This section is from the book "Indoor Gardening", by Eben E. Rexford. Also available from Amazon: Indoor Gardening.
WE do not mind drafts, and air-currents, and the liberal admission of cold air through cracks and crevices about windows and doors, and the floors, in spring and summer and early fall, but we must not forget the great difference between the temperature of those periods and that of winter. A small crack may let in cold enough, when the thermometer runs low and the wind is from the right quarter, to offset all the warmth sent out from a good-sized stove, after its drafts and dampers are adjusted for the night. If there are many such cracks and crevices, cold enough may come in to freeze our plants. Therefore, the thing to do is to go over our rooms carefully, and see that they are made proof against the admission of the enemy. And the time to do this is while the weather is pleasant, for much of the work may have to be done outside, and work done when the fingers tingle with cold is quite likely to be work poorly done.
Look to the window-sash. If you find panes loose, and putty cleaving away, have the glass reset.
Look to the framework of the window, and make sure that the sash fits it snugly. If it doesn't, see that it is made to do so. Tell whoever does your carpenter work that he must aim to close every point against the cold. This means snugly fitting joints as well as tightly fitting glass.
Examine the baseboards in the rooms where you propose to keep plants. They may look to be all right, but do not be satisfied with outside appearances. Light a candle and hold it where drafts, if there are any, can affect its flame. This will tell you where to have the work done. The carpenter, if he understands his business, will know just what to do to correct the faulty conditions. There may be as many drafts about the doors as there are about the windows. Generally there are more. Have them fitted with weather-strips.
It is a most excellent plan to have storm-sash put on all the windows in the room. If this is done, and the outer sash is made to fit the frame well, and is held firmly in place by long screws that will prevent it from springing away from the wood it should hug tightly, your plants will not have to be moved away from the glass on cold nights, for the airspace between the two thicknesses of glass will act as a non-conductor of cold. It will be perfectly safe to leave your plants with their leaves against the glass of the window in the coldest weather.
All these precautions work together for the safety and well-being of your plants, and they pay for themselves by the fuel they save.
Examine the foundation-walls to make sure they have not cracked or crumbled in such a manner as to allow cold air to pass through readily. If any cracks are discovered, plaster them up. More cold comes into a room through its floors than most persons have any idea of, and the only way to keep it out is to keep the foundation-walls in perfect repair. If the house does not stand on a stone foundation, banking must be resorted to. Set up boards and fill in between them and the house with sawdust or dry soil. Before putting in either, it is well to nail two or three thicknesses of sheathing-paper over the inside boarding. Let it extend up over the lower six inches of the house-walls, fastening it in place by a strip of wood, or something that will hold it firmly and evenly against the clapboards.
Some reader of the above advice may say: "This doesn't fit in consistently with advice given elsewhere. If these instructions are followed, we would have an almost air-tight room in which to grow plants. He has had a good deal to say about the importance-the absolute necessity of fresh air. How can we reconcile the two theories?"
I propose to do so in this way. Have the tinner make you a pipe two inches across, and as long as your window is high. Let there be an elbow at the top, of the same size as the other pipe, and long enough to extend through the wall of the house. Then have your carpenter put the pipe in place by boring or cutting through the wall. The short length of pipe will project into the room. The long piece of pipe will extend down the wall on the outside. Leave this pipe open at the bottom. Have a cap fitted to the short piece reaching through the wall. Whenever this cap is removed, cold air will rush into the outer pipe and be discharged into the room, in great quantities, but its place of admission will be so far up the wall that it will come in contact with the warm air in the room, and all its chill will be lost, even in the coldest weather, before it reaches your plants. There should be a window on the opposite side of the room so arranged that it can be lowered from the top, or an outlet-pipe can be put through the wall there. Open the window or pipe when the inlet-pipe is in operation, and the foul, overheated air of the room will be driven out before the inrush of fresh air. In this way you can keep your plants supplied with all the fresh air they need, and, in doing so, you will be benefiting yourself. In ordinary weather both pipes can be left open and the air in the room will be constantly changing, therefore always comparatively pure, and vastly more healthful than the air in rooms not arranged for such a supply.
I am well aware that many of my readers may not feel able to afford the expense which some of the suggestions made above call for. But they can do a good deal in the way of protection for their plants without any expense whatever. Openings in the inside walls, and about the window-frames, can be closed by pasting strips of paper over them. A strip of bleached cotton cloth is better, however, as it is not so likely to peel off, and it will never crack, as paper often does. Make your paste good and smooth, by boiling it well, but do not have it very stiff.
The cracks along the floor, where the latter has settled away from the base-boards, can be closed snugly wTith a strip of concave moulding. This is narrow enough to be very flexible, and therefore it can be fitted tightly to the corner formed by floor and base. Be sure and use nails long enough to hold it securely in place.
Similar strips of moulding can be fitted to the angles formed by sash and frame, outside. Or, good results can be secured by laying strips of felting, or some thick cloth, over openings, and tacking on lath to hold them in place. This can be done inside, and the expense of the concave moulding advised can thereby be avoided, if one is not particular about the looks of the thing. The point to aim at is-exclusion of cold. It doesn't matter just how you exclude it, so long as you keep it out. If large pieces of plaster are broken from the walls, paste a square of cloth over them and allow it to get dry before you cover with paper. If snugly drawn when applied, it will be as smooth as a drum-head when dry, and no one would suspect a broken wall behind it.
 
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