Elevated Greenhouse

Updated: 2026-07-21

Overview

High tunnel greenhouses, also known as hoop houses, are unheated structures that create a controlled microclimate for plants. Unlike traditional greenhouses, they rely on passive solar heating and natural ventilation. Their simple design makes them affordable for small-scale growers while still providing significant production benefits. First developed in the 1950s, modern high tunnels have evolved with improved materials and engineering. They typically stand 12-15 feet tall at the peak, allowing for adequate air circulation and equipment access. The arched shape sheds snow effectively while maximizing light penetration throughout the day.

Structure and Working Principle

The basic structure consists of metal or PVC bows anchored into the ground, forming a series of arches. These are connected by purlins for stability and covered with a single or double layer of polyethylene film. The ends can be left open or fitted with roll-up/door systems for ventilation control. The working principle relies on the greenhouse effect - sunlight passes through the transparent covering, warming the interior air and soil. At night, the trapped heat extends the growing season by protecting plants from frost. Proper ventilation prevents overheating during the day and regulates humidity levels.

Key Features

Modern high tunnels incorporate several important features: UV-stabilized polyethylene films that typically last 4-6 years; roll-up side ventilation systems for temperature control; and insect netting options for pest management. The structures are designed to withstand wind speeds up to 70 mph when properly installed. Additional features may include automated ventilation systems, supplemental lighting, or irrigation systems. Many models offer customization options for height, width, and covering materials to suit specific crop requirements and local climate conditions.

Application Areas

High tunnels are widely used for season extension of high-value crops like berries, tomatoes, and leafy greens. They enable growers to start planting 4-6 weeks earlier in spring and continue production 4-8 weeks later in fall. Organic producers particularly benefit from the reduced pest pressure and ability to grow without synthetic pesticides. Other applications include nursery production for ornamental plants, overwintering of perennial crops, and protected cultivation in areas with excessive rain or wind. Some growers use them for hardening off seedlings or protecting delicate crops during critical growth stages.

Maintenance and Precautions

Regular maintenance includes inspecting the structure for damage after severe weather, cleaning the plastic cover to maintain light transmission, and ensuring proper tension in the covering material. The plastic should be replaced before it becomes brittle or develops significant light-blocking scratches. Important precautions include proper site selection (good drainage, full sun exposure) and adequate anchoring. In snowy regions, the structure must be strong enough to handle snow loads, or the snow must be removed promptly. Proper ventilation management is crucial to prevent disease outbreaks in the humid environment.

B2B Procurement Guide

When procuring high tunnels commercially, consider ordering multiple units simultaneously for volume discounts. Many suppliers offer package deals including structure, cover, and installation services. For large-scale operations, customized designs with reinforced frames may be worth the additional investment. Key procurement factors include: local building codes and permit requirements; availability of replacement parts; warranty terms (typically 5-10 years on metal frames); and supplier reputation. Many agricultural extension services provide free planning assistance and can recommend reliable manufacturers.