Warming wintering roots?

[Guns286]

I've said, in another post, that I've seen a video where a guy talks about using reptile heating cable to keep his Bonsai's roots from freezing. Is this is a necessity? I realize that different trees/plants require different things. I have 1 Willow cutting in a 1 gallon pot, 2 pre-Bonsai White Oaks, and 2 Apple tree cuttings. I plan on putting them all in a DIY greenhouse box for the winter. Will that be enough? Or do I need to put a heating cable/pad in the bottom as well? I live in New York, so the winter temps can get pretty low.

 

[Dav4]

I suspect all those trees are native and winter hardy in your area and should do fine frozen solid all winter long.

 

[0soyoung]

The reason, I think, is to keep the roots from getting too cold, not preventing freezing per se. Except for extreme alpine species, most temperate tree roots are okay as long as their temperature stays above roughly 20F (15F for most maples), regardless of robustness of the above-ground part of the tree to colder temps.

Commonly people in the U.S., Canada, and northern Europe accomplish this with just the insulation afforded by heaping mulch over pots placed on the ground.

 

[JudyB]

I use this technique (but with heat mats) to keep trees that are not hardy in my zone, and also to hedge my bets with protection. I keep the heat mats just around freezing on one side and higher on the other side for less hardy trees.

 

[Guns286]

Ok. So if I didn't use a heating pad or cable, wrapped the pot in burlap and covered the soil in wood chips do you think I could just leave them in my shed, with no sunlight? Of course I would water them every couple of weeks.

 

[Dav4]

Ok. So if I didn't use a heating pad or cable, wrapped the pot in burlap and covered the soil in wood chips do you think I could just leave them in my shed, with no sunlight? Of course I would water them every couple of weeks.

Yes. You'll need to take steps to prevent rodent damage, though...spring traps were my preferred route, and moth balls in cheese cloth have been used by others as a repellant.