Frost heave of soil in winter

[canoeguide]

In a cold winter climate, Is it a normal thing to have a lot of frost heave of the soil in your bonsai pots? Mine seem to do so pretty dramatically. I have some 3" deep pots that are heaved as much as an inch - that is, the frozen soil is now 1" above the rim of the pot. This can't be great for roots that are tied down, can it?

 

[sorce]

Better fluffing than stuffing.

Sorce

 

[TomB]

In a cold winter climate, Is it a normal thing to have a lot of frost heave of the soil in your bonsai pots? Mine seem to do so pretty dramatically. I have some 3" deep pots that are heaved as much as an inch - that is, the frozen soil is now 1" above the rim of the pot. This can't be great for roots that are tied down, can it?

I see this regularly and have never seen any harmful effects from it.

 

[Wires_Guy_wires]

I've had it happen too almost every year. Apart from some soil falling out of the pots when the upper parts started to defrost before the rest, there haven't been any issues.

 

[leatherback]

yup. Water in the substrate expands and pushes out.
Keep the pots out of the rain and the substrate fairly dry to reduce the effect.