Beat the Heat: Protecting Northern Highbush Blueberry from Extreme Heat

Extreme heat is an increasing threat to Washington’s blueberry industry, affecting both yield and fruit quality. This publication explains how high temperatures damage blueberry flowers and fruits by disrupting pollination, impairing photosynthesis, and causing direct injury to plant tissues. It describes temperature thresholds linked to reduced pollen viability, impaired fruit development, and visible damage to leaves and berries. The project analyzes historical heat-stress exposure across blueberry-growing counties and projects future risks through mid-century using climate-model ensembles. Spatial analogs identify regions whose current climates resemble Washington’s future conditions, helping growers anticipate and prepare for changing heat patterns. The publication also reviews mitigation strategies—including evaporative cooling, shade nets, and emerging biostimulants—highlighting their benefits, limitations, economic considerations, and potential impacts on pollination and disease. This information equips Washington growers with science-based guidance to reduce losses and adapt production systems to rising heat stress.