In the first place it must be remembered that at best it is hard to get conditions in the living-room that will be suitable for the healthy growth of plants. Every effort should be made to prepare a place for them in which such conditions may be made as nearly ideal as possible: plenty of light, evenly regulated temperature; moisture in the air.
For most house plants the temperature should be 50 to 55 at night and 65 to 75 during the day. An occasional night temperature of 45 or even 40 will not do great harm but if reached frequently will check the growth of the plants.
Air should be given every day when the temperature of the room will not be too greatly lowered thereby. Avoid direct drafts, as sudden chills are apt to produce bad results. Even on very cold days, fresh air may be let in indirectly, through a window open in an adjoining room or through a hall. It is better, when possible, to give a little ventilation during an hour or two, than to rush too sudden a lowering of the temperature by trying to do it all in fifteen minutes.
The amount of water which should be given will depend both upon the plant and upon the season. During the dull days of winter and during the "resting season" of all plants, very little water will be required. It should be given on bright mornings. During early fall and late spring, when the pots or boxes dry out very rapidly, water in the evening. In either case, however, withhold water until the soil is beginning to get on the "dry side" and then water thoroughly. Water should be given until it runs down through into the saucers but should not be allowed to remain there.
Sometimes it will be beneficial to moisten the foliage of plants without wetting the soil. Just after repotting and in fighting plant lice, red spider and other insect enemies (see Chapter XVII) this treatment will be necessary. A fine-rose spray on the watering-can may be used but a rubber plant-sprinkler costing about sixty-five cents, will be very much better, as with it the water will be applied in a finer spray with a great deal more force and to either the upper or under surface of the leaves—a point of great importance.
Plants growing in windows, where the light strikes them only, or mostly, from one side, should be frequently turned to prevent their growing one-sided.
Also do not hesitate to use knife, scissors and fingers in keeping them symmetrical and shapely. One of the greatest mistakes that amateurs make is in being afraid to cut an ungainly or half leafless branch. Instead of injuring a plant, such pruning frequently is an actual benefit.
If neglected, dust will quickly gather on the leaves and clog their pores, and as the plants have no way of breathing but through their leaves, you can see what the result must be. Syringing, mentioned above, will help. They should also be wiped clean with a soft dry cloth, especially such plants as palms, rubbers, Rex begonias. Do not use olive oil or any other sticky substance on the cloth. Always remove at once any broken, dead or diseased leaf or flower. Do not let flowering plants go to seed: nothing else will so quickly bring the blooming period to a close.
Do not try to force your plants into continuous growth. Almost without exception they demand a period of rest, and if you do not allow them to take it when nature suggests, they will take it themselves when you do not want them to. The natural rest period is during the winter. During this time a very little water will do and no repotting or manuring should be attempted.
It is, however, desirable in some cases, as with many of the flowering plants, to change the season bloom, as we want their beauty during the winter. In such cases they should be made to rest during the summer, by withholding water and keeping them disbudded.