Growing Fruit Tree's in Containers up North

Hello Permies first time poster here

I live in southern maine on the boarder of what is known as 5a and 4b hardiness zone. Our soil is complete crap and not the good kind.... It literally is 100% clay about 1' down planting anything directly into the ground is totally out of the question. All of our gardens are raised beds ever since the first attempt at conditioning the soil which ended in a sloppy goo mess =/. Anyways I've been toying with the idea of growing a dwarf variety of self pollinating apple tree or a two varieties grafted together in a whiskey barrel. The problem being it would die over winter from the roots freezing solid. With some research I've found some people over winter their tree's in "unheated garages" we do not have one of these but we do have a detached shed with a wooden floor and not vary well insulated ceiling/walls. Although it doesn't seem to be any warmer in there in winter than the outside temperature. So I brainstormed a workaround here are the results. The plan is to build a box inside the shed out of some Styrofoam insulation sheeting, adding a common light bulb (incandescent for heat), and jimmy rigging it to a temperature controlled on off switch set to 35 degree to keep the trees dormant.

If the above does indeed work it should for any "container" fruit/tree/flower/ect serving a duel purpose of further dwarfing/training and the needed mobility factor for over wintering.

Does this sound even remotely viable option?

Welcome to the board

Any chance you have access to truckloads of wood-chips? If you can put down a heavy layer of organics over that clay it should (based on my reading) help to improve the soil over time. The ideal in permaculture is to design so you can reduce work and inputs. Building your semi-heated shed sounds like it might work but it will require your time and continual inputs. If you can get an organic layer started, and plant clay busting plants then you're addressing the root of the problem.

If "the problem is the solution" and you have a lot of heavy clay soil then use the clay to your advantage- make clay bricks, dig out ponds and grow fish or aquatic plants.

Food for thought...

The place where I live was first a alava field, then a mile thick glacier, then a waterfall river bed and later the river changed, and it became normal tundra, without trees, just moss, some birch and blueberries. For the last 20 years, poplar trees were planted and gave origin to a humus layer, where flowers grow. However the soil is still poor.

There is a lot of clay. However the addition of kitchen compost and more tree leaves and other plant material from the spot itself, makes soil much more fertile to grow vegetables.

However it still freezes hard solid for many repeated times in winter. Most apple trees can grow in sheltered spots, if planted when they are a few years old, and mulched with heavy layer of organic matter (which naturally forms by leaf fall in autumn). Pure clay will be more damaging as it retains much more frozen water. But if you add plenty organic matter, then the freezing is not as deep and as long-lasting.


Certain varieties are able to stand the spring frosts and can yield some fruit. People grow them near the Icelandic coast. Here further inland, we are just starting to experiment with this. Each winter is different.

Ed Johnson wrote:Welcome to the board

Any chance you have access to truckloads of wood-chips? If you can put down a heavy layer of organics over that clay it should (based on my reading) help to improve the soil over time. The ideal in permaculture is to design so you can reduce work and inputs. Building your semi-heated shed sounds like it might work but it will require your time and continual inputs. If you can get an organic layer started, and plant clay busting plants then you're addressing the root of the problem.

If "the problem is the solution" and you have a lot of heavy clay soil then use the clay to your advantage- make clay bricks, dig out ponds and grow fish or aquatic plants.

Food for thought...

Paulo Bessa wrote:The place where I live was first a alava field, then a mile thick glacier, then a waterfall river bed and later the river changed, and it became normal tundra, without trees, just moss, some birch and blueberries. For the last 20 years, poplar trees were planted and gave origin to a humus layer, where flowers grow. However the soil is still poor.

There is a lot of clay. However the addition of kitchen compost and more tree leaves and other plant material from the spot itself, makes soil much more fertile to grow vegetables.

However it still freezes hard solid for many repeated times in winter. Most apple trees can grow in sheltered spots, if planted when they are a few years old, and mulched with heavy layer of organic matter (which naturally forms by leaf fall in autumn). Pure clay will be more damaging as it retains much more frozen water. But if you add plenty organic matter, then the freezing is not as deep and as long-lasting.


