Chillin’ out

With the unseasonable weather we are having, there is one subject that I get asked a lot about lately: “Are the warm temperatures going to hurt the trees? Will they start blooming?” Well the answer is no. But that opens up a complicated and fascinating subject.

When a fruit tree finishes its growing season, it slowly enters the process of dormancy as winter approaches. Temperatures play a large role in this. With the warm fall we had this past year this process was delayed for weeks. But once the trees reached the dormant stage, that’s when the chilling begins.

Fruit trees need a certain number of “chilling hours” in order to rest and prepare for the next season. A chilling hour is defined in different ways. Some of the calculating models say that any temps below 45°F count, but others, oddly enough say that temps below 30°F do not count as chilling hours. Still other models begin at 50°F and below and count any hours above 60°F as subtracting from chilling hours. Confused yet? So am I! (and the trees probably are too!) But it is generally accepted to use temperatures between 32°F and 45°F as satisfying the chilling hour standard. And that is the degree range that is tracked by adding up the hours each day during the winter.

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Different fruits, and even different varieties within a fruit type, have different requirements for chilling hours. Most apples need 700-1000 chilling hours to grow and produce properly. There are exceptions such as Gala, Fuji and Granny Smith which need only 400 -600 hours. That is why those varieties are commonly grown in California. Most peaches need 750-950 hours although again there are some as low as 200 hours. Cherries  need 1000+ chilling hours–ever notice that most are grown in the northern U.S.A.?

So what happens if a fruit tree doesn’t receive enough chilling hours in the winter? Well the tree may produce buds with very weak and uneven blossoms, or it may bloom later and over a wide time period. In severe cases the trees may not bloom at all and have a difficult time producing leaves!

Fortunately here in Michigan we have pretty consistent accumulations of chilling hours year after year. The varieties of fruits that we grow are nicely suited to the chilling hour numbers that we see. If you have ever seen a climate zone map such as those put out by nurseries and seed companies, chilling hours are one factor that goes into determining the the different zones. Want to calculate the chilling hours in your neck of the woods? Here is a place to do that.

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So our fruit trees need some time to just chill out in order to recharge for another growing season. Probably a lesson in there for all of us!

Have a fruitful week!

Tom Moelker

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Trimming the trees

It’s a new year, and just like that we go back to winter with a vengeance! But it is, after all, January in Michigan-what do we expect? This time of year things on the farm have slowed down a lot. The holidays are over, the bakery is closed, and we have only a few weeks worth of apples left to sell. So now our focus turns to the annual task of pruning (trimming) apple trees.

There is an old story that when Michelangelo finished his famous statue of David an amazed patron asked “How do you create such a fine work of art?” His answer? “I just chip away everything that doesn’t look like David!” While this story may or may not be true, It comes to mind when someone asks me “How do you know which limbs to cut off and which to leave?” Well there are methods and some rules of thumb to abide by, but some of is just that I kind of know what I want the tree to look like when I’m finished. If I lined up 5 of my fruit growing friends and all looked at the same tree, we probably would not all make the same cuts. That’s because we all have a different picture in our heads of what the finished product should look like!

The older plantings on our farm are pruned in more traditional ways. Free-standing trees, with strong main branches are maintained by removing the yearly “sucker” growth. “Suckers” are  the thin, upright sprouts with no fruit buds on them. Occasionally a large limb is removed in favor of a younger fruiting branch. Outsides and tops are cut back to contain the tree to it’s space and the branches are thinned to let sunlight in. This process is accomplished by riding in a self propelled trimming machine equipped with hydraulic saw and lopper. The driving and moving side to side and up and down are all done with levers run by my feet. This leaves my hands free to use the pruning tools and make the needed cuts. After years of running this machine, I rarely think about the driving part, my feet just do the task subconsciously. Up one side of the row and down the other, hour after hour, day after day.

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Newer plantings are an entirely different animal though. While some of the same principles are applied, These trees will have no permanent limbs. Every year we remove 2-4 of the biggest limbs, leaving a stub that hopefully will send out a new branch the following summer. In this way, the apples are always growing on young, healthy branches and older wood is constantly being replaced. The trees are kept very narrow so that sunlight can penetrate the entire tree from all sides. I’m still getting used to this newer method and it takes a little more thought for me, probably because I’ve been doing it the old way for so long!

So how do I keep from getting bored during the seemingly endless hours or trimming? Well I do have to pay attention to what I am doing, but I often have music or a podcast going in my ears as background noise. My phone is set for hands free calling too, so I can make or answer calls without missing a snip! Technology is great!

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So even during the heart of winter we are trying to …

Have a fruitful day!

Tom Moelker