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
USA

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: http://www.shieldsgardens.com/
Westfield, Indiana 46074, USA
Tel. ++1-317-867-3344 or toll-free 1-866-449-3344 in USA