This section is from the book "The Gardener's Monthly And Horticulturist V23", by Thomas Meehan. See also: Four-Season Harvest: Organic Vegetables from Your Home Garden All Year Long.
C. T. W., Fairview, Ky., says: "Will you please give your readers some information on the use of hot water tanks in the propagation of plants. What plants are thus rooted and the temperature of water; and especially, are roses successfully rooted thus?"
For a small propagating tank, the simplest boiler is that described in our seventh volume, as in use by Mr. Saunders, at Washington, which we reproduce here.
The furnace is placed opposite the middle of the house, and has also some peculiarities of construction, which we did not have fully explained, but our attention was attracted to the simple mode of heating the water in the tank which underlies the bed. Within a few feet of the furnace, a small piece of bent four inch pipe is inserted with two arms, one of which is the flow and the other the return. This pipe altogether is about fifteen feet in length, nine feet of which lies in the flue; and the heat, as it passes this pipe, is sufficient to maintain an average temperature of one hundred and ten degrees in the water, with moderate fire. If required, we understood that it could be raised to one hundred and twenty degrees with ease. The shape of the pipe is as shown in this sketch, the bent portion being in the flue, which is represented by the horizontal lines. The simplicity and cheapness of this arrangement is manifest. Any plumber can make the boiler (for such it really is), and any laborer can fix it in its place. Its cost can always be readily ascertained, being little more than the cost of so many feet of three or four-inch pipe.
It can also be extended, and several tanks heated from the same fire; a side tank forty feet by two feet is in this case warmed by a small piece of two-inch pipe, let down through the top of the same flue that contains the four-inch pipe above illustrated.
[It may be added that the two parallel lines form the flue A, and that the furnace is built so as to closely connect with the turn in the pipes. The tank for the hot water is above (B). This may be made of wood, the sides having thick brown paper and white lead put between, before nailing together. This keeps the tank water-tight. The cover for the tank is best of thin slate. The shallow tank is divided in the middle, except at a small place to admit of the cooled water going to the return side, as shown in the above cut. a is where the water enters, and flows along b b, returning to the furnace at c.
Anything that requires heat to root, succeeds in-such a tank; provided the cutting can have partial shade for a little while. Light is unfavorable to the production of roots. - Ed. G. M.]