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House Plants - In Sickness And Health

( Originally Published 1923 )

The ideal conditions for house plants are practically the same as for human beings; that is, a temperature of about 65 to 70 degrees during the day time, and 50 degrees to 55 degrees at night. It may not always be possible to maintain this warmth at night, but strive to keep as near it as possible.

Plants grown in a window will invariably turn to the light, and unless the position is frequently changed, they will become one-sided. To avoid this, turn the plants half-way around each day, so that each half of the plant will get an equal amount of light.

During the winter have a care that none of the leaves of the plants touch the glass during the night or when there is frost out-side, because it will at least chill, and maybe kill them.

On very cold nights move the boxes or pots away from the window and put news-papers in front of the glass, but leave a dead air space between.

The next consideration is fresh air; keep the rooms well ventilated, i. e., have a window open somewhere in the room, preferably on the opposite side from the plants, for they cannot stand draughts. When a room gets too warm and too dry, the plants transpire an excessive amount of water faster than the roots can supply it from the soil but, worse still, the surface of the soil itself is dried out, and even the pot as well. Thus an irreparable injury is done before the owner realizes it.


When plants are grown in an abnormally high temperature, with moisture, the growth is forced, and, being soft, is easily injured. A strong draught, even if only 10 degrees or 20 degrees cooler than the surrounding air, will seriously chill plants in this condition. The result will be that plants like the geranium and heliotrope will turn yellow and drop their leaves; with palms, the tips of the leaves will turn brown. To get the plants back into proper condition will take months of careful attention, and in the case of palms or ferns it will take a year prefer-ably at the florist's.

To give the atmosphere the proper amount of moisture have a small dish on the radiator, register, or stove, and keep it full of water. Most hot air furnaces have a water compartment inside the jacket which holds about a pailful. Under ordinary conditions this will need filling only once a day, but during the coldest days of winter, when the firing is heavy, it may be necessary to fill it twice.


The second most exacting requirement of plants is watering. Too much water will make the soil sour; with too little water the plant will wilt. The effect of either will be yellowing and dropping of the leaves. It is easier, however, to drown a plant than to kill it by drought. No hard and fast rule for watering can be made. Plants may need water twice a day or only once in two days. The best way to determine whether a plant is dry is to rap the pot sharply with the knuckles of the hand. A hollow, or ringing sound shows that the soil needs water; a heavy, dull sound indicates that it has sufficient moisture. Usually you can tell whether the soil needs watering by looking at the surface. If it is dry and powdery give water.

The common fault in watering is not doing the job thoroughly. Never give a little surface sprinkling. The best way, if convenient, is to take the plants to the sink or bath tub and give the soil a good watering, allowing the pot to stay in the sink until the surplus water has had a chance to drain off. If it is impossible to do this, have a saucer under each pot and ten or fifteen minutes after the watering go around and turn out all the water standing in the saucers. Never allow water to remain in the saucers as it will prevent aeration through the hole in the bottom of the pot, and also it will rot the roots. When plants are kept in jardinieres people often grow careless, let water collect in the bottom and then wonder why the plant is not doing well.

If by any chance the ball of earth should become very dry, plunge it in a pailful of water and let it stand five or ten minutes until the whole ball is soaked through. When the air-bubbles cease to rise the ball is generally thoroughly soaked. Pouring water on the top of the soil of a dried-out pot plant is generally useless because the ball contracts in drying and leaves a small space between itself and the pot down which the water will run.


Bathe the leaves frequently to remove dust, which will inevitably settle on them and choke up the pores. When the plant is in the sink or tub a hand syringe can be used to spray the foliage without wetting the floor. If this is inconvenient then carefully rub over the surface of each leaf with a damp sponge. If necessary, a little soap may be used in the water.


Many amateurs do serious injury to their house plants by not leaving well enough alone while growth is dormant, or almost so. It is simply folly to fuss about with potted plants at that season. Do not disturb the roots at all during the winter, for most plants are resting and cannot quickly put out new roots. This - is particularly true of such decorative plants as palms, rubber plants, and ferns, which can be shifted or fed with fertilizers only in summer. Soft wooded plants, like geraniums and heliotropes, are not so easily injured by transplanting, but even so I prefer to put them in large enough pots in the fall so that they will not need shifting until spring. If they should need extra feeding, on account of large growth, it is much better given in liquid form.


The best form of liquid plant food is made from cow manure at the rate of two bushels to a barrel (fifty gallons) of water because there is no danger of burning the roots; horse manure and sheep manure are also good, but they must be used very weak (one bushel of the former, and one-half bushel of the latter to a barrel of water) or they will injure the roots. I have used horse manure very successfully when the liquid was the colour of very weak tea. These are mussy to handle. Neater are the special plant foods put up in tablet, liquid, or powder forms. These can be bought in the local stores, or ordered from the catalogues of seedsmen.

If you wish to make a good liquid fertilizer at home the following recipe will give satisfaction. To one gallon of water add eight ounces of nitrate of soda, sixteen ounces of monobasic calcium phosphate, and ten ounces of sulphate of potash. For use dilute it, using one part of this stock solution to thirty parts of water, and use it about once a week.


Perhaps the greatest enemy of plants grown in houses heated by hot air furnaces or coal stoves is coal gas. An otherwise imperceptible trace of it in the air will cause the leaves of some plants (as Jerusalem cherry) to drop off promptly. With a good chimney draught and with proper regulation of the dampers when attending to the fire there should be no trouble from this source.

