Trees are lifting out of pots in winter storage!

[Kahless]

My trees are outside and covered in mulch in my garden. Last spring I made pots by drilling holes in plastic feed pans and oil drip pans. I just noticed that all the trees that are in plastic feed pans have started lifting out of the pans (from freezing soil I assume), and about an inch of soil is exposed. Are these trees going to be okay?? should I put more mulch on? I can't stop worrying about them. Losing trees absolutely kills me. I wish it would snow

this is an example of what I used.

 

[Dav4]

My trees are outside and covered in mulch in my garden. Last spring I made pots by drilling holes in plastic feed pans and oil drip pans. I just noticed that all the trees that are in plastic feed pans have started lifting out of the pans (from freezing soil I assume), and about an inch of soil is exposed. Are these trees going to be okay?? should I put more mulch on? I can't stop worrying about them. Losing trees absolutely kills me. I wish it would snow
View attachment 523797
this is an example of what I used.

There's nothing to do imo, assuming the pots can drain adequately, other than making sure there's adequate mulch on and around the pots. If there's any chance drainage is poor, possibly due to inadequate drain hole size or number, and/or the holes aren't draining do to where they're currently sitting, I'd want to fix that sooner then later.

 

[badatusernames]

An inch is a lot, but I've seen akadama lift out of the soil on my trees in cold weather before as well. I don't think any that had that occur died.

 

[Deep Sea Diver]

Frost heave is no stranger in our area, considering the amount of rain followed by hard freeze periods we have about 3-4 times a year. Haven’t ever affected the bonsai mulched in.

Curious… including positive drainage, which would also be my first guess, are the trees mulched in on sides and top?

Cheers
DSD sends

 

[Kahless]

Frost heave is no stranger in our area, considering the amount of rain followed by hard freeze periods we have about 3-4 times a year. Haven’t ever affected the bonsai mulched in.

Curious… including positive drainage, which would also be my first guess, are the trees mulched in on sides and top?

Cheers
DSD sends

Yes, the sides and the top.

 

[rockm]

If the trees are heaving out of their pots, those pots aren't draining adequately. I'd go out and punch some holes to increase drainage, or elevate the bottom of the pots off direct contact with the ground, OR move them to place where they don't get as much precip. Slow draining pots can be a problem during overwintering. Slow drainage can means the roots are sitting in water.

It is important that before you mulch pots over you insure the bottom of the pot isn't sitting directly on the ground and they're as level as possible. I place my bonsai pots on bricks on the ground before mulching them over in the fall. That sets a gap between the pot drainage holes and the ground improving drainage. Setting the pots directly on the ground blocks drainage. That can be true even if the pot has feet, as those feet will sink into the ground over time with the same results for poor drainage.

 

[Wires_Guy_wires]

I have good drainage and sometimes it just happens that water expands from the soil particles, especially when the frost is really rapid.
We went from +5 C to -5C overnight and this time it didn't happen. But last year and the year before it was pretty common. When the thaw came, everything settled again and it was like nothing ever happened.

Plastic is a terrible insulator and I think that that property has more effect on your soil heaving out than the drainage.

 

[Deep Sea Diver]

I have good drainage and sometimes it just happens that water expands from the soil particles, especially when the frost is really rapid.
We went from +5 C to -5C overnight and this time it didn't happen. But last year and the year before it was pretty common. When the thaw came, everything settled again and it was like nothing ever happened.

Exactly what occurs in our area. Fast freezes and the ground heaves, especially in areas where soil/media is uncovered. Mostly in unshaded damp areas. But will do all over the area if the temperature drop is sudden, about 18F/10C changes seem right on the money.

A bit less of a temperature change often merely yields hoarfrost. If tule fog or the like is about rime ice forms.

Plastic is a terrible insulator and I think that that property has more effect on your soil heaving out than the drainage.

Yep. Felt like a drainage issue though, considering all other variables.

cheers
DSD sends