With the early arrival of warm weather comes earlier blossoming of the area's fruit trees, and increased risk of losing crops to a freeze. One local family is trying a different method of protecting their crops from freezing temperatures and killing frost this spring: The "cold air drain."
"The data is still out," said Andrew Thliveris of the new cold air drain system being tested in a block of cherry trees on Mathews Lane. They've run the system, an elevated, multi-sided green metal box with a large gas-powered engine mounted next to it, twice this season, including Monday morning when temperatures dipped into the high 20s.
The Thliveris family has grown fruit in the Paonia area since 1943. Last summer they opened Berg Harvest Mercantile, a seasonal market where they sell their fresh fruits and other local goods, on family land across from the Paonia Library. Weather patterns are definitely changing, said Thliveris. "Talk with the old farmers and they'll tell you they always had a cherry crop," he said. "Now it's the opposite. Everybody's scrambling."
Thliveris said they are working to keep up with state-of-the-art and low-cost methods of protecting their crops from frost damage. The cold air drain is "another technique in our repertoire."
In theory the system should work well, said Thliveris. There's a lot of science behind it, including research by Colorado State University dating back to the 1960s. The company that designed the system, Shur Farms Frost Protection, states on its website that more than 20 years of experience are behind the technology.
Thliveris explained that engineers start by creating a map of how cold air flows through the orchard, and where pockets of cold air can accumulate. Cold air barriers are then placed around the orchard to keep cold air from migrating in from surrounding areas, and heaters or fires are placed throughout the orchard. As the system runs, it draws cold air from the bottom two or three feet of the orchard up and disperses it into the atmosphere where the air is warmer. In doing so it creates low pressure near the ground. As the cold air mixes with warm air above, the low-pressure system draws the warmer air back into the orchard.
The system can also be used in conjunction with propane heaters, small fires, and orchard wind machines. The unit is also cost effective, since it is gas powered and costs just a few dollars a night to run, said Thliveris.
In order to measure the effects of their systems, they are collecting data on temperature variations in orchard blocks with and without any frost protection measures and comparing the data, said Thliveris. In the meantime, they are doing everything they can to protect their crops and keeping their fingers crossed.