By Andi Anderson
Gardeners and growers across the United States have a valuable new tool at their disposal with the recent release of an updated version of the USDA Plant Zone Hardiness Map. This map, essential for making informed planting decisions, now offers a more accurate representation of average annual minimum temperature conditions, thanks to advancements in GIS technology.
Aaron Steil, a consumer horticulture specialist with Iowa State University Extension and Outreach, explains that the map has undergone a notable temperature shift.
It now places more of Iowa in zone 5, a change that reflects an average temperature shift of about one-quarter zone or approximately 2.5°F. This update is significant as it incorporates data from thousands of monitoring stations and is refined by experts in horticulture, botany, and climatology, considering the last 30 years of climate data.
The 2023 map update also stands out for its precision in capturing factors like elevation and large water bodies that influence temperature. Steil advises gardeners to remember that these temperature ranges are averages and that lower temperatures can still occur.
The map's development has evolved significantly since its major revision in 2012, led by Mark Widrlechner, then an affiliate associate professor of horticulture at Iowa State. This update, and the one in 2023, was collaborations with Oregon State University, ensuring a more scientific and repeatable process.
Gardeners and agricultural professionals looking to access the updated USDA Plant Zone Hardiness Map can find it on the USDA website. This tool is invaluable for making precise planting decisions, allowing for a better understanding of plant survival and thriving in varying climatic conditions.
Photo Credit: usda
Categories: Iowa, Government & Policy