Quantifying How High Tunnels Create a Microclimate For Improved Crop Growth

Abstract

Farmers in the Great Basin are investing in inexpensive low-tech greenhouses, known as high tunnels (HTs) or hoop houses. This study evaluated the microclimate inside HTs, how farmers were using HTs to grow crops and how the microclimate inside HTs led to improved crop growth. The HT microclimate varied by season, with more growing degree days inside the HT than outside in the spring, fall and winter. The way farmers managed HTs using manual ventilation, shade cloth and fans was the strongest determinant of how the climate inside the HT was different from outside. HTs increased vapor pressure, leading to potentially less need for irrigation water. By creating microclimates suitable to crop growth, farmers were able to extend the growing season, grow a wider variety of crops and improve yields. HTs improved the economic viability of farms for farmers who had been using them for several years. HTs in the high desert are only increasing in popularity and farmers are continuing to use and recommend them to other farmers.