A hoop house is a simple, arched structure that provides a protective environment for plants. Its primary purpose is to create a microclimate that extends the natural growing season, allowing gardeners to start planting earlier in the spring and harvest later into the fall or even winter. The structure protects crops from environmental stresses like frost, wind damage, and heavy rain, while also deterring certain pests. Constructed from readily available materials and covered with specialized plastic sheeting, a hoop house offers an accessible, low-cost way to enhance garden productivity and longevity.
Planning the Structure and Gathering Materials
Before beginning construction, careful planning of the structure’s placement and dimensions is necessary to maximize its benefits. The ideal site is a flat, well-drained area that receives full sun throughout the day, particularly during the low-light winter months when season extension is most desired. Orienting the structure with its long axis running east-to-west allows it to capture maximum solar gain during the winter and assists with prevailing wind management for ventilation.
The size of the hoop house should be determined by the available garden space and the intended use, keeping in mind that common greenhouse plastic comes in specific widths, often 12 to 24 feet. For the frame, materials include ground posts, such as rebar sections, driven into the soil to anchor the hoops. The hoops themselves are commonly fashioned from PVC pipe or galvanized electrical metallic tubing (EMT), with metal being preferred for its durability.
A wooden base frame, usually constructed from treated 2×6 lumber, is fastened to the ground posts to provide a solid foundation and a secure attachment point for the covering. Securing the covering requires materials like wood battens, snap clamps, or a combination of specialized metal lock channel and wiggle wire, which allows the plastic to be easily tightened and removed.
Assembling the Main Frame
The construction process begins by securely anchoring the perimeter. Rebar sections are driven into the ground along the long sides of the house, leaving six inches exposed above the soil surface. These anchor pins should be spaced uniformly, typically every four to six feet, and angled slightly inward toward the center of the house to help brace the hoops against outward pressure.
Next, the wooden baseboards are laid around the perimeter, and the hoops are formed and installed over the exposed rebar pins. If using PVC or EMT, the pipe is bent into an arch and slid over the rebar anchors on both sides, creating the signature hoop shape. The baseboards are then secured to the bottom of the hoops to create a rigid, rectangular foundation that prevents the hoops from spreading outward under the tension of the plastic covering.
To enhance structural integrity and resistance to wind and snow loads, longitudinal supports known as purlins are installed. A ridge pole is placed along the top center of the hoops, running the entire length of the structure. Additional purlins can be added to the sides, connecting the hoops horizontally to ensure they maintain their shape and spacing. These supports distribute external forces across the entire frame.
Installing the Covering and Access Points
The final stage involves enclosing the structure with the covering, which is a clear, six-mil polyethylene film specifically rated for greenhouse use. This specialized plastic has a typical lifespan of four years and should be draped over the frame. Ensure there is sufficient material to cover the end walls and secure the edges, with extra slack to pull the plastic taut.
Tensioning the film correctly is important for its longevity, as flapping plastic will rapidly degrade and tear. Along the baseboards, the plastic is secured either by clamping it between the wood and an external batten strip, or by using a metal lock channel system with wiggle wire. The wiggle wire method locks the film tightly in place and allows for easy removal and re-tensioning.
The end walls are typically framed with lumber to create a rigid, flat surface for a functional door and to provide a secure anchor point for the plastic. A simple hinged door, or a flap of plastic secured with clips, provides the necessary access. Ventilation is accomplished by rolling up the plastic along the side baseboards, creating a side curtain that allows for temperature regulation and air exchange.