A Winter Greenhouse Construction Plan for Northerners

[Aquamaple]

First off, happy 2014 fellow aquapons! I am building a winter-ready greenhouse this spring, currently building a materials/cost list which led me to some questions you all may have valuable experience with. I hope this thread will be invaluable to others such as I who wish to grow year round in cold climates. It is currently January 2, 2014, and it has been below 20°F for a couple weeks now with air temperatures monday expected dropping to 5°F, possibly below 0°F for the rest of the week. I need serious thought to go into this greenhouse, and I have thus far researched much and pondered greatly on the topic. If I remember correctly, I live along the 42nd parallel, in Michigan.
Please excuse the jumbled communication, I'm using my phone and apparently it doesn't like the mobile interface because I can't scroll up to edit my text. I will add to this thread and edit at home, when possible.
I have found successful designs I plan to base my greenhouse off, and I will soon link those so you may have an idea where I am headed. Essentially, it will be tall and insulated on the North side, a steep glazed roof sloping toward the South with a shorter wall there. I will explain more of my ideas later, but that is the gist of it. I plan on using a combination of SHC and geothermal energy.
My first questions:
1. I am capable of building, but not too knowledgeable about building trades, as of yet. WHAT would be the benefit of using a concrete perimeter foundation as opposed to just planting my treated posts in the dirt? I plan on using foam board underground all the way around to assist with insulation. Im sure a concrete foundation would look prety and work well, but I currently see it as an unnecessary cost. Am I right? The inside square footage of my GH will be dirt, for many reasons I will later explain.

Thanks for all your help, this is going to be a fun project!

[Jeremiah Robinson]

Sonja your greenhouse is awesome!  Is there anyplace that your design and pictures are posted online showing the story?

Sonja Martin Young said:

We just finished our 22x 36 greenhouse here in Homer, Alaska. Not quite as cold as you get but for longer. Probably similar frost line. We put 2 inch R tech on our cleared pad and then put Amvic blocks (that you normally fill with concrete) around the perimeter. We filled those with packed sand. We put hot water piping on the R Tech and air pipes ( for a climate battery). Then we put 18 inches of packed sand on top. We laid timbers on the Amvic and built the greenhouse on top of that. Then we put R tech 2 feet laterally around the outside to keep the frost from heaving the foundation. Oh yes it is expensive but I hope to only do it once and do it right.

[Sonja Martin Young]

Jeremiah, thanks, I think it is awesome too. Did you see my Alaska Aquaponics video? I am ready to do another soon. I took a lot of photos of the building process but have been so busy building that I haven't posted the story yet. I just finished my 8x25 foot raft bed so maybe I will have time now.
Aquamaple, so far I am really happy with the insulation that I used. We did not hook up the water or air pipes yet so that will be a discussion for next winter. I plan to use an on demand water heater for the pex and will be able to add some to the raft bed or under the media beds. I hope to get the air pipes hooked up soon. I have not experienced any ground heave which was really important to me. I am eager to do more insulating next fall but right now I have to open it up each day to keep it cool. ( my next project is to get the shutters and external fans up)It holds heat way better than the double layer poly greenhouses that are prolific in this area.

[Jeremiah Robinson]

Hi Sonja,

Thanks for pointing me to the video.  It looks great in there!  

Also love your accent.  Are you from Wisconsin originally?

I was thinking of ways that you could put some more passive solar design features in there, but then I realized you probably don't get much winter sun do you?  That makes for a really interesting design challenge.

Your insulated fish tank looks awesome - great idea!

You probably could save some more energy through preventing evaporation from your grow beds by planting your plants in net pots through a 1" sheet of insulation laid over the top.  The roots would grow down into the media from there.  I did that this winter and it made a huge difference (see pic.)

[Jeremiah Robinson]

Sonja, I was thinking that it might be interesting to use your greenhouse as an example on my blog, to ask readers what features they see in your greenhouse that they think are great ideas, and what improvements they can imagine.  

Would you be open to that?

[Sonja Martin Young]

Sure, maybe I will get some good ideas for my next project. Did you need more photos? What specifically? Let me know.

[Jeremiah Robinson]

Hi Sonja,

If you had some photos of specific components that would be helpful.  I'm looking in particular for things that you think make a difference in saving energy.  

Good examples would be things that:

• insulate,
• air seal,
• hold heat,
• recycle heat,
• provide heat efficiently,
• prevent evaporation,
• reduce the need for heat,
• direct heat to the right locations,
• etc...  

Also anything that you think makes your system unique.  

If you wanted to explain it for us in text, that would be welcome too.  

Whatever effort you want to put in is fine.  I really appreciate whatever time you're willing to offer us.

There's also a new group here on the forum about cold weather aquaponics if you want to participate in that discussion

Thanks!

[Tammy Resseguie]

Aquamaple, I too live in Michigan and would love to hear more about your greenhouse plans. I would love nothing more than to be able to do aquaponics year around here but thinking it wouldn't be real cost effective. Have you started building yet??

Thanks,

Tammy

[Jeff S]

Hi Tammy, I live in a western Detroit suburb. Not to many aquaponics  enthusiasts around here. I've been at it for about a year. Getting ready to expand my GH. Looking for flooring recommendations.

[Jeremiah Robinson]

Is there a reason you want to put in a floor, rather than just leaving the dirt exposed?

[Jeff S]

Dirt gets muddy. I found that out this year. I laid some 18" tiles that I had on the ground to stay dry. Also I read somewhere that gravel will absorb heat during the day. Any kind of flooring should insulate from the ground to some extent.

[Aquamaple]

Tammy, no I haven't started building yet. My broken ankle from JANUARY is STILL broken so it looks like this will be a project for next year. I just consider it an opportunity for more research :-)

[Jeremiah Robinson]

That makes sense.  The best surface for absorbing heat is something with high mass, such as concrete.  A bit of insulation with black-tinted concrete poured on top of it would absorb a lot of heat.  In summer you'd need some way of reflecting that heat though, such as a layer of sand.