This section is from the book "The Gardener's Monthly And Horticulturist V24", by Thomas Meehan. See also: Four-Season Harvest: Organic Vegetables from Your Home Garden All Year Long.
To "William H. B.," of Independence, Kansas, it may be said as follows: Any system of warm air-heating operates on such a delicately-balanced principle that the out-of-door winds easily, and usually, upset and frustrate it. The system by flues and hot water pipes in a greenhouse, as ordinarily seen, resembles the hot-air apparatus too nearly. Heating by steam is the best known system where distribution of heat is an important item. It may not be cheap, but it will be manageable. Heat can be carried through a small opening, about every form of object, to every place, and no fear of its nonarrival in a well made apparatus. No fear of outside gales blowing it all away from one side of the building. The only effect of any extra demand at any point being to cause more steam to be used there and a greater demand to be made on the boiler by those pipes. If I were consulted as to what system of heating to use in a greenhouse, the point being to secure that best adapted to that purpose, I should at once say, " Steam, of course." So perfectly does it seem to me to be adapted to the requirements of the case, as I understand them.
As direct answers to the questions submitted one can say if wood is used to make steam, it will need some attention during the night, not more than flues and likely not as much. I am not aware of any wood-burning steam apparatus now advertised that will run any great length of time without attention, but have no doubt such a demand made on almost any good maker would be satisfactorily supplied. If coal is used, hard or soft, an apparatus can be provided that will take care of itself for almost any night, certainly any but the worst. Such apparatus needs but little attention at any time.
In answer to the second question I would say that whilst steam pipes cannot be raised and lowered at pleasure (far from it), steam heat can, which I suppose is what is wanted. This might be readily inferred, perhaps, from the first paragraph.
As to the hottest point, it can be made to be hottest where you want it.
The dwelling and all the other buildings for a mile (or more) around can be heated by the same boiler if you want to pay for it. No impracticability about that usually.
Use the old boiler if it has the capacity. That is the question. But it might cost more to use it in a well-constructed apparatus than another would.
Set the boiler wherever you want it. so far as horizontal distance is concerned. Look out vertically. It would do in the greenhouse, as suggested, if low enough. It could be built in with brick and covered with sand, so as to keep the local temperature down. I do not advise this, as you cannot see what is happening to your boiler.
Pressures are carried, in my experience, up to sixty pounds, guage pressure. There is no reason, but cost, that I know why they cannot be carried higher. This is not the direction in which to look for economy though. The economy may be expected at just as low a pressure as the apparatus can be worked, say from two pounds to five pounds guage pressure. There was put in an apparatus, a few years ago, under my charge, that worked well under five pounds and under sixty pounds.
The steam may be carried as many miles as you will need, if you have rise and boiler capacity enough.
Now, while all this seems easy, and looks as if one might readily have just what was wanted, I wish to offer one word of caution. It isn't so easy to any one not qualified to prepare the necessary apparatus and erect it in a proper manner. Not much worse blunders can be made in any matter of equal importance than in steam-heating. No one, not well qualified, should ever be allowed to have anything to do with the control of such work. Apply to parties of well established reputation lor character and knowledge and skill. I don't want a job, and may be I have not the requisite character, knowledge or skill, as I certainly have not the reputation. As this communication costs nothing, it may be found worth it.
When I told my wife I was writing a short item for the Gardener's Monthly she said she thought I was writing the Gardener's Monthly itself; so I hasten to stop. Print what you please and no more - or none.