Cold Frame w/Heat cables

I would like your opinions if possible. I live in zone 5, in Michigan. I am in the process of building a cold frame for winter storage of my trees. Deciduous, Conifers and a few Carolinian cold tolerant trees. I plan on digging it 24" below soil level. It will continue to a height of about 16" above gound with a polycarbonate commercial cold frame as cover. The perineter below soil level will be 2x12"'s with styrofoam insulation covering the 2x12's. It will be 12" or so from the north side of my home. [color=red]I am considering placing heat cables on a thermostat kept at about 32 degrees Farenheit. The cables would cover the floor at several inch intervals. My question is DO YOU THINK THE HEAT CABLES ARE OVERKILL AND NOT NEEDED or would be detrimental. My thinking is the rootballs in the pots would never get bellow 32 degrees with the heat cables. I can set the thermostat at any temp from 0 to 100.

Hi Tom

In the basement with open windows, where I keep my trees. Do I know, if the temperature is ower freezing, will the tree look like sleeping, but the roots slowly grow.
I normally have between 2 - 4 degrees. If you can keep the airtemperature low too, is it the best.
Place the shelter in the shadow, no sun.

Kind regards Yvonne

There will be no sun exposure. I know the temps in the cold frame will be cold, very close or below freezing at times. My thought is the heat cable would keep the roots at 32 degrees (freezing) but would keep the temps and roots from dropping below that. I know the cold frame is the way to go but are the heat cables at the roots a good idea. I was hoping Tony may see my post and give me his thoughts as he uses heat cable to warm yamidori roots.

Thanks for our thoughts
Tom

Tom,
For many years in Pa. my shade house became my cold house in winter. The bows were from a 15' poly house. I allowed the trees to get some frost to go into dormancy then put the translucent plastic on, sealed the ends (except for a small door which fit nice and tight). Where I lived we could spend weeks below zero.

There was never a problem with a tree and, most of the time, there was a decent amount of humidity in there. When it seemed to get too dry I'd just throw some snow in on the floor (which was limestone).

Bob

Thanks Bob!!!

I have never tried this buy one of my friend here in central Indiana, have been storing his domant trees in the garage without sunlight for years. He said it's usually around 40F in the winter. He knows someone even put bonsai trees in a carbon box for the whole winter w/o any problem.

Well, I am from China and most people in China believe that even in winter when a tree is domant, it still needs some sun light and fresh air. I am going to try to keep a few of my hardy trees in the garage this winter and see how it goes.

Almost forgot: watering is a must even in winter! Just make sure you keep the medium moist, not too wet and you should be fine. Even in domant, the roots still grow slowly so don't let it dry out.

You want to keep the root ball of most trees in pots above 20F, they can freeze mind you its ok if the medium freezes but at 20F and below we can begin to get root damage. Some trees even though deciduous need even MORE protection and shouldn't dip below 30F. If your cold frame is going to have sunlight getting into it be VERY careful of it heating up. It can get surprisingly warm in a cold frame on a sunny winters day. One trick I've read and maybe this would work for you is bury it in snow, just a few inches this insulates and cuts down on hot sun in the frame. BUT every grower has to figure out where and how their trees store best, I think its all part of the learning curve. It would be helpful if you gave us a run down on what species are going into your frame.

Bill V. obviously keeps his in his garage over winter but I'm not sure if he has any sort of thermostatically controlled heat in there. He certainly doesn't have air conditioning in it

I've stored my trees in the garage for several years with a few losses, (not many). The problem I found with storing them in my garage was the door was opening and closing all the time, drastically changing the temperature, which is definately no good. Another problem if you keep the car in the garage the noxious fumes and salt from the car. That is why I am constructing the cold frame. I know a cold frame will work. I have a number of friends that use them. I like to complicate things and add. So my thought was I would place heat cables on a thermostat in the sand or gravel. I then could keep the temps on the roots from dropping below 30 degrees. The trees would go dormant but the roots would not freeze. I have a couple trees on the edge of hardiness for my zone 5. The heat cables would act as insurance more than anything. I thank you for your replies and advise....

Tom

drgonzo wrote:
Bill V. obviously keeps his in his garage over winter but I'm not sure if he has any sort of thermostatically controlled heat in there. He certainly doesn't have air conditioning in it

Bill Valavanis, International Bonsai Arboretum, keeps a salamander (a heating device) in the garage, and tries to keep the temperature at 28 F, about -2 C.
I try to keep my sunporch above 25 F in winter, but even with window blinds, when the sun comes out in February & March, it can shoot up to 50 & I run around frantically opening the windows. I have had a few losses, mainly trees that were overwatered in the fall.
Iris

A Salamander, I'm gone look that up!