Mike's passive solar greenhouse design/build

Any new updates on this Mike?

Hmm, not sure.  The current status is that I'm considering the main interior space to be a "Georgia" growing space.  I haven't measured that area getting below 9F.  I currently start seedlings in there and have two peaches, four pawpaws, two grapes, two figs and an olive tree in that area.  Lots of peach flowers this year but it got too hot in the early spring and I think that cooked them and I didn't get any fruit.  Some grapes and I got a fig last year.

The area that was the compost bin now supports a yoga/sunbathing platform and under there I enclose it in the winter and heat it with a milk house heater.  In there I have a Calamodin orange, mandarin, two lemons, a key lime and an Australian finger lime growing.  

The greenhouse plastic is due for replacement some year now and I'm debating upgrading it with Solex or something like that.  If I do that, I'd consider putting some glass near the yoga platform for better tanning.  I'd also redo the lower vents since I only need one vent, not a full width row of vents (and thus air leaks).

I'm taking applications for "greenhouse fairy".  If anyone wants to play in the greenhouse, grow lots of stuff and make it pretty, it's available :)

Hi, Mike! We were just reading this thread and are wondering how your greenhouse turned out. We are thinking of doing something similar and we especially like the idea of heating with compost. We are in Michigan, zone 5b. Thank you!

I'd say that in zone 5b it would do much better, especially if you get a bit more sun than me in December.  My minimum temp measured so far is +9F and I'm in zone 4a.

The compost didn't work for me and I don't know how to do it inside a greenhouse and not make it smelly/funky/moldy/questionable for human lungs.

As an additional update, it's probably time to change out the plastic film on my greenhouse.  I'm considering different materials, perhaps fancy ones like polycarbonate or Solexx.  Solexx seems interesting but it seems like it's on backorder for about a year.  I'll look at polycarbonate next.  My rafter spacing is 4' on center and the pieces would ideally be around 18' long if memory serves...

I've heard from several people about using different coverings (greenhouse plastic, multicell acrylic, etc.).  One guy (I forget which video he produced) designed a greenhouse for the fancy multicell acrylic, and ended up putting on some regular greenhouse plastic just to get going.  It worked well, and then he did a cost benefit analysis and found that the nice stuff cost 30x to 50x, and was only expected to last 10x as long.  Most people I know just use a good quality UV resistant heavy greenhouse plastic, and it lasts them for years at a time.

Hope this helps.

Thanks Ebo, I was surprised that Solexx only had a 10 year warrantee compared to 4 for plastic film.

Hi Mike;
We have had solexx on our greenhouse for apx 13 years now.
It shows its age but is still doing its job.
We bought the rolled solexx,  4'1.5" wide, 100' roll shipped free.
The hard panels were scary truck freight shipping and had to be ordered.

I have not looked closely at Solexx, and it might well be worth the extra cost.  I just remember pricing the double wall ridged panels for a 48' greenhouse at something like $14,000, and a high quality greenhouse plastic that could be expected to last 4 to 6 years was $300 or so.  The ROI between the two products were a no-brainer, although you do have to account for the downtime while you are replacing the covering...

BTW, remember that the *warranty* is typically 1/2 to 3/4 of the life expectancy of a product.  The manufacturers do NOT want to have to pay for anything once the job is done, but the warranty will help them get jobs.  So there is a fine marketing line where it is cost-effective to set the warranty duration.  So, when looking at the products, you can often expect them to last 2x the length of time, but often in a degraded capacity.

BTW, Gorilla Glass was working on a greenhouse glass product several years ago.  I bet is it uber expensive, but likely have a life expectancy of 100 years...

thomas rubino wrote:Hi Mike;
We have had solexx on our greenhouse for apx 13 years now.
It shows its age but is still doing its job.
We bought the rolled solexx,  4'1.5" wide, 100' roll shipped free.
The hard panels were scary truck freight shipping and had to be ordered.

I could also see where property location latitude might impact this as well.  All of our implementation of passive solar has been vertical....no angled glazing for summer sun (northern hemisphere).  I suspect this may extend the life slightly due to the fact that the panel (5/8" twin-wall in our case) cells are supporting much of the panel weight plus they are not getting direct summer sunlight and daylength. And our panels were obtained used.....quite probably 8-10 years old at the time of acquisition and sporting several patched holes from hail damage.  So along with Thomas R. observations, with some care they may last quite a bit longer than the warrantee indicates even if the quantity and quality of light transmission suffers a bit with that aging.  Great to see all of the valuable info and experience detailed here for northern homestead greenhouse builds!