Photo by Rachael Brugger Although for years farmers have been growing other crops in high tunnels to extend the growing season, they are now finding the benefits to growing brambles in them, as well.

Since about the early 2000s, farmers have tried planting berries in high tunnels, and this technique is gaining in popularity. Cathy Heidenreich, berry extension-support specialist for Cornell University, says the high tunnels extend the growing season more economically than using greenhouses.

Typically 15 to 30 feet wide, 60 to 96 feet long, and 7 to 15 feet high, high tunnels allow for the production of fall-bearing brambles in climates with a short growing season. Researchers at Penn State’s Center for Plasticulture have found that brambles grown in high tunnels show “tremendous yield increases over field production” with fall-bearing raspberries, producing a crop two- to three-times larger than those not grown in high tunnels. This is due to the extension of the harvest by at least three weeks.

Additionally, high tunnels allow for “less hardy bramble varieties to overwinter in climates where they would otherwise be killed,” according to Heidenreich. Healthier plants and fewer pests are two additional benefits to growing brambles in high tunnels.

For all of their positives, high tunnels do have a downside: They get hot, requiring constant temperature monitoring. Researchers are experimenting with different plastics to find one that will provide a better temperature in the high tunnel. Until something is developed, however, the grower needs to provide good ventilation inside the high tunnel and be available to manually adjust the temperature as needed. Also, because the brambles are sheltered from the rain, using tunnels requires that the grower have a relatively large source of water and an efficient irrigation system.