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How to Heat Your Hothouse: 1841 and Later

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When Robert Buist mentioned radiant hot water floor heat for hothouses, it was an innovation; the first records of such a system in U.S. hothouses is in 1839. By 1847,  Charles M’Intosh’s The New and Improved Practical Gardener, and Practical Horticulturalist boasts an appendix on the new and improved tank system for bottom heat.

The boiler/radiant floor systems must have caught on, because by 1875, when Peter Henderson wrote Gardening for Pleasure,  hot water heating systems for hothouses seem to have been an industry standard. “Although we describe flues as a means of heating greeenhouses or graperies, they should be used only on the score of economy; whenever one can afford to have the heating done in the best manner, by all means let it be done by hot water.”

Henderson points out that the hot water system takes less attention, and is easier to manage. (You get the feeling that the hothouse owner is probably not the person who has to manage these systems.) And he mentions the same dangers of smoke and gas that Buist alluded to. By now, commercial boilers are available, ready-made for the purpose; he recommends Hitchings & Co. in New York as purveyors of the best.

Henderson, a very popular garden writer, wrote widely, on every subject that had to do with plants. He was known for his agricultural treatises as well as his ornamental gardening works, and he must have had some wealthy clients, since he uses two pages of diagrams and description to outline a combined hothouse and greenhouse, totalling 20 x 100 feet (about 7 meters x 30.5 meters), and costing about $3,000 USD to construct in 1875.

When I looked up this figure on Measuring Worth  to see what that meant in modern terms, I got involved in a whole other adventure. The relative worth of something can be measured in a number of ways. The Consumer Price Index measures relative cost by taking the price of normal household items and adjusting for inflation. In those terms, the 2007 price for Henderson’s greenhouse would have been $58, 461.09.  But using the Unskilled Wage Rate, which determines the cost of something in terms of the amount of work it would take to produce, the same greenhouse/hothouse would cost $392,400. There are six indicators in all, and the highest price comes from relative share of the Gross Domestic Product. I admit, I didn’t get exactly how that indicator works, but I did understand the price: a mere $5,076,124.62 for this greenhouse/hothouse combination.

However you look at it, such a project was for the wealthy to the insanely rich. And insanely rich was what James Lick, resident of San Francisco, appears to have been. He left behind 12,000 square feet (3657.6 square meters) of greenhouse fashioned from wood and glass when he died in 1876, and a group of businessmen bought it and donated it to the San Francisco Park Commission. When I visited that renovated Flower Conservatory in Golden Gate Park last year (2007), I was struck by the design of the steel walkways in the floor, so I took pictures of them (an example of what I saw is in the photo at the top of this page). Now I realize that what I was looking at was a much-upgraded example of Buist’s “pathway...which…may be a casting of iron, or wooden slats, fancifully put together, at least six inches above the flue.”

One of life’s little satisfactions: discovering more of the story behind something.

{ 2 comments… add one }

  • Nancy Bond December 27, 2008, 2:14 pm

    Aren’t those beautifully intricate grates?! This has been such an interesting read.

  • Pomona Belvedere December 30, 2008, 5:14 pm

    Nancy, I’m glad you were entertained by this; in winter I tend to be much more involved in fantasies of gardening.

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