Root-zone heating - Part One

[Carey Ma]

Root zone heating

I'm from Indiana and many years ago I went to collage in Berrien Springs and then Lansing so I know about the wind-chill factor and lake effect. You poor soul! My situation isn't much better; in fact other than the heavy smog (all year long) we have here, it's quite the same. Hot muggy summers and bitter, dry, cold winters.

 

The following holistic ideas can be used in a layering method to supplement enough heat to grow food even in extremely cold conditions.

There are several thing we can do but first I think is to insulate everything you can; top, bottom, sides (tip: if you want Styrofoam to last, try laminating it, (inside and out if possible) with UV resistant, shrink-wrap plastic or better yet use HD PE boards, which water cant penetrate (closed cells). Insulate, insulate, insulate!

With that said, I will introduce you to the concept of zone heating or more specifically, root zone heating. When I was doing Home Automation, I learned that almost everything was more efficient if broken down into layers like an onion (multi level), and zones, instead of just sections like an orange (multi zone). It is not necessary to heat large spaces such as home or greenhouses. Simply heat what needs heating to provide comfort. For example: I would run low voltage, in-floor electrical heat for immediate use like going to the restroom in the middle of the night. Or better yet incorporate one of those Japanese hi-tech toilets that includes heated seats and and low glare radiating heater for your body. Now that’s what I call efficient comfy. The air is still cold but the home user is comfortable the entire trip, at a fraction of the cost of heating the whole house. Try to break it down and heat small, insulated spaces, instead of large areas that aren’t really productive.

As I said earlier, there are many ways and places that can affect you propagation efforts. Root zone heating is one of my proudest discoveries (copyrighted and patent pending but I’ll go ahead and share with you to use in your operation).

For soil only gardening: One way is to use compost as has been mentioned earlier, but instead of piling it up on the outside of your greenhouse, might I suggest piling up inside the greenhouse, around the fish tank or the north side of the greenhouse.

Take a squirrel cage fan and fasten it to the top of the greenhouse. Then connect the appropriate duct material (like that used for dryers) and bring it to the floor level with two feet to spare. Now comes the fun part. Dig down and remove the topsoil of your beds and put it in one pile. Once the topsoil is removed, remove the remainder until you reach a foot to sixteen inches (six to twelve inches of rich organic soil, and four inches for the pallet). Once it is raked and even, take out half the boards and staple geotextile over the openings and place shipping pallets in the hole. Arrange it so they fit nicely in your bed. Now place the duct into the space between. Cover with dirt. Now you have a better use of the off gasses while getting almost free heat at the root zone. Solar thermal mass would also add to the efficiency, which brings me to heating the tanks.

Fish tank heating with solar: Although tunnels are wonderful for their function one can’t really beat the simplicity of Chinese greenhouses called “Da Pung”. In their case the back wall is made of brick and often piled with dirt on the outside acting like a giant heat sink. I would take away the dirt and line the wall up with cans painted black and store the hot water in an insulated in-ground cistern before going to the fish tank or grow beds in case it gets too hot. A regular solar water on the outside of a high tunnel would work just the same, (without wasting any grow space).

 

In wicking systems or raised beds; plastic pipes can be (run 4-8”) in the soil under where your plants will grow, (above the separation plate in wicking systems).

Another option is to use electricity although some sustainable purists think it is an option that supports the use of dino oil; I think efficiency coupled with need outrank their mandate. Here I would use low voltage (9V) resistive heating as used to deice water pipes, driveways or as in floor heating. I would place these in the soil as above. In the case of wicking systems I would run it through both the water and the soil.

Sharing the greenhouse with animals during the day can also add to the total heat plus give off CO2 for healthier plants. In our case I guess our livestock would be fish.  

 

 

 

 

 

 

 I would also add a cold sink in the inside, front (south) of the greenhouse to draw away cold air that sinks to floor level out of the grow area and lessen the amount of solar energy it would take to heat the floor.

Hmm..well I guess I’ve rambled on long enough. Please feel free to encourage part two of this article…haha

Anyway, get the roots comfortable and you'll be pleasantly surprised at how low ambient air temp can get before it really affects growth. Be creative & have fun.

 

Cheers

 

 

 

[Ellen Roelofs]

Wow! I need to file this away someplace safe... priceless!  I am with Owen in MI.

[Eric Warwick]

"I am sure it would do something to help but I think moving the water via insulated tubing would bring more heat to needed areas a bit better than through conduction alone and the whole idea is not to heat the greenhouse but only the root zone." Oh, that makes more sense.

[Carey Ma]

Hi Eric,

I am sure it would do something to help but I think moving the water via insulated tubing would bring more heat to needed areas a bit better than through conduction alone and the whole idea is not to heat the greenhouse but only the root zone.

[Eric Warwick]

Would a covered heat conducting material, such as copper, that runs through, or around a compost pile effectively heat a greenhouse or fish tank--the fish tank being a thermal mass.

[Carey Ma]

Thanks for the suggestion. That might be an option for daytime use but burning anything in a greenhouse is not conducive to human health and takes away oxygen desperately needed at night. Besides, corn cobs here are a commodity. They use it to start their coal fires with during winter. Dried corn leaves are used as TP in poorer households.

 

Similarly they use coal furnaces to heat their greenhouses, extending their metal chimneys pipes through the length of their greenhouses to provide heat. Off gasses go directly outside.

[Calvin Schmidt]

you could also experiment with a rocket mass furnace to heat a buried cob heat sink... You'd only have to burn for a couple hours a day to "recharge" the cob heat sink. Plus you get some CO2 out of that too.

[Carey Ma]

My pleasure David.

[David Owens]

Fantastic article Carey! I'm off to study cold sinks and redesign my winter plans. I hate even talking about the cold right now but a little planning could ensure that we are eating well and my Tilapia survive through the long, bleak winter. -Thanks!