Evaluating Partial Ridge Venting as a Lower-Cost Passive Ventilation Strategy for High Tunnels in Southern New England

Commodities

• Vegetables: peppers, tomatoes
• Additional Plants: cut flowers

Practices

• Crop Production: high tunnels or hoop houses, season extension, shade cloth
• Education and Training: extension, participatory research, workshop

High tunnels are widely used on diversified farms in the Northeast to extend the growing season, improve crop quality, and increase farm income. However, during late spring and summer, excessive heat and humidity can reduce crop performance, increase plant stress, and create conditions favorable for foliar disease. Ventilation is therefore essential for maintaining a productive high tunnel environment. Roll-up sides are commonly used, but ridge vents may improve passive removal of warm, humid air because heat accumulates near the top of the structure. Full ridge vents can be effective, but their cost may limit adoption by small and mid-sized farms. A lower-cost partial ridge vent could provide a practical alternative, but it has not been rigorously evaluated under Connecticut or broader New England conditions.

This project will evaluate the performance of a partial ridge vent relative to a full ridge vent, shade cloth, and standard sidewall ventilation in two adjacent commercial high tunnels at Echo Farm in northeastern Connecticut. The project will be led by UConn Extension in partnership with the farm and industry collaborators. Over two growing seasons, we will monitor air temperature, relative humidity, solar radiation, and wind, with sensors placed inside both tunnels and outdoors. Treatments will be imposed in a structured schedule so that we can compare how the different ventilation approaches affect daily maximum temperature, cumulative hours above crop-stress thresholds, relative humidity, cumulative hours above 90% relative humidity, and vertical temperature and humidity gradients within each tunnel.

The study addresses a practical question raised by growers and greenhouse manufacturers: can a smaller, less expensive ridge vent provide a meaningful improvement in passive cooling and humidity management without the cost of a full-length system? This is innovative because it evaluates a ventilation configuration not currently documented for New England high tunnel production and tests whether an existing practice can be adapted to a new scale and audience.

Results will be shared through an on-farm field demonstration, Extension meetings, conference presentations, and written outreach materials for growers, Extension educators, and high tunnel service providers. If successful, the project will provide farmers with science-based guidance on a potentially more affordable ventilation option that supports crop productivity, farm profitability, and stewardship of energy and other resources.

Objective 1. Design and install a partial ridge vent with insect screening on one commercial high tunnel at Echo Farm.

Objective 2. Install a full ridge vent with insect screening on the second commercial high tunnel to serve as the benchmark ridge-vent treatment.

Objective 3. Measure and compare the effects of partial ridge venting, full ridge venting, shade cloth, and standard sidewall ventilation on high tunnel air temperature and relative humidity over two growing seasons.

Objective 4. Quantify the ability of each treatment to reduce heat and humidity stress using metrics relevant to commercial production, including daily maximum temperature, cumulative hours above threshold temperatures, relative humidity, cumulative hours above 90% relative humidity, and vertical temperature and humidity gradients within the tunnel.

Objective 5. Share project results with growers, service providers, and industry partners through Extension presentations, an on-farm field demonstration, and written outreach materials so that farmers can make informed decisions about lower-cost passive ventilation strategies.