Cherry Cold Requirements: How Many Chill Hours For Cherries
A few years ago I was asked to write a post about cherries. At first I thought it would be some kind of recipe or something like that, but then when I started writing the idea just came naturally. So here it is; my take on how many chill hours are required for cherries.
(I’m not going to say exactly what they are because there’s no such thing as a “right” number)
The reason why I wrote this post is because I’ve been trying to figure out how much time it takes to grow cherries and if I should go with a cold frame or not. My original plan was to do this in one year, but now that I have a bit more experience, it seems like the best way would be two years. That means that after the second year, I’ll probably start getting ready for winter so that’s when my cold frames will begin.
So let’s get into it shall we?
How Many Chill Hours Are Required For Cherries?
As you may already know, there are different types of cherries. There are those that require less chill hours than others. These include:
Lapin – these don’t need any at all, because they’re grown in their natural state. They’re called lapins because they look like little lobsters!
Tilton – these ones need about 300 hours. Don’t let the name fool you, they’re not from Tilton, Massachusetts but rather from New Jersey where they were first bred in 1953.
Sterling – these ones need about 500-550 hours. They’re also called Palmos and are bred at the Longenecker Horticultural Farm. They’re actually a crossbreed between a Van and another unknown type of cherry.
Royal – these ones need about 550 hours too. They’re also called Bearss and are from the University of Florida where they were created in 1956.
Van – these ones need about 1000 hours. They’re the classic ones and probably what you think of when you think of cherries.
How To Increase Those Chill Hours?
So you’ve decided on a certain type of cherry, but it needs more chill hours than you want it to. Well, lucky for you, if you live somewhere with a lot of snowfall in the winter, you can actually build something called a cold frame to protect your plants. This is really easy to do. All you need to do is build a box out of wood and put a glass cover on top of it. This way your plants will get the extra protection they need during the winter. I usually make mine about 2 feet by 4 feet and stack straw bales around the outside for extra insulation. You can also put a wax paper or plastic roof on top instead of glass for extra protection from the rain.
Of course if you don’t get a lot of snowfall, you can always just increase the amount of hours that you keep your plants in your basement. Just move them down there when the temperature starts to drop and move them back up when it starts to rise again. If you have more than two plants, then this method is probably going to be impractical though because your parents are probably going to start getting suspicious of all the extra junk taking up space in the basement!
Finally, there’s always the option of taking your plants to somewhere with a higher chill hour requirement for a short period of time. I’ve heard of people who have taken their plants camping with them in the mountains where the chill hours required are much higher. Of course this isn’t really an option for most people due to the fact that they either don’t own a camper or have the time off work.
Well, I hope this helps you make up your mind on the type of cherries that you’re going to go with!
Tune in next week when I’ll talk more about planting!
Sources & references used in this article:
Chilling requirements of sweet cherries (Prunus avium) and interspecific cherry hybrids (Prunus x ssp.) by S Seif, W Gruppe – … of Sweet and Sour Cherry Varieties and Rootstocks …, 1984 – actahort.org
Identification of chilling and heat requirements of cherry trees—a statistical approach by E Luedeling, A Kunz, MM Blanke – International journal of biometeorology, 2013 – Springer
Cherry growing in the subtropics by AB Küden, A Küden, N Kaska – V Temperate Zone Fruit in the Tropics …, 1996 – actahort.org
Chilling requirements of cherries grown under subtropical conditions of Adana. by AB Kuden, B Imrak, S Bayazıt… – Middle East Journal of …, 2012 – cabdirect.org
Chill unit models for the sweet cherry cvs Stella, Sunburst and Summit by K Mahmood, JG Carew, P Hadley… – The Journal of …, 2000 – Taylor & Francis