Last week Barbara Roth and Noah Roth (mother and son) of Red Barn Market and Painted Turtle Hard Ciders in Lowell, MI took to Facebook Live to explain something those who manage orchards are keeping a close eye on at this time of year: degree days.
Noah explains: “Degree days are how we measure temperatures in farming. It’s how we know when trees are going to wake up, when bugs are going to come out.”
It’s a degree day when average temperatures get above a certain threshold. For apples, that threshold is 42. They gain a degree day point whenever the average temperature is above that threshold. So if it’s 60 degrees out for 24 hours, they gain 18 points.
There are other factors that affect the calculation of points, namely length of time of the various temperatures, especially the extreme temps. So reaching 42 at night and 52 during the day could net you an average temp of 46, which would mean a gain of 4 degree day points.
Different trees wake up at different degree day points. Macintosh apples are early bearers, and they break dormancy when they hit 127.
This is a concern because, as Noah pointed out on February 26, “Now we’re at 33 degree days. At the end of the week we’ll be over 50. If the forecast holds, we’ll be pushing 100 by the end of next week.” When trees bud and bloom this early, hard freezes will impact the fruit before it even gets going. Noah says, “Every night it gets down cold, we risk our crops.”
While many of us enjoy the record-breaking warm days we’ve been having, farmers with fruit trees are out calculating their degree day points, inspecting their trees, and making plans to bring out the big fans when it gets cold. And, as Barbara says, “We’re going to keep praying that we have what we need for weather for this season.”
In the video, Noah talks about the different stages of buds, and demonstrates some pruning, so watch the whole thing to learn more about managing an orchard. https://www.facebook.com/100063596287356/videos/1479240566323261 Noah also recommends this video for explaining how wind machines can help during an ill-timed freeze: https://youtu.be/6G0J6CdqkrI?si=YcYfV6hXZLp3-Grh
Thank you to Noah and Barbara for sharing your expertise!
