High TunnelS

1.What is a High Tunnel?
A High Tunnel is a solar heated greenhouse 'Usually' with no electrical or automated ventilation that is used to extend the crop production season for many horticulture crops. Crops that are produced within high tunnels are grown in the ground or in raised beds with drip irrigation. Greenhouses are heated systems that have foundations & are energy dependent whereas a High Tunnel utilizes Passive Solar.

2. Do I need to have a building permit for my High Tunnel?
High tunnels are considered to be impermanent structures and protected under the "Right to Farm Act." Nevada County has determined that no permit is needed for farmers installing a High Tunnel.
3. How does a low tunnel differ from a High Tunnel?
In a nutshell, you can stand upright in even an inexpensive high tunnel, but low tunnels are too short. Basically, low tunnels can be constructed by placing wire hoops, spaced 3-5 ft apart and about 4.5’ high at the apex, over a row of crop to provide additional protection from the cold.
4. 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.
5. 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 if you are going to"force Flowering". 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, 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.

6. 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.