This is a followup note to my original posting http://www.websitetoolbox.com/tool/post/figs4funforum/vpost?id=2959163 regarding the growing of fresh figs for market in Missouri. I have not had time to process all of the information from the visit nor have I yet had time to research the topic in great depth. I will do my best to explain my observations from my short but impressive visit. (This is also posted on G.W.)
  The first of his two 30’x100’ greenhouses is filled with figs. It is heated with vegetable oil and is cooled by the raising of a curtain on both sides of the greenhouse (cross ventilation) with an electric motor that runs off of a battery that is charged by a solar panel. The motor drives a worm gear that pulls a cable and pulley system that raises the side curtains (both sides) of the greenhouse, allowing for cross ventilation.   It cools down adequately on hot days.
    His "solar geothermal" hoophouse contains about %25 figs and the rest are vegetables and strawberries. This house is cooled and heated by taking advantage of the thermal mass under the greenhouse - a subterranean heating and cooling system. The earth under the greenhouse was excavated to install two heat exchange systems - two is needed to maintain maximum efficiency. Each system is composed of 16 rows of 4" flexible perforated tubes, spaced 1 foot apart. The 4” pipes connect to a larger pipe (15”??). The two larger pipes connect to a 20” vertical pipe for input and output. (see my basic drawing "Photo 15 link)

     Air is blown down one 20” pipe and comes out the opposite corner.  During the day the fans run, pushing the the warm and humid air through the pipes.   Mold, fungus, and mildew does not form in the tubes because it is an aerobic system. The nearly continuous air flow plus the perforated pipes contribute to the health of the system.  The perforated drainage pipe allows moisture and heat to transfer between the soil and the pipe.   This also warms up the soil which is good for the roots, especially when front and back end seasonal temperatures are cold.    (He planted some fig cuttings this spring and they are already making figs on their 5-6' stems! See the photo below)
  At nighttime the fans can run and the heat that was stored in the ground becomes available to warm the greenhouse. Warm moist air is produced by the system at night.
There is also a thermostatically controlled exhaust fan mounted on the back wall to pull out excessive heat during the day.  The fans that blow air through the underground grid are also controlled by a thermostat.     I am not sure of the exact temperature levels that are set for day and night time running cycles. (He has a goal to someday run these fans off of solar electricity if I remember correctly)
The coldest that it got last winter was about 2 below zero F.    The geothermal system kept the greenhouse around 43 deg during this coldest time.  That is what really impressed me!   It is like having a Mediterranean microclimate all year.
    The outside of the greenhouse has a thick blue styrofoam insulation skirt that extends about 2 feet outward on the ground level, then extends about 5 feet into the ground. This is more important in the winter time, keeping the frozen ground at some distance from the edge of the greenhouse.   He has a double layer of plastic that is inflated, especially in the winter months.  This adds some insulation value.
The minimum sized greenhouse that will will function this way is 1000 sq feet. Small houses end up with more exposed surface area relative to the amount of underground heat storage.
If you are serious about this type of greenhouse - shop around. There are huge differences in price with little difference in quality in some cases. Also, thoroughly research your plan. Fossil fuel heated greenhouses are wasteful and expensive to run - this alternative design really saves a lot of money and energy in the long term.
Here are some photo descriptions (probably are not in order of the uploads)
This first photo shows the dense fig tree growth in his first greenhouse.

The second photo shows the outside of the first greenhouse with the movable curtain to allow ventilation.

The third photo shows one of two exit vents from the underground system Clean dry fresh air!

The fourth photo show an input fan next to a bed of strawberries.

The fifth photo shows the first years growth from cuttings - now five to seven feet tall and ripening figs. The warm soil makes them grow fast.

The last photo shows the outside of the first greenhouse with the ventilation curtain open. There is a forest of Brunswicks growing outside.


A) Build it Solar - http://www.builditsolar.com/Projects/Sunspace/sunspaces.htm B) Permaculture Greenhouse - http://www.midwestpermaculture.com/GreenhouseDescription.php
C) Calculations - http://numsum.com/tag/show/greenhouse
D) SunnyJohn - interesting array of info - http://www.sunnyjohn.com/indexpages/shcs.htm
E) Columbia Tribune - another article about Ivan’s greenhouses - http://columbiatribune.com/2008/Sep/20080912Busi009.asp

By placing your curser over the photos below, the title will likely make an appearance.

