Earth-Heated Nebraska Greenhouse

Earth-Heated Nebraska Greenhouse BUILDINGS Miscellaneous Brian and Zoe Vakoc are looking forward to picking lemons and avocados in their earth-heated greenhouse They have already enjoyed mid-winter greens and sitting in the greenhouse when the weather is cold outside They are also looking forward to fresh fish from their aquaculture system Vakoc credits Russ Finch for the concept Finch developed a greenhouse design warmed by air drawn through in-ground flexible tubing Vol 37 No 2 “I visited with Russ but made a few changes as I wanted more height and width for trees and an aquaculture system ” says Brian Vakoc “I also shifted slightly off the path the sun travels in winter giving us a full day of light In the summer the sun travels over the top of the greenhouse providing more indirect heat ” Other changes in the Finch design include a narrow flat roof that holds thermostat-controlled louvers as well as louvers lower on the rear wall for increased airflow “The cold hasn’t been as much of a threat as excess heat on warm sunny days ” notes Vakoc Vakoc installed a manifold system in the ground with the idea of storing excess heat from the ceiling and then drawing it back in as needed at night He stacked concrete blocks in four locations in the 250-ft loop of fourteen 4-in corrugated black pipes He laid a drain field cover over the blocks to reinforce them The idea was that if one or more of the pipes between manifolds got plugged the air from the others would mix in the cement block voids and then continue through the next section of 14 pipes The pipes have proven more than adequate to supplement heat from the sun in the 25 by 55-ft greenhouse Finch’s most popular design is 72 by 17 ft wide Vakoc’s extra width gives him room for two 4-ft wide vegetable beds front and rear and about 19 ft between for trees on one half and an aquaculture system on the other Vakoc also left room for a 3 1/2-ft walkway between the front bed and the aquaculture system He used 2 by 6-in boards for framing the rear wall with iron cross supports It is insulated with dense foam between the uprights The first 5 1/2 ft of the rear wall is vertical with the next 13 ft angling in slightly to peak at 18 1/2 ft just north of center The front face of Lexan Thermoclear is framed with 2 by 2-in studs with 1 by 1 1/2-in purlins “The front face is one slope with no curvature to it ” says Vakoc “It’s more vertical than Finch’s to capture more solar heat around the winter solstice ” The east and west walls were framed with wooden 2 by 6’s Vakoc fabricated three windows using Lexan Thermoclear Like the overhead louvers they open automatically with an actuator The flat roof is about 2 1/2 ft wide and covered with metal roofing from an old corn crib “The aquaculture system consists of one large ICB tote for a fish tank Four ICB totes with gravel will eventually hold plants with a bell siphon to raise and lower water levels as well as 55-gal barrels as a water reservoir ” says Vakoc “We’re still tweaking the pump ” The vegetable beds are poured concrete walls with earthen floors The front bed is 26 in wide with the top lower than the outside ground level The rear bed is 4 ft wide with its top about a foot below the outside surface Both are about 24 in above the surface the trees are planted in Vakoc uses a 10-in fan to push air through the tubes when additional heat is needed No fan is run during warm weather on the advice of Bill Ihm a Finch greenhouse owner in western Nebraska “Bill helped me a lot with my learning curve ” says Vakoc “He shared that he had left his fan running in the summer and the warm humid air condensed when it hit the cool surface inside the tubes His tubes filled with water and he had to dig them out and put in new tubes ” Contact: FARM SHOW Followup Brian and Zoe Vakoc 88237 523 Ave Verdigre Neb 68783 ph 402-841-0936; bzvakoc@yahoo com

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