This section is from the book "The Gardener's Monthly And Horticulturist V21", by Thomas Meehan. See also: Four-Season Harvest: Organic Vegetables from Your Home Garden All Year Long.
In the February number of the Monthly appears as sensible an article upon the heating of greenhouses as I have seen for some time. F. W. Poppey, the writer of the article, evidently has given the subject much thought. Last Summer I started as an amateur, and the first tough point to settle was the boiler. After looking into the merits of all the patent boilers I could hear of, my decision was to cut loose from all of them and put in an ordinary locomotive boiler of from ten to twelve horse power, and I venture to say the same amount of glass is nowhere else heated with the same amount of fuel unless this style of boiler is used. I am heating nearly 6000 feet of glass, and carry a temperature of from 40° to 80° in four houses. Judging from the amount of fuel on hand, the cost to date for coke and coal will not exceed $60. The cost of the boiler with alterations ready to connect to 4-inch pipes, was S175, delivered and put in the pit. They may be bought as low as $50, but the above is a fair price for one of 12-horse power as good as new.
The advantages of this boiler over all others for making steam are too well known to make it necessary to describe them here. If it gives steam quicker than any other boiler, of course it heats water faster. It requires no building in. To get all the heat possible the boiler should extend into the greenhouse (in the pit), and then wall up flush with the face and feed from the outside. The brick flue extends the length of the house, giving it as much rise as possible. On account of so much heat being taken up by the water, it requires rather more rise than if water was not used. That portion of the pit extending into the greenhouse should be large enough to admit of a person getting all around and under the boiler to make repairs, clean out, etc. I am well aware that a wrought iron boiler will not stand the neglect that a cast iron one will. But with care the life of a steam boiler is about fifteen years; and if these boilers are treated the same as the boilers on our Monitors are, when not in use, they will last longer.