Summer Solstice is When GDU Accumulation Ramps Up
The summer solstice is the longest day of the year. While many of us celebrate it as the first day of summer, it has even greater significance for the growing season.
June 20 and the summer solstice each year is when most of us start averaging 20 GDUs per day. This period typically lasts 50 days (about 1 and a half months), or until about Aug. 10.
This is the warm part of the growing season and simple math, 50*20, shows this 50-day period accounts for about 1,000 of our season-long GDUs. For those in the north using 80-day hybrids, that’s halfway to black layer. It’s about 40 percent of the season for 100-day growers.
Below are a few graphs visualizing average GDU accumulation per day for each region during the growing season.
If you’d like weekly updates on GDU accumulation, as well as crop conditions and other news, sign up for Swenson’s Snapshot. Click here or fill in the form on the right.
Each week during the growing season, our lead agronomist, Rick Swenson, sends out a regional GDU chart and a few comments about the condition of the crops. The report ends each year with the first frost, or on October 1 – whichever comes first.
At the top of each region/town, you will find the current GDU count for the year and the previous year. The bottom of the page has a graph showing departure from normal. This does an excellent job of showing above and below average progress throughout the season. For each map, we collect reports from our Territory Managers on how the year is rolling along!
As a reminder, our team also created a hybrid cutoff chart, which you can download here.
Each location shows what maturity hybrid you could plant based on the record warmest year, an average year and the previous year. The PDF can be downloaded to use in your office as a quick reference.
Even if your corn is already planted, this tool can help you determine the Growing Degree Units until black layer.
The PDF has 90+ locations throughout the tri-state area. It also has Peterson Farms Seed contact information for a Territory Manager nearest you.
