We all know heat and hail damage potatoes, but when these stresses occur may be more important than their intensity. This is the key finding from ongoing research by Jonathan Neilson at Agriculture and Agri-Food Canada’s Lethbridge Research and Development Centre. By simulating the warmer-than-usual May and June conditions experienced in Alberta in 2021 and 2023, Neilson’s team has identified a critical “susceptibility window” in the middle of the growing season. Their work shows that stresses experienced very early or late in the season often result in a delay of one to two weeks, but plants can largely recover yield. However, stress during the mid-season period leads to significant, irreversible damage to tuber quality and marketability.
The economic impact of mid-season stress is severe and manifests in specific, costly defects. Heat stress can cause “heat runners” (knobby deformations) and “sugar ends” or “jelly ends,” a condition where sugars accumulate at one end of the tuber instead of converting to starch. This defect is a major issue for the processing sector, as it results in unevenly colored French fries that are often downgraded or rejected. Similarly, hail damage during this sensitive period can disrupt tuber bulking, leading to “double sets” – a non-uniform mix of oversized and undersized tubers that complicates packing and reduces the percentage of high-value sizes. These quality issues directly hit a grower’s bottom line. A 2022 study in the American Journal of Potato Research corroborates that pre-conditioning and recovery potential are highly dependent on growth stage, emphasizing that tuber initiation and bulking are the most critical phases.
This research provides a powerful, actionable framework for the potato industry. Instead of viewing weather stress as a uniform threat, growers, agronomists, and farm managers can now focus their risk mitigation strategies—such as irrigation management, hail netting, or crop insurance decisions—around a clearly defined period of peak vulnerability. The development of a practical risk assessment tool will be invaluable for making informed business decisions in real-time. Furthermore, the planned investigation into biostimulants and soil health promises to provide proactive solutions for building crop resilience. Ultimately, this work shifts the paradigm from reactive damage assessment to proactive, calendar-based risk management, empowering producers to safeguard both their yield and their profitability against an increasingly volatile climate.
