Urban Roots Farm is a four season farm, meaning we grow, and market fresh produce every month of the year. We are able to do this despite the temperate climate of Southwest Missouri thanks to our three mobile high tunnels.
High tunnels are clear plastic covered structures with frames made from various materials. They are constructed in almost any size configuration you can imagine. Some are stationary, and some are movable. Ours are steel framed and measure 30 feet by 48 feet. They rest on cantilever gate rollers, like you would see on big chainlink gates, which ride on galvanized tube rails. The high tunnel field is divided into nine growing spaces which are each 30 feet wide and 48 feet long. At all times each tunnel covers one of the three growing spaces which are in line with it.
The daily cycle
During the day, the sun strikes the surfaces within the tunnel, such as foliage, and soil. The heat which radiates from those surfaces is accumulated within the tunnels, and the temperature inside rises well above the outdoor temperature. On a sunny winter day it is common for the temperature in the tunnel to be 40 to 50 degrees higher than that outside the tunnel. When the sun goes down the air temperature in the tunnels rapidly drops to the outdoor ambient temperature, but the plants are still protected from the wind and moisture they would be subject to in the open. Over night the crop foliage often freezes but the root zone stays warm. When the sun rises again so does the temperature in the tunnel. The foliage thaws, and the plants grow on.
The seasonal cycle
The tunnels are moved around the field at stratiegic times throughout the year in order to allow us to extend our growing season. In late winter we trust hardy vegetable crops to the protection of the tunnels one to two months before we could safely plant them outdoors. When the outdoor temperatures have risen sufficiently, we move the tunnels off the hardy crops, and plant the newly covered growing space with regular season crops a month or so before typical outdoor planting times. When those crops no longer require protection the tunnels are moved again to cover warmth loving crops such as melons, cucumbers, and tomatoes. The tunnels remain in this third position late into the fall, pushing summer crops as late as possible. When the third position crops are no longer productive, we move the tunnels one last time to cover super hardy crops such as various greens, and root crops through the winter. In late winter it all starts again.
Come by the farm any time for a real world demo.