This section is from the book "The Gardener's Monthly And Horticulturist V18", by Thomas Meehan. See also: Four-Season Harvest: Organic Vegetables from Your Home Garden All Year Long.
In this part of the world window plants are nol given their summer airing until May, but every opportunity is taken to let them have all the open air possible, by opening windows and sashes wherever practicable. People often complain that plants from greenhouses are too tender to stand the open sun, but it is only because they have been too much confined. If any plants growing in pots are yellow, or in anyway sickly, it is as well to prune them severely and plant for a year in the open ground. If they have insects on them these should be cleaned off before planting out, or they will'increase under our dry summer sun. The red spider is best treated to a syringing of warm soap suds, and then to be dusted with sulphur; and the scale insects should have a painting with whale oil soap, and' some say linseed oil. Many plants will have to be kept in pots all summer, and these are best set in partial shade. There are few more desirable room plants than the Ivy and Periwinkle in their numerous varieties. These should be potted now, and grown all summer. There are many things nearly, or quite hardy, that are not often kept in pots, but which would make good things for room culture, and these should be potted now.
Of these we may name Cotoneasters, Mahonias, Berberis, Euony-mus. These are very easily managed, and it seems to us that for those who have had little experience in plant growing, or whose conveniences are limited, it is just as feasible to have beautiful things easy to grow, as beautiful things that are difficult.
During the summer one may have rooms prepared for winter window-plants, and much may be done by arranging shutters so as to make double windows, to keep out the cold. In this connection read the following good hints from the Builder;
"Nothing is more effective to keep out cold than double windows; the layer of air between two panes of glass is a good non-conductor of heat, and can only transmit it from the inside outward by convection, that is, by a circulation of the inclosed air, which will descend along the outer cold window pane and ascend along the inner warm pane. The radiated heat, which, at temperatures below 100° Fah., is very weak through glass, is of course smaller still through double glass; then the inconvenience of glass becoming covered with frost during cold weather, is done away with, if the inclosed air is dry.
"Some time ago we communicated a suggestion, made by some builder, to insert two panes of glass, one on the outside and one on the inside of the same frame, having rabbets on both sides; this may do for economy, but is subject to the objection that the inside cannot be cleaned without taking the glass out, and the fact is that in the course of time it will in some way or other get into such a condition as to need cleaning; then, when the glasses are so close together, the protection against the outer cold is less effective than if a greater mass of air is included.
"In very cold countries, like Russia, Sweden, or Canada, the need of such protection is more felt than with us; but even here it is often adopted in exposed localities, when the parties can afford the luxury. Thus all the houses on Brooklyn Hights, enjoying the magnificent view of New York harbor, and those on Washington Hights, enjoying the view of the Hudson river and the Palisades, are fully exposed to the strong and cold blasts of the northwest winter winds, and are all provided at the west and north sides with double windows, the absolute necessity of which has become more and more evident for the comfort of the inmates. Such a double window may serve another purpose, and be used as a little greenhouse; when exposed to the sun, the solar heat is stored up in them, and in France some parties grow different plants and even grapes in them in winter."