Illuminating gas is almost as bad as coal gas. The slightest trace will retard the development of new leaves on all but the toughest-textured plants, like rubbers and palms. Such thin-leaved plants as geranium, coleus, heliotrope, and begonia succumb quickly. When gas is present in very small quantity the plants do not necessarily die but growth is stunted and the flower buds wither when beginning to show colour, looking much as though they had been chilled.


The commonest insect enemies of house plants are the plant lice or aphides. Look for these pests on the under side of the leaves where they suck the sap. Against them use tobacco water or soap suds. Tobacco water can be made from tobacco "stems" which can be bought from almost any florist or seedsman. Put a large handful into a gallon of warm water and let it stand for twenty-four hours, then dilute it to the colour of weak tea and syringe the foliage, being careful to hit the under side of the leaves. A simpler way is to buy a tobacco extract and follow the directions on the package.

If soap suds are used rinse the plants with clear water afterward.

If the plants are grown in a conservatory, or a room that can be completely shut off from the rest of the house, fumigating is the easiest and best method of fighting the aphides.

For this tobacco stems can be used, but the tobacco preparations offered in the stores are easier to handle, according to directions.

One can now buy sheets of paper which are impregnated with tobacco, and all that is necessary is to distribute enough sheets about the room to give the required density of smoke and set them afire.

Whatever method is used select a quiet night for it and shut the room tight. By morning all evidences of the smoke will have disappeared. Then syringe the plants to knock off the aphides. Badly infested plants will need fumigating twice a week on successive nights.


A simple fumigating device may be made from a soap box and three or four paper flour sacks. Turn the box upside down and in the bottom bore a lot of one-inch holes. In one end of the box make a hole big enough to put a saucer through. Cut open the sides of the bags in such a way that they can be pasted together again to make one large bag, the open end of which will fit over the box.

Now place the plant or plants to be fumigated on the still inverted box and draw the big paper bag down over them and tie it securely to the box with a string. In the saucer place one of the forms of tobacco ground tobacco, or tobacco soaked paper or tobacco punk light and place it inside of the box. Be very careful when fumigating the plants not to use the tobacco too strong or the leaves will become scorched. When the sack has become sufficiently filled with tobacco, remove the burning tobacco from the box. Let the plant stand half an hour with the sack on, then remove it, and syringe the plant with water to knock off the stupified aphides. Two light fumigations on succeeding days are much less liable to injure the plant than is one strong fumigation.


An aphis sometimes attacks the roots, causing the plants to take .on a sickly or yellow colour. It is easily found by digging down near the base of the stem, and is attacked by watering with the tobacco water already described. If this does not kill the aphides the plant must be removed from the soil, the roots washed with whale-oil soap (one quarter pound to two gallons of water). Then rinse and repot in fresh, clean soil.


Next to the aphides in destructiveness is the red spider, a very small red mite which can scarcely be seen by the naked eye. It lives on the under side of the leaves, but its presence can be readily told by numerous minute yellow spots on the upper side. Like the aphis the red spider subsists on the plant's juices. It thrives in a hot, dry atmosphere, and its presence is a sure sign of insufficient moisture. The conditions ordinarily found in living rooms are very favour-able for this pest. The remedy is obvious: syringe the plants with water, applying it on the under side of the leaves, and with considerable force because the spider is protected behind a web.


Mealy bug, which is almost always present in the greenhouse, sometimes infests house plants, too. This insect looks like a small tuft of white cotton, and is found on the under side of the leaves and in the joints. A strong stream of water will usually wash it off, but if that fails use kerosene emulsion or fir tree oil, which must be diluted according to the directions on the package, and applied as a spray or with a feather. Alcohol has also been successfully used when there were only a few mealy bugs. With a feather or small stick put one drop on each bug, and he will immediately succumb.


Very often scale insects will be found on the leaves of palms, ferns, rubber plants and cycads. The commonest one is the brown scale. It is one-quarter to three-eighths of an inch long, and nearly as wide, and its hard, convexed shell is dark brown in colour. The other scale commonly found on greenhouse plants is white, and about the size of the head of a pin.

Both these scales can be removed easily by spraying with whale oil soap, kerosene emulsion, or fir tree oil.


Sometimes plants are infected with thrips, which eat the epidermis of the leaves. They are small, slender, brown or black insects, about one-fourth of an inch long, and are easily controlled by any of the contact insecticides already mentioned, or by Paris green one teaspoonful to twelve quarts of water.

If angleworms infest the soil in the pots they may easily be got rid of by watering with lime water which may be made as follows: To ten or twelve quarts of water add one and one-half to two pounds of fresh lump lime, letting it stand for a couple of days, or until the lime has slacked and the water cleared, then pour off the clear water for use. Several waterings with this at intervals of three or four days will drive out the worms.


There are numerous freak remedies some-times suggested for ailing plants, varying from applying beefsteak and castor oil to the roots, to coating the leaves of such plants as rubber trees and palms with milk or olive oil.

I never could understand why plants should need castor oil; in fact, it is a decided detriment, for it will clog the soil. When the plant begins to look sickly, look at once for the conditions which have caused it; it may be one of the causes mentioned in this chapter. There is a popular fallacy that if iron filings are put in the soil in which sickly plants are growing, their youth will be renewed. There is sufficient iron in any soil for plants, and any addition to the soil will be only a waste of time and money.

I can readily understand why wiping off the leaves with milk or other oily substance is resorted to; it makes the surfaces of the leaves shine. Every time this is done it is at the expense of the plant's health, for the fatty substance will surely clog the pores of the leaves, retarding or completely stopping the transpiration. The leaf of a healthy rubber plant or palm will shine if the dust is wiped off each day. This should always be part of the daily routine in the care of house plants.

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