Damaging Temps?

[shohin_branches]

I guess I'm sorry that Michael Hagedorn disagrees in his book about unheated hoop houses in Japan. I live in Va. in a completely different climate with completely different conditions and tree species. I have been overwintering bonsai for a very long time. What I do works and works well.

Sorry, I didn't explain my point very well. I wasn't saying to change how you overwinter, just that temperatures around freezing aren't more dangerous than keeping the plant solidly frozen.

Now that more advanced temperature monitoring is cheap and easy for anyone to purchase I've been surprised at what temperatures my trees actually experience in winter storage. I've been navigating overwintering in Wisconsin since 2000, mostly living at rentals without garages so now that I own a house finally I'm trying to refine and keep the process a little more polar-vortex proof.

My greenhouse fluctuates temperatures wildly throughout the day and it stressed me out so much last year to watch the swings. I only lost one trident maple sapling and I assume it was from the greenhouse getting down to 11°F when the heater couldn't keep up during a -10°F day.

These are the temperatures in that greenhouse (just using it for winter sowing this year so no heater and the auto vent is broken) with max temperatures being 96°F and min being 16°F. It only gets about two hours of partial sun a day. Not even full sun.


I just got the sensor set up for my shed on Friday so I don't have much data yet. The cedar shed is much easier to keep a stable temperature already even with the greenhouse panels on the east side of the roof, but the heater is not strong enough to handle the really cold days in such a large space.

Temperature fluctuations are normal day to day so I'm trying to unlearn panicking if they are freezing and thawing. Now I'm focused on buffering the trees from hitting the extreme cold and focusing on continuing my water check schedule.

 

[queenofsheba52]

I am also trying to unlearn panicking. Not just about my trees, but about many things.

 

[jimlau]

Ok, so if low 40s in the day and high 20s at high for 1-2 weeks, the trees can be watered safely? They are mulched, and most of the roots in the ground.

It's been a few weeks without water.

 

[Deep Sea Diver]

Seems best to ease back and count on the media moisture to tell you when to water.

Ignore the temperature signals unless they force early budding… even then that’s a signal to shelter not water. Media moisture tells all.

Trees need to be watered in dormancy when the media is near dry, before a hard freeze and after a hard freeze... A decent rainfall and snow melt count. Fell the media. We don’t use chopsticks, but it can be a very useful tool when one first starts out.

For our greenhouses that means water every 2-4 weeks. Cold frame mulched in - rarely. Dug in under trees - rarely. On the bench, a bit more often, especially during dry sunny spells… yet still measured in weeks.

The first year is the most stressful. After more experience it’s easier to be chill.

This is a really good time to get outside often and take time to observe the changes each tree makes in one’s collection. Also to research each type of tree in the collection. Goal to gets the basic horticultural needs down for each tree, as well as basic bonsai maintenance and techniques for each tree. The more time spent on the front end hitting the books, the sooner one has pre bonsai that can be worked.

cheers
DSD sends

 

[Bonsai Nut]

It's been a few weeks without water.

Also, depending where you live, a cheap trick is to put snow / snowballs / icecubes on your soil. When it gets above freezing, the soil gets automatically watered

 

[WNC Bonsai]

Also, depending where you live, a cheap trick is to put snow / snowballs / icecubes on your soil. When it gets above freezing, the soil gets automatically watered

Bet it works great in Charlotte

 

[Bonsai Nut]

Bet it works great in Charlotte

Well... we haven't gotten any snow this year or last. But two years ago we had one snow storm that lasted one whole day! Tomorrow it is forecast to be 64F

 

[rockm]

Ok, so if low 40s in the day and high 20s at high for 1-2 weeks, the trees can be watered safely? They are mulched, and most of the roots in the ground.

It's been a few weeks without water.

If they're under mulch, they're probably OK. Worth digging down to the root crown in a spot or two to see if there's still moisture there. I'd bet there is. I don't have to water my trees all winter once they're under mulch--rain and snow provide the water and it soaks down into the pile. The mulch captures and retains water at the surface and underneath and slows evaporation. If it's dry or dry-ish, turn a hose on it for a few minutes.