Ingevald

Yes Ingevald, I've alot to digest also!
We went to a workshop with a local farmer to build a 100 x 16' x 7' high Hoop House. Pictures can be found here:
http://share.shutterfly.com/action/welcome?sid=1QZtWLRw3YsJ8

[sorry for no captions but check out #81 & 87 for an overview].

This is low cost (about $1300) & very do-it-yourself. We had 40 folks but we figure a team of 4 could do the whole thing in one day, with one day to prepare the materials (cutting rebar, bending square tubing, prepping the ropes.)
The beauty part is the ropes hold the plastic under tension such that it can be very easily lifted up for ventilation.
Like I have written before, I had no intention of being interested in greenhouses but this past summer has changed all that.
Now about that geothermal...
Thanks for a very informative post.
Stephen V.

Gotta bump this thread.  It's one of my all-time favorite threads here on F4F and it only has 1 reply!

Thanks for the great writeup, Ingevald.  As you know, I also make extensive use of geothermal climate control, and I enjoy reading about folks who think along similar lines.

I don't know where you are in Kansas but Byron is a great man. Maybe you should try getting a hold of him. He shouldn't be too far from you.

I'm near Manhattan.  We've emailed back and forth several times, I like him.  We've got a lot in common.

I know he's involved with the community garden/orchard in Lawrence, and one of these days I'd like to be able to go help set up a nice aquaponics system for them (and for a lot of other community gardens around the state), perhaps even a passive geothermal banana/fig tunnel.  Maybe next spring?

But I'd also like to set up the largest greenhouse/covered fig operation in the country here in my hometown and invite everyone from F4F for an annual taste-testing shindig, so first things first :)  I figure we've got great meetings/operations going on in the South and on each coast, so we need something big here in the middle.

He is a good man.
Last time we communicated was about three or four months ago. One of the two remaining Ischia Black is for him.

I don't know where exactly Manhattan is but I sure miss riding along I-70 in the western part of the state. Closer towards Colorado.
Such beautiful greenery, I was at peace when I used to go through there.

"Fig Shindig" will be awesome

Time for a second resurrection :) I just ran across this. This is the same type of system that we use in our greenhouse. It has been quite impressive how it works. Also check out Central Rocky Mountain Permaculture Institute. They are the ones doing the most research into this type of system that I know of. They just came out with a book called The Forest Garden Greenhouse. That will really make you drool :) I loved the pictures above showing the greenhouse full of figs. That's my goal. Just need to get more figs......

Wow thank you Kyle for resurrecting this amazing info. With our nites in the 20's now in central AZ this is fascinating. I'm just imaging a saltwater therapy pool in the middle of figs, bananas and citrus snuggled under the greenhouse. Right now I'm listening to the wind coming off the ocean in Cabo San Lucas Mexico. Warm sun, warm breezes and green plants! As yet no figs in sight.

Thanks for the resurrection of this posting and the concept.   I am very appreciative of the mentioning of the book "The Forest Garden Greenhouse."   I look forward to getting that resource sometime soon.   
 
Thanks!

Byron (Ingevald)

Hey Bryon. This is your original post? Any follow up info? Is it still operational? And I ordered the book too. Looks great. ;-)

I'm not Bryon but I looked it up today and it appears he is still operational. Good reviews on his figs. I'm sure you will love the book! We are one of the case studies in the book so you can check that out if you want. The pictures are from when we had just finished it up so not a lot planted in it yet in the pictures in the book.

Hello - Yes, this was my original posting.   I've been sidetracked due to other happenings in life (elder parent care being the current issue).  I occasionally collect research materials and think about this concept.   I've not written any papers on the topic other than what appeared on this posting and the original posting.   I think that the book that Kyle mentioned will be very informative.  

The original operation that I wrote about is likely still in operation near St. Louis.  I've not been in contact with him for a while but had a report a couple of summers ago that he was still selling figs at the market.

Remember that there are two variations of this "geothermal" heating system.   The book that has been mentioned may have other additional information.    Anyway, there is the system that Ivan uses near St. Louis that has been described in my postings.   I may have mentioned it in another posting, but Russ Finch in Alliance, NE has a similar system but it is different because it is pulling heat out of the ground continuously and not using daytime replenished heat like Ivan's system.   http://www.citrusinthesnow.com/    Both systems work.   Ivan's will leave your greenhouse less humid and Russ' system will be more humid. Anyway, the info is in the postings for further research.   

Thanks again for the followup postings.   If anyone has additional contributions (photos, new books, scientific papers, articles, etc) please post the information.

Take care,
Byron (Ingevald)