation Bar above - for more information!
Where should I place a High Tunnel on my farm?
A High Tunnel should be placed on a level, well-drained, accessible site. BUT, many choose to build their High Tunnels on a slope or grade.
Should I grow vegetables in a Greenhouse or a High Tunnel?
Energy & Input costs for a Climate-Controlled Greenhouse vegetable production are significantly higher relative to High Tunnel vegetable production. High Tunnels utilize Natural Ventilation and Passive Solar to Cool and Heat.
What is the optimal orientation for a high tunnel?
Unlike greenhouses, orienting a High-tunnel for sunlight is not as crucial as long as the the High Tunnel gets ample sun. Although having the long side facing south is best. In a windy location a High Tunnel should be oriented in a direction that faces the Endwall toward the prevailing winds
BE SURE TO NEVER LEAVE THE DOORS OPEN ON WINDY DAYS!
Remember, with a NRCS HIGH TUNNEL all ventilation is manual, or passive solar- so you depend on the wind to ventilate your house. In the Foothills, our winds are predominantly from the North -Northwest. Thus, for spring tomato production, we find an North-South orientation to be optimal.
Can a High Tunnel be movable?
Yes. One of the primary objectives of a high tunnel is to expand the harvest
period. our Cold Frames are the best solutions for building a movable system. However, movable High Tunnels are moved on to existing plots of land to accelerate growth or extend the growing season for that crop. However, relative to stationary High Tunnels, they are less airtight. Consult Eliot Coleman’s Winter Harvest Manual for additional information on design of movable high tunnels.