Care must be taken in watering plants in winter. Those which are dormant, or are making but little growth, will require very little water. Those in active growth will need more. The only way to tell how much to give is to watch your plants closely, and observe the effect of the applications given. When the surface of the soil takes on a dry look it is safe to conclude that the roots of the plant in the pot have made use of most of the moisture in it, and that more water should be given. Then give enough to make the soil moist all through, and withhold further applications until the dry look appears again. Never form the habit of watering your plants every time you happen to think about it, and then apply just enough to make the soil look wet on its surface. If this is done you will never grow good plants, for only the surface roots will get the moisture they need. Have a stated time for watering, and let the appearance of the soil govern the amount used.
XV
THE INSECT ENEMIES OF PLANTS
Every woman who attempts to grow flowers in the house will sooner or later have to wage warfare against insects.
Perhaps the first battle will have to be fought with the aphis, or plant-louse. This insect sucks the sap—the life-blood of the plant—from stalk and leaf, and soon, if let alone, it will exhaust the vitality of the plant to a degree that is wholly incompatible with health. In fact, if allowed to have its way, it will kill your plants, for it propagates its species with such rapidity that a plant will soon be literally covered with them. We used to kill off these insects by fumigating the plants infested with them with tobacco smoke, and in doing it we made ourselves about as sick as the insects were, and the nauseating fumes of it clung to everything in and about the house for days. Nowadays we make use of the nicotine principle of tobacco in our warfare against the aphis, but in a manner that leaves out the objectionable features of fumigation. Tobacco manufacturers have prepared an extract of the nicotine in the plant, and put it on the market under the name of nicoticide. All we have to do when we want to make use of it is to put a small quantity in water, and spray our plants with the mixture. Every aphis that it touches will die, and those that it fails to reach will take the hint that they are not wanted and that their presence will not long be tolerated, and the first you know they will have disappeared.
Instead of waiting for the attack of the enemy I consider it good policy to anticipate it by frequent applications of the tobacco-bath. It will be found easier to keep the enemy away than to rout it after it has established itself on your plants.
The red spider is another insect that does deadly work in the window-garden, especially in rooms where the temperature is high and there is little moisture in the air—a condition that generally prevails in the ordinary living-room. This pest is so small that its presence is seldom suspected until considerable injury has been done to the plants it works on. If you notice that leaves are turning yellow and dropping off, and that more and more of them fall each day, you had better look into the matter. Examine some of the fallen leaves. If you find tiny webs on the under side of them you may be quite sure that the spider is responsible for the condition your plants are in. Look at some of the leaves that are yellowing, but have not yet let go their hold, and you will be quite likely to find little red specks on them. These specks resemble grains of fine Cayenne pepper more than anything else. Watch them for a while and you will find that they are living organisms. It seems hardly possible that such tiny creatures can do much harm to a strong plant, but the fact is that there is no more voracious enemy of plant life in existence. Here the tobacco-bath does not come in play. Cold water is all the insecticide we need. Spray it over every portion of the infested plants daily, until they again take on a healthy look and begin to grow. The spider will not stay long in a moist atmosphere. Make it moist and keep it so by the liberal use of water sprayed upon your plants, and you will have very little trouble with this dangerous pest. But if you neglect to use water regularly and freely the probabilities are that your window-garden will look rather sickly by spring.