California pistachios now cover more than 600,000 acres and generate over $2.5 billion annually. As demand for pistachios continues to grow worldwide, production remains concentrated in the Central Valley with some acreage in coastal counties. However, a changing climate is creating new challenges for growers.
Although the 2025–2026 winter felt “normal” with cold, foggy days, a closer look at the data shows that some pistachio orchards may not have received adequate winter chill. The March heatwave, which coincided with bloom, further intensified bloom and nut-set irregularities, issues many growers have already reported. However, some orchards were severely affected while others showed little or no impact, pointing to underlying factors that are not yet fully understood.
This situation presents a valuable opportunity to better understand how unseasonable weather affects bloom, fertilization and set. To this end, the University of California, Davis (UCD) and the California Pistachio Research Board (CPRB) have developed a short grower survey. The information collected will help researchers evaluate the impacts of climate variability during this critical developmental stage. Several CPRB-funded research trials focused on improving yield and quality may also benefit from the survey data. These findings will help researchers develop strategies to prevent or mitigate similar impacts in the future and identify priority areas for targeted research. Grower participation is essential: the more orchards represented, the clearer the picture will be for guiding future research and management decisions.
The California Pistachio Research Board encourages growers to complete the survey and share observations from their orchards this season. Growers with multiple orchards showing different performance under the same cultural practices (e.g. irrigation, fertilization) are welcome to submit separate responses for each site. The survey takes only a few minutes to
complete but will provide valuable insights for future research.
All responses are anonymous unless you choose to provide contact information. Growers can use the link or QR code below to access the survey.
Pistachio Survey: https://forms.gle/vyeXgnoGfYG3aDDQ9