NE Ontario in Ground market Greenhouse

Has anyone experience in using dug below frostline greenhouse dugouts in northern Ontario, ie Timmins area or equivalent, for more or less passive heating to supplement solar gain?

Don't have greenhouse experience. I was in Timmins many decades ago. It was late June and snowing in the afternoon.
I just wanted to suggest that you keep your mind open to the possibility of using spring water to keep the greenhouse warmer. Spring water at 55° is warmer than even that day in June that I just spoke of. On the other hand that same water would be welcome on a day like I saw near White River when it was 103° for 3 days in early June.

Solar gain is tremendously powerful.  The earth temp 4' underground in your area is likely under 45F.  Mine, way down south here in Wisconsin, is around 45 so I'm assuming yours is lower.  Glazing (poly or twinwall or glass) is amazingly poor at holding heat in.  So those are some variables for you to consider.  Also, in the winter, the low sun angle means a dug in greenhouse may have a significant shadow on the ground from the south wall.  Unless you dig it into a south facing hill which would be great.

We were going to try this on our property when we first moved here, but after we dug about 1.5 feet down, we quickly found out that our water table is too high.  You will find a lot of information about this type of design if you Google or YouTube the word "Walipini".  

I ran some math awhile ago for something like that in Sioux Lookout. At the equinox, a 5ft wall casts about 7 feet of shadow at noon.

You'll probably want a wall a foot or two high above grade and your frost depth is about 6ft.

Anyway my point is that it needs to be very wide in the south-north direction.

Nick Kitchener wrote:I ran some math awhile ago for something like that in Sioux Lookout. At the equinox, a 5ft wall casts about 7 feet of shadow at noon.

Wow, I wonder how bad it was at the winter solstice?

i plan on building something similar just up the road from you

i figure it will take many techniques combined to make it work

from what i have been reading it is better to build up than to dig in
set up drainage and then start mounding earth
jean pain compost heating
earth bermed south facing but also built up enough that snow could pile up 10 feet without blocking the light from coming in
vaccum insulated tank with hot water pumped in all summer
rocket mass greenhouse heater
and there are more
brain is not working at the moment so i will type more later

also at first i thought of a steep pitch south facing
which i will encorporate
but by the time it gets warm enough to bring plants outside.. the sun is very high in the sky and some plant may want to stay in there full time
either way all years worth of sun angles need consideration
i thought of something like teepees on top of the berm which have many layers of poly (mine is vynil) such that they insulate well
i plan on building mine upslope from a pond and on the north side so i will not have to cut down trees to keep the sun from being blocked over time although a marsh would work as well
i also thought of using roll up motors which roll up and down insulation once the sun goes down
a bc company sells the roll up controllers which are either on a timer or temperature dependant
more too... research first build later

Mike Haasl wrote:

Nick Kitchener wrote:I ran some math awhile ago for something like that in Sioux Lookout. At the equinox, a 5ft wall casts about 7 feet of shadow at noon.

Wow, I wonder how bad it was at the winter solstice?

About 16ft

An option is to align the pit greenhouse East/West and install a fish trough along the south facing wall since it will pretty much always be in shadow. Next to the fish trough, place the access path, and then the grow beds. Let's say, a 5ft wide fish trough, and a 4 ft wide path gets you out into the sun during periods of the year when you might actually be able to grow something. This far north, the winter daylight hours are short, and the energy density delivered during those daylight hours is low so realistically you'll be able to grow something (assuming it's above freezing in the greenhouse) from the beginning of March to the end of October.

It might not seem like much, but outside the growing season is probably middle of June to the end of September.

Now, with a long trough running along the shaded length of the greenhouse, you can put cold hardy fish species that like flowing water such as trout, grayling, or even sturgeon.

How big a green house are you thinking of. You say it's a market greenhouse so I assume it's not 8x10'.

I would consider putting in a source of some serious heat, like a wood stove with fans to move the air, prevent overheating one end. Another idea is one that was used here where it's much warmer. Fellow spent the year going from garage to garage collecting used motor oil. Could also use used fryer oil. He then used that in an oil furnace in his greenhouses.

John Indaburgh wrote:How big a green house are you thinking of. You say it's a market greenhouse so I assume it's not 8x10'.

I would consider putting in a source of some serious heat, like a wood stove with fans to move the air, prevent overheating one end. Another idea is one that was used here where it's much warmer. Fellow spent the year going from garage to garage collecting used motor oil. Could also use used fryer oil. He then used that in an oil furnace in his greenhouses.

Thanks all responses so far.  I have about an acre of land cleared in behind my work shed.  The soil is not good, clay, and I would like to be a lot more self sufficient.  There are local CSA's I could help supply but unlike a high population area demand is not that high.  Thus am looking to keep costs low for a year round operation.  I have wanted to do aquaculture so like the idea of incorporating that and was already looking at a depth of 8' to get below the frost line.  Possibly insulating the walls with straw bales in winter that could be incorporated in compost each summer.  It's an idea I am just feeling out right now.

solar greenhouse design involves: deciding how warm the growing area needs to stay, as in always frost free? warmer, light frost ok maybe? then decide how much space you want to enclose. aggle glazing to catch the sun at the time of year you will be using space. Determine how much sunlight will enter your glazing, and determine if you have capacity to store excess heat in soil or rocks under soil. The figure out if you can insulate non glazed areas. a structure set into ground is preferred as the ground is a stabilizer of temperature. then look at heat gain vs heat loss at night and decide if you need back up heat, such as compost, wood stove or such

Would love to revive this post! I'm in Iroquois Falls, and I used to live in Englehart (down the end of the Tomstown Road). I go to Timmins every few weeks or so. I am planning to build a greenhouse next summer, and will make a hoop greenhouse this year with just some 6 mm house plastic over some poly pipe with elbows at the top to make a gothic arch shape. I'm getting a truckload of topsoil next week and going to build the garden up because the water table is so high. I'm quite fascinated with the geodesic greenhouses here Arctic Domes but I don't have enough money for the size I want quite yet. The price of food keeps going up, and I feel an unquenchable urge to get food production going. I have started digging a well by hand, and I'm down about 8' in the thick, gummy clay, but now my hole is full of water. Literally. Like 4" of space left and the water will spill all over the grass, like flooding from below. At least I know I can dig a shallow well wherever I need water. My plan initially for the well was to get well tiles in place, maybe 15' down (was going to get an excavator to do that), and then have a cold storage/root cellar area around the outside of the well tile, to a depth of about 6-8', with earthbag walls built up to the height where I would need to protect from water, and then a cobwood pump house above ground with ridiculously thick walls and a nice south window, to keep a hand pump going smoothly.  The extreme height of the water table took me by surprise though, and now I'm considering making it into a small swimming hole/water source for fish pond and hydroponic system that is incorporated into the greenhouse as a heat sink. I don't have hydro to the property but we have a good little generator and I bought a shallow well pump which will need some work to get going, as it is designed to be wired into a house. So with a little work I can pump out my hole, and make it bigger, if I decide to make it into a pond instead of a well. I want to finish making the design plans for these projects and get a pump house done this year, so at least I can have running water over the winter, even if I don't manage to finish a greenhouse over a pond this year.  I would think a greenhouse that is to stay warm through Jan/Feb in our temps would need something like a pond in it to store enough heat. And would need more than just cheap plastic over top, and would probably need a rocket stove too. -40 is powerful cold!

How would you keep the water flowing? I like the idea of keeping fish in flowing water.