Lincoln University Low Tunnel Workshop Demonstrates Row Covers, Hoops and Seasonal Practices

Protecting crops requires thoughtful planning and attention to seasonal changes. This February, Lincoln University Cooperative Extension (LUCE) brought aspiring and experienced growers together for a Low Tunnel Workshop focused on practical crop protection strategies. Held at Finca EcoFarm, a garden demonstration site on campus used for hands-on education, the session examined how row covers and hoops work together to create a low tunnel.

"There are three main reasons why we want to use a low tunnel - to protect from frost, to protect from bugs and to protect from the sun," said Mary Keeter, who led the workshop and works as a regional outreach worker with LUCE's Innovative Small Farmers Outreach Program.

Built using hoops and materials such as row covers or netting, low tunnels form a low-profile structure that helps protect crops from changing conditions. They can be adapted for use in a range of growing settings, including in-ground plantings, raised beds and greenhouse production.

Participants examined several types of row covers and netting during the workshop. Keeter noted that lightweight row covers are commonly used for frost protection, helping trap a small amount of heat near crops during cold nights. Heavier row covers offer additional insulation but reduce airflow, making material choice more important as temperatures change.

Mary Keeter shows how hoops support row covers to create low tunnels for crop protection.

Rather than using the same covering throughout the season, Keeter emphasized selecting materials based on weather conditions and crop timing.

For example, shade cloth can be used in high temperatures to protect crops from excessive sun and heat. Unlike frost fabric, which is secured to the ground to trap warmth, shade cloth is kept elevated above plants so air can circulate.

Low tunnels are also used to reduce insect pressure, particularly during early growth stages when plants are more vulnerable. Secured insect netting helps keep pests off crops, but the material must be kept off plants to be effective.

"If the netting is touching the plant, insects can still lay eggs," Keeter told participants. "That's why the hoops matter."

Keeter added that when row covers rest directly on plants, they can transfer cold during chilly conditions or trap heat during warmer weather, increasing the risk of crop damage. Using hoops keeps the material lifted, creating air gaps that allow the covers to function as intended without stressing plants.

During the workshop, participants explored several hoop options used to support low tunnels, including both pre-bent hoops and materials that can be shaped on-site. Pre-bent wire hoops offer a ready-to-use option for standard bed sizes and are often used when a quick setup is needed.

Participants take turns bending metal conduit into hoops during the live demonstration.

For growers seeking more flexibility, Keeter discussed do-it-yourself hoop options made from wire, PVC and metal conduit. These materials allow hoop width and height to be customized based on crop growth and bed size. While lighter materials can work well for short-term use, sturdier options such as metal conduit provide greater stability, hold up better in windy conditions and can be reused across multiple seasons.

Following the overview, Keeter led a live demonstration showing how straight lengths of metal conduit can be bent into hoops using a hoop bender. She advised not to overbend, as it can affect how the hoop fits into the ground. Participants assisted with the process, gaining experience shaping and adjusting the hoops.

Community member Brionna Wade attended the event with her two sons and emphasized the importance of providing learning opportunities beyond a traditional classroom. Because her sons already enjoy gardening, she said applied experiences like the workshop are especially valuable. During the demonstration, the boys helped bend a metal conduit hoop, and Wade said the techniques shared offered ideas she plans to use at home.

The workshop concluded with participants receiving materials to build their own low tunnels, including hoops and row covers sized for a 4-by-8-foot raised bed. Keeter encouraged attendees to adapt methods to their own growing spaces and highlighted that Extension support continues beyond the workshop.

"Feel free to reach out," she told participants. "We can work together and make it happen."

As part of the workshop, community garden participants were invited to apply low tunnel techniques in their assigned raised beds to help extend the growing season.

Support for growers continues through LUCE's Innovative Small Farmers Outreach Program and the Native and Specialty Crops Program, which collaborated on the creation of the Low Tunnel Workshop.

The Innovative Small Farmers Outreach Program provides hands-on training and technical support to small farmers and urban growers across Missouri. For more information, contact Mark Lucas at [email protected].

The Native and Specialty Crops Program, which operates Finca EcoFarm, also supports the on-site community garden. As part of the workshop, community garden participants were invited to apply low tunnel techniques in their assigned raised beds to extend their growing season. For more information about the community garden, contact Nadia Navarrete-Tindall at [email protected].

For more information on low tunnel systems, visit this USDA resource here.

USDA example of an in-ground low tunnel in action.