HOOPHOUSE CONSTRUCTION
FACTS AT A GLANCE

  • SKILL LEVEL TO BUILD - A single-bay (one hoop) unit requires minimal construction experience. Multibay units (hoops or tunnels share common walls) require significantly more construction skills. The critical part of construction is ensuring the ground posts are spaced as perfectly as possible, so that the other pieces of the "tinkertoy" will fit properly.

  • COST - Unheated greenhouses cost roughly $3 to $5.50 per square foot, though volatility in the prices of steel and the oil-based polyethylene make it difficult to predict future costs.

  • SITING - For winter production in northern states, east-west siting gives the greatest exposure to the sun. Shading or shadowing from buildings or trees can require north-south siting, but research suggests this configuration can still be productive in winter months.

  • BUILDING PERMITS - Though state and local laws vary, in general, if a hoophouse is not cemented into the ground, it is considered a temporary structure. Temporary structures usually do not require a building permit, but check with your local zoning authorities.

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GROWING FOOD

ALL ABOUT HOOPHOUSES featuring unheated greenhouse specialist Adam Montri of Michigan State University

Adam Montri and his friends build an unheated 34 by 96 foot greenhouse at his Ten Hens Farm in Bath, Michigan. The first two videos below offer information on building the hoophouse. The final three videos feature Adam in the completed hoophouse offering tips on everything from watering crops in winter to marketing directly to consumers.

Building a Hoophouse: Part 1 - The skeleton

 Gardeners and farmers alike are exploring the benefits of erecting "hoophouses," unheated passive solar greenhouses that can be used for winter production of vegetables in northern states.

Hoophouses, also called high tunnels, are typically constructed with steel hoops covered in 6-mil polyethylene. Endwalls are polyethylene film or polycarbonate, which is more expensive but lasts longer. You can also buy hoophouses that are all polycarbonate, but most growers find the cost prohibitive on large structures.

The videos at the left offer information and advice from Michigan State University unheated greenhouse specialist Adam Montri, whose position is funded in part through USDA's National Research Initiative program on Agricultural Prosperity for Small- and Medium-Sized Farms.

FREE DOWNLOAD FROM MSU - Year-Round Vegetable Crop Production Schedule - Click here for aPDF handout created by Adam Montri that is tailored to Michigan's climate.

So what the heck is a purlin?A picture of a hoophouse under construction with the pieces tagged

  • Ground post - These are the posts you drive into the ground that support the entire structure. The bows slip onto them, so they must be spaced perfectly for the rest of the construction to go smoothly.
  • Bows - These are the hoops that hold up the plastic and support the endwalls. After setting the ground posts, two or more people "stand up" the bows and place them onto the ground posts.
    • Trusses - These are the steel tubes that help hold the bows in place. Some hoophouses do not use trusses.
    • Ridge cap - A peaked hoophouse has a ridge cap along the top. Hoophouses without a peak obviously do not use a ridge cap.
  • Purlin - After the bows go up, purlins are the pipes that hold the bows in place and add stability to the structure.

Send us your questions - We will gather them, ask Adam and post answers here or in our Sustainable Farmer Forum.