The fellow in Nebraska wrote an e-book about this some years back called “Citrus in the Snow” or something very similar.
A recent discussion on weather problems included a discussion of using controlled environments to protect against weather, disease, and pests at the same time, if properly designed. Some good ideas can be taken from the work these gentlemen have done.
It’s a great topic and I’m glad the story is getting out there. Thanks for posting about It! Oranges in cold locations could change everything. Citrus greening disease is getting bad in Florida so alternate locations are fantastic!
I’ve visited Bob Duncan in BC and yes, his citrus trees are absolutely incredible! We can grow sour citrus in the NW with just a bit of protection as we rarely get freezing temps.
Sweet Citrus is more difficult as there aren’t enough heat units here.
Although we are quite a ways south of the Duncans (almost in another country!), freezing isn’t rare around here. We are farther from the sea, so we get more cold and more heat, although less of either than most parts of the US. I knew a guy in my neighborhood who grew kumquats in a large container, and he only needed to wheel the container into a garage for about one week per year. We usually get down to 15-20 degrees Fahrenheit, and many, many days down to 25-30 or so. We can also grow limes, lemons, etc. that way.
I’m not sure it’s as expensive as you think. Where there is a will there is a way. I know some people have bought 120’ greenhouses on Craigslist for $600 but they had to dissamble it , clean up the mess, in some cases you might be required to plant grass where the greenhouse was. Pipe is very cheap but it takes a lot of time to work with used stuff. The opportunities are the hard part for me to recognize. There are guys selling used pipe for 50 cents a foot I just need to invision in my head at the time I see the supplies what it takes to put it all together. On those days you feel like doing nothing is when the phone rings with the best deals. I passed up a 150’ used green house myself for $200 once because the greenhouse dissambly was the easy part. I think it was on a concrete slab which needed removed. I just did not want to spend 5 hours with a bobcat pulling up a slab and digging holes to bury it. Honestly the bobcat would have cost me $400 and that’s a reasonable price. If I was more industrious I would have charged someone $700 to fill their ditch nearby and grabbed a friend with a truck.
Lots of people have wondered about the basics about how geothermal actually works which I’m going to try and break down in a simpler way. The soil maintains consistent temperature if you go down deep enough which is the premise behind heat pumps, geothermal greenhouses etc. That temperature depends on your location which is 45 °+ farenheit in northern states, and 50 °+ F in the southern states in the United States. So you might be wondering if your in Kansas how warm can we keep a greenhouse using geothermal heating and the answer is at least 20 °+ what the temperature is outside. You will need your pipes below the frost line which is 8+ feet down in some places but typically 4-6 ft is ok. You need to know cubic feet of your desired size greenhouse to know how much pipe your going to run. In my case if i wanted to install geothermal in my hoop house i would look at my dimensions
Width: 7 ft
Length: 25 ft
Height: 6 ft
LxWxH = roughly 1050 cubic ft
We here that calculation also called Cubic Feet of air volume per Minute (cfm). So now i need to make sure I have the right fan (1050 CFM rating) & geothermal system that will be needed for the greenhouse. The way it works is we recycle air in the greenhouse through the ground which is warmer or cooler depending on the time of the year. The greenhouse will run hotter in my location if I have the long side facing South to catch more of the sun just like solar panels. If I use geothermal I don’t vent the heat out the window but rather cycle the heat with a fan through the ground. If i warm the ground and it’s insulated the heat is there stored in the ground later at night as things cool down. Many traditional greenhouse growers accomplish a similar result by painting water barrels black and warming water with the sun so the temperature is warmer at night. The more pipes underground and the bigger the circumference the larger area they can heat. Digging up a huge area and installing pipe is beyond the scope of what many of us need in which case we stay with a traditional method.
We know this gentleman in alliance Nebraska has done this for 20+ years. Tours are available to see his greenhouse in person. As i mentioned at the top of the thread this is what he does and how he does it.
That is super interesting. I was considering to use the solarpower which is left over when the sun shines to use it to boiling water for heating a greenhouse or even to use for the house.
I mean it get wasted anyway, if you haven’t an expensive battery to save it.
I went on holiday in iceland and visited one of the tomato greenhouses. Because of the volcanic activity, heat and electricity is almost free.
they could grow anything.
I asked why only tomatoes. The answer tomato’s bring more money
The model of the „earth greenhouse“ or walipini or whatever it is called is very interesting.
super practical and very effective passive use of „geothermal“ energy, without pipes or pumps and electricity