Mist-cooling to delay bloom and prevent frost damage- old idea new technology

Abstract. In contrast to the majority of the world’s major food crops in which the primary climatological production constraint is the amount and timing of precipitation during the growing season, the primary weather-related constraint for most temperate tree fruit crops is the frequency and severity of spring freeze events. In Great Lakes region, the frequency of spring freeze events following initial phenological development has increased during the past few decades. Michigan's tart cherry and apple production in 2012 was reduced by about 90% and 88%, respectively, compared to the previous year’s production due to a series of spring freeze events. The onset of phenological development in the spring is a key factor in determining potential cold damage risk, as the vulnerability of vegetation to freeze injury increases rapidly with the stage of development. Evaporative cooling with water prior to bud break has been used in the past (mid 70’s and early 80’s) to delay early development of flowers; one to three week delay was observed. However, related problems (more disease, poor fruit set, and large applications of water) reduced its potential for commercial use. This study re-examines the mist-cooling to delay bloom by adapting solid set canopy delivery system (SSCD), as environment friendly climate change adaptation method. Also, the study estimates the heat transfer in buds, timing and volume of mist required. In 2013 and 2014, Misting delayed the bloom by 5-11 days in apple with the mist application of 11-14 cm/ha (2013) and 14-15 cm/ha (2014).