Greenhouses in Winter. Was: Cold winter miscellany

J.E. Shields
Thu, 10 Dec 2009 05:47:12 PST
I've had some sort of heated greenhouse since about 1971.  Indiana is cold 
in winter, and I had too many pots to bring indoors for 6 months.  But 
Kathleen is right -- greenhouses are troublesome and expensive.

We now have four greenhouses -- three small home-greenhouse sized units 
each about 250 sq ft (ca. 23 sq meters) and one 2700-sq ft (ca. 250 sq 
meters) commercial unit.  Heating them all in December and January can be 
expensive.  The temperature outside right now is 9°F (ca. -13 C) and the 
wind is blowing.

The  250-sq ft cold greenhouse for winter-growing South African bulbs is 
especially hard to heat.  Strong winds tend to blow out the gas pilot 
lights on the millivolt gas heaters (they use no electricity from the 
mains, in case of power failures); and electric heaters in this kind of 
weather can pop the circuit breakers in the wee cold hours of the 
morning.  We are OK in this greenhouse so long as the inside temperature 
does not drop much below 32°F (0 C) for very long.

The big greenhouse, full of clivia plants, has two large overhead gas 
furnaces that work fine and are protected from power failures by a large 
natural-gas fueled emergency generator.  I sometimes wonder whether, 
knowing 4 or 5 years ago what I now know, I would have built that big 
greenhouse?  If lots of the Clivia bloom on time in March, I'll probably be 
very happy I built it.

Jim Shields
in cold and windy Westfield, Indiana

P.S.  To convert square feet to square meters, multiply  sq ft X 0.0929

Jim Shields             USDA Zone 5             Shields Gardens, Ltd.
P.O. Box 92              WWW:
Westfield, Indiana 46074, USA
Tel. ++1-317-867-3344     or      toll-free 1-866-449-3344 in USA

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