Certain varieties are able to stand the spring frosts and can yield some fruit. People grow them near the Icelandic coast. Here further inland, we are just starting to experiment with this. Each winter is different.

Ed Johnson wrote:Welcome to the board

Any chance you have access to truckloads of wood-chips? If you can put down a heavy layer of organics over that clay it should (based on my reading) help to improve the soil over time. The ideal in permaculture is to design so you can reduce work and inputs. Building your semi-heated shed sounds like it might work but it will require your time and continual inputs. If you can get an organic layer started, and plant clay busting plants then you're addressing the root of the problem.

If "the problem is the solution" and you have a lot of heavy clay soil then use the clay to your advantage- make clay bricks, dig out ponds and grow fish or aquatic plants.

Food for thought...

Both of you kind of missed the point that I want to plant in containers.

Yes I forgot to refer the containers.

Freezing is way way easier in containers. Its really nasty for plants sentitive to root freezing.

Unless you have a species that is really "root" hardy, you must overwinter the plants, in an unheated space, protected from freezing but with enough light.

The shed you suggested, how much cold does it gets inside? If it just hangs around freezing, then it should be enough to prevent large damage to the plant roots, especially if the containers would be large and well mulched. But if it freezes the ground in there, then I would not put the containers in there. ALso assure there is some light, as darkness would not be good for the plants, because they would still be alive.

At least they are protected from frosts, wind storms and snow. That is already a big advantage.

It will be perhaps tricky to control humidity. You don´t want the soil to dry completely, but watering should be avoided when weather is near freezing.

Well, I feel like you, I also have tree seedlings in here and I don´t know exactly what to do. I will keep some outdoors, some in a unheated sheltered shed, and some indoors. Overwinter is always a challenge. Ensure you have a large and good balanced soil in those containers.

I am experimenting with growing various types of fruit trees in containers. My trees are tropical/subtropical types: Citrus, banana, pitanga (Surinam cherry), olive,etc.
These all overwinter fine in unheated parts of my house.


I think you have a good chance of keeping apples alive in a shed with the methods you described. One comment I have is that heat rises- an incandescent bulb might generate enough heat, but it may float up to the top of the box and not keep the roots from freezing.
Maybe a small fan to circulate heat? or maybe use root heating cables or a mini-radiant heated floor so that heat will rise through the pot.

Cris Bessette wrote: I am experimenting with growing various types of fruit trees in containers. My trees are tropical/subtropical types: Citrus, banana, pitanga (Surinam cherry), olive,etc.
These all overwinter fine in unheated parts of my house.


I think you have a good chance of keeping apples alive in a shed with the methods you described. One comment I have is that heat rises- an incandescent bulb might generate enough heat, but it may float up to the top of the box and not keep the roots from freezing.
Maybe a small fan to circulate heat? or maybe use root heating cables or a mini-radiant heated floor so that heat will rise through the pot.

Hmm hadn't thought of that (heat rising) it probably wouldn't be much of an issues as long as the thermostat on/off switch was at the root zone level. Correct? The box wouldn't be to extremely huge anyways 4x5 foot max just enough space for one small apple tree and a few dormant bonsai projects.

Hi Chris,

Can you let us know what temperature and how much light and watering do you provide to the trees? And how tall are those trees?

Cris Bessette wrote: I am experimenting with growing various types of fruit trees in containers. My trees are tropical/subtropical types: Citrus, banana, pitanga (Surinam cherry), olive,etc. These all overwinter fine in unheated parts of my house.

I am overwintering now seedlings (few months old) that sprout this summer of many different tree species, mostly fruit trees. The list of my seeldings is: tropical species: pomegranate, moringa, avocado, coffee; subtropical species: lemon, honey locust, lemon eucalyptus, chilean mesquite; temperare species: wax myrtle, almond, mulberries (morus nigra), siberian pea, silverberry, sea buckthorn, and apples.

