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.
Many of our readers have only a few window plants. These are often kept too warm, too wet, have too little sun light, and have too many insects. In towns, in addition to all these, they have often too much of the fumes of burning gas. Leaks or escapes from the gas pipe is a well known injury to plants, but it is not so well known that plants suffer, though in a less degree, from the common burning of coal gas. The trouble with most room cultivators is to know when plants get too much attention. Too many insects are easily known, one - a single one - is by far too many. We still think there is nothing like coal oil to destroy all kinds of insects. A very little - just enough to make a colored scum on the surface of a tub of water is enough, and in this the insect covered plant may be dipped, inverting the pot and plunging only the plant, and not the pot of course. If too much oil is used the plant may be injured. Too wet is when a plant seldom gets dry - a healthy plant should get dry, and have light dry looking surface soil, every two or three days; as to heat, a temperature of about 55° or 60° is best for room plants, below that they do not flower freely, above they grow weak, especially if they have not a great deal of sunlight.
Indeed heat should be in proportion to direct sunlight on the plants.
Where the air is dry in rooms or greenhouses, frequent syringings are of much benefit to plants. Besides, cleanliness keeps down insects and checks disease in plants as in animals. Most old fashioned lady gardeners (and may we ever bless them for the many lessons they have taught us,) take every opportunity to set their window-plants out of doors whenever a warm shower happens to occur. In Winter a rain at a temperature of 40° or 45°, which often occurs, might be called a "warm shower." Cold water does not have half the injurious effect on plants that cold air has. When plants get accidentally frozen, the best remedy in the world is to dip them at once in cold water and set them in the shade to thaw.
It is better to keep in heat in cold weather by covering, where possible, than to allow it to escape, calculating to make it good by fire-heat, which is, at best, but a necessary evil. Where bloom is in demand, nothing less than 55° will accomplish the object; though much above that is not desirable, except for tropical hot-house plants. Where these plants are obliged to be wintered in a common green-house, they should be kept rather dry, and not be encouraged much to grow, or they may rot away.
Ferneries are now so deservedly popular, that we must have a word to say for them at times, though their management is so simple, there is little one can say. It is probably their ease of management, and the great results obtained for the little outlay of care, that has rendered them so popular. It should not, however, be forgotten that the cases in which they are enclosed is not to keep out the air, but to keep in the moisture, as Ferns will not thrive in the dry atmosphere of heated rooms. A few minutes' airing every day will, therefore, be of great benefit to them. Decayed wood, (not pine), mixed with about half its bulk of fibrous soil of any kind, and a very small proportion (say a tenth of the bulk) of well-rotted stable-manure, makes a good compost. Most kinds particularly like well-drained pots. This is usually effected by filling a third of the pots in which the Ferns are to grow with old pots broken in pieces of about half an inch square, on which a thin layer of moss is placed, before filling the pots, to keep out the soil from choking the drainage.