I figured I would share this experiment with the forum incase anyone else is like me.

I love the look of Japanese Maples, but I live in an area with a climate that easily kills Japanese Maples. We often get 1-2 months of -20 to -40. My unheated garage is usually about -10 inside when its -20 outside, but when we hit -30 to -40 even the temp in my garage would likely kill one.

This summer when I was at the nursery I saw they brought in a bunch of Maples. I looked at them with sorrow, both because they are beautiful and ill never be able to raise one, and secondly, because all of them were likely condemned to death when they were shipped to Winnipeg. I gave in however, and did something foolish. I dropped $80 on one.

I figured I'd find a place to put it over winter. Well, that place is a Danby mini fridge.

So far Ive left it outside from Summer until we got an evening of -14°c (forgot to bring it into garage that night). After that it's only seen a low of about -12°c and sat around -5 to 0. I'm not sure if the one evening of -14°c would have been enough to kill the roots but I guess ill see in the Spring.

If it doesn't work this year ill assume maybe I let it get too cold and ill repeat with a palmatum (This guy is a dissectum). Anyways, ill keep you guys updated on my experiment.

Ill update this thread with what temperature range the fridge is operating between

be carefull with fridges. Your tree might dry out a lot.

I doubt the cold is the issue with your maples. But, if you do worry, I would consider making a sandbed to put the pot on. Have a heater cable burried in the sand on a temperature trigger which you trip whenever your garage drops below -10c. You are correct in assuming it is the roots that needs most support.

Maybe put a themometer in the garage and monitor the temp profile?

Honestly, sometimes we get days as pictured below (-40°c) and I felt it would be easier to keep the temperature range livable inside the fridge because its designed to do so.



Wasn't as confident in my skills in building an apparatus of my own design in order to combat the variables above. Not that it couldn't work better than the fridge, I just don't believe one designed by yours truly would be as safe or effective.

I am kind of worried about the tree drying out though. Do you think it could help to place it in a garbage bag inside of the fridge?

Anyways, I am only two years into Bonsai, and I am new to deciduous trees. Weighing which poison I wanna choose, risk of acute freezing v.s. chronic dryness. Thanks for your interest. I am open to any and all criticism or comments, and appreciate the knowledge!

that is ff cold indeed.

I think putting it in a plastic bag could help. But.. not sure. tbh, it does not get that cold here, so I am cltching at fundamentals, rather than personal experience. Have you tried reaching out to a local bonsai club? They can probably recommend how to go about based on their own experience.

Do you keep the tree at around 3celcius and 10% humidity, like the picture shows us? Did i read that right?
I would try to keep the humidty around 45/55%, otherwise the air is to dry.

You can/could keep the roots/soil warmer at around 7c, then the roots continue to grow. Then keep the area around the tree cooler so it stays dormant, the 3celcius would be ok.

non bonsai
The proffessional growers here in the neighborhood, keep there unsold fruittree's, strawberry and other plants in freezers at -1/0/1, when there not sold in that season. Then for the entire spring/summer there in the freezer. So they can try to sell them again when the next season starts. Those plants are kept bareroot, without soil.

That is some extreme cold and sounds miserable.
Something that I have seen before is burying the tree's pot and trunk up to the first branch. If you did this in a slightly enclosed space where your tree is protected from the wind that may help with drying out as well. I am far from an expert on this but it is a thought...