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-


OUR HIGH TUNNELS are generally : 15 -16 feet tall and 24 TO 30 FT WIDE and up to 100 ft+ Long-


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.

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


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.



Commercial & Code Greenhouse Plans & Kits

We provide Complete High Quality Kits for building both Cold Frames, High Tunnels and Commercial Greenhouses. These Kits are complete and include the Precision Fabricated Frames, State-of-the-Art Hardware; Shading; Cooling & Heating Systems; and a selection Greenhouse Coverings. They are easy to construct either by a licensed contractor or the Owner-Builder with Engineered Plans & full technical support. our designs offer an affordable Solution to Extending your Crop Production.

Stand-Alone SOLAR or Conventionally Powered

Climate Controlled Greenhouses

Yuba County Starstruckture 30ft X 75ft

1. STARSTRUCKTURE GOTHIC ARCH Greenhouses - This system is 30 ft wide, by any length, These systems are made for the serious Gardener; Educational use and for producing Veggie Starts & Plugs for Farm and Commercial Gardens. They are made of 1-7/8" to 2-3/8" gal. American made, Triple Galvanized Structural Steel Tubing. This system is a professional unit that provides maximum growing area for both bench and some types of Container growing systems. These Structures come complete with all parts and many options. The V-Truss System insure strength take snow & wind loads easily. The Roll-Up Sides can be Fully Automatic or Hand Crank Roll-Up Sides. This ensures natural ventilation and you have the also options of Passive Solar or Hybrid Mechanical Vents and Fans. Other options include a tractor sized door, metal end walls sheeted with Twin-Wall® Polycarbronsornate panels. Cooling Systems and much more- If you can think of a Bell or a Whistle that you Do not see here- Just ask us as we and probably have it or we can get it for you (if we believe it works) or offer you an better alternative (if there is one). .This 30 ft wide STARSTRUCKTURE -this Kit is complete, from the Ground Posts to the Cover Film, including all hardware and even the drill bits and nut drivers. If you are having our structure built by as Professional Builder-We offer Complete, professionally drafted Plan Sets & Engineering- If you are building it yourself -or with helpers with carpentry skills- We offer a Complete Installation Guide and Real-Time Assistance. All you need to put this together is someone to help you stand it up, basic carpentry skills, a drill motor, screw gun, ladders and a basic mechanical tool kit. Complete Instructions and Technical help is just a phone call away.

30 footers- . for full production and in the snow


OUR CATERPILLAR TUNNELS (Low Tunnels) are Cold Frames that are basically a series of hoops with hardware to connect the purlins and hold down the covering Greenhouse Film Shade Cloth. We usually build these Kits 14 to 16 ft wide and about 10+ ft tall - depending on your needs. Basic Models can be easily set-up, taken down & moved again to any location. OR you can choose a more permanent build that will be usable for years- some of our Caterpillar Tunnels here at Grizzly Hill Farm are over 20 years old- You can replace your cover to get a longer use to extend the tunnels usefulness. The Sides Roll-up to Ventilate and they can also have Bug-Proof screens under the Roll-up Sides to keep the Pests and Birds out- These houses are easiest to convert to Solar Cooling & Ventilation and can used for Light Deprivation (see Light Depo Model at Bottom of this page).

Slough house Mushroom Farm under construction

Ananda Farm 12 footer under construction



Auto Light Deprivation design for 16 foot Caterpillar



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