The more tropical species like moringa, lemon or pomegranate are always indoors, at 18°C (64°F), watering only when necessary, sadly with zero hours of direct sunlight but several artificial fluorescent lights every night. I hope they can survive our dark winter. While the temperate trees can be cooled down almost to just above freezing, I can´t do that for the tropical species.

The more temperate species like apples, almond, mulberries I am moving them now to a plastic greenhouse at a controlled 10°C (50°F) but no artificial lights. Sounds a good choice no?

I wonder if I should try to move them to a open shed which is usually just above freezing temperature; but there the risk of freezing is much larger.

"Hmm hadn't thought of that (heat rising) it probably wouldn't be much of an issues as long as the thermostat on/off switch was at the root zone level. Correct? The box wouldn't be to extremely huge anyways 4x5 foot max just enough space for one small apple tree and a few dormant bonsai projects. "

Yeah, as long as the thermostat was a at root zone level, I imagine it should be ok.

Not got experience of this, but did have a very successful experiment with home brewing and a box made of Insulation Foam.

Had a garage where the brew stopped in winter so I built a box using insulation board about 80mm thick. It cut with a plaster board saw and took about 20 minutes to make. I had a small heater with thermostat inside and it used hardly any power to maintain a decent temperature inside. I know that ventilation and light weren't an issue for this, but heating a very small space worked very well. A heated brewing pad under the containers + a small light source might work quite well.

Dave Quinn wrote:Not got experience of this, but did have a very successful experiment with home brewing and a box made of Insulation Foam.

Had a garage where the brew stopped in winter so I built a box using insulation board about 80mm thick. It cut with a plaster board saw and took about 20 minutes to make. I had a small heater with thermostat inside and it used hardly any power to maintain a decent temperature inside. I know that ventilation and light weren't an issue for this, but heating a very small space worked very well. A heated brewing pad under the containers + a small light source might work quite well.

Thanks Dave! This is just the kind of feedback I was hoping for. Now that I know someone has done it or something similar it shouldn't be any issues over wintering small trees. Also considering building and heating a 10x12 greenhouse all year but that would be a lot more pricey to heat over the winter.
BTW how does homebrew stack up to commercial beer? I've done a bit of research on it (watched youtube videos craigtube) just haven't took the first step of buying a brewery.

When I bred reptiles I used to use a aquarium heater in a jar of water (pick your size) to keep the temps solid for the eggs. The plus is that that there's more thermal mass, the thermostat is built in, and they're pretty inexpensive

I like homemade beer and cider, but mainly brew wine. I do some using fruit and veg, but tend to cheat by using kits for most of it. 35 bottles of wine that tastes great ready to drink in 7 days. I used to make it in 5 litre demijohns, but by the time it was ready I'd drink it all. I still use the small demi-johns for home made recipes, but I do the commercial kits in 35 litre plastic drums. I've had people wanting to buy my wine, but usually end up giving it away. My missus didn't like the mess in the house so I moved it to garage, but it just stopped in winter. My 'brewbox' sorted it.. If I was doing it for plants, I think I'd use some of that double layered clear plastic sheets (they're like square cellular construction) for the sun facing side or a hydroponics light which would also help with the heating.

Hello John

I live in Australia, and although snow is not a common thing for us, frost can be. Insulation is the key to your situation, and keeping up the light. Suggestion would a clear piece of roof sheeting assist in the light.

I would look into finding out what are viable temps of soils that the fruit trees can you are interested in can survive. University and college website might have that information. By getting the approx temp they can survive in. will guide you with what temp you need to keep your pots in.

Insulation box, I have seen a couple made that have been used successfully to insulate pots. they have been built with compartments in the box to form different layers. Around the pots, straw was packed loosely them, than the next layer was dirt, the box was kept up off the ground also.

I would also look at any variety of any fruit trees neighbors or that have, to give you a clues or what can survive. Remember the trees are dormant during this time also. I have two ballerina apple trees in pots, and I get around 30 days of frost, they are doing great.

One thing, I have seen a banana tree grown in Tasmania and survive to bear fruit...so all is possible.