With the knowledge that is now being applied to the production of foliage house plants for the market, there is a much better chance of growing them successfully in the home. But they still need proper care.

Almost all of the plants come from Florida, Texas or California. Previously, many were grown in full sun and did not survive for long in the low light intensity of the average home.

Now most of them, particularly those from Florida, are grown in the shade or else acclimated (conditioned) to the low light of the home before being sold.

But if it is too dark in the home, a plant cannot make enough food for sustenance and will soon die.Some kinds need more light than others.

No hard and fast rules can be given because there is no simple, easy way to determine the light intensity.

After being acclimated, most foliage plants cannot tolerate direct sun. The sunlight striking the leaf causes it to get warm and lose water vapor rapidly through the process called transpiration.

If this occurs faster than water can be supplied by the roots, the leaf tissue will become dry internally and the tissues will die.

This is most commonly seen as brown patches on the leaf particularly if the plant is at a right angle to the rays of the sun, causing the leaf to heat more rapidly.

Many kinds of foliage plants can be placed near a window where they will get indirect sunlight for a short period, or else filtered through a curtain which reduces the intensity.

Incandescent lamps can be used to supplement the intensity or amount of light, or used alone as the sole source of light, but the lamps must be far enough away to prevent burning of the leaves.

Fluroescent lamps may supplement sunlight or be used alone as the only source of illumination. The intensity generally is not as bright as that from incandescent.

In the home, florescent strips can be placed on book shelves or mounted inconspicuously to provide additional illumination. There are numerous types of lamps that screw into incandescent receptacles which can be used for lighting foliage plants.

Should the light intensity be too low, the new growth on the plant will become spindly and the new leaves will shrink as the plant develops.

On split-leaf philodendron, the new leaves not only become smaller, they no longer split.

At intensities less than 25 footcandles, most plants quickly degenerate. Levels of at least 50 footcandles are suggested when using artificial light as the sole source of illumination.

Improper watering is the other most important cause of failure with house plants. To determine when the soil is ready for watering is the key to success.

The soil should be allowed to get rather dry at the surface and this is particularly true with the large containers (9 inches or more) because the roots are down in the lower region of the pot. When the soil is dry at the surface it may still be moist enough for roots to grow satisfactorily. Soil dries more rapidly in a clay pot than in one of plastic or metal, and the soil in the lower regions of the container is the last to dry out. If the soil is not dusty dry at the top when water is applied, there will be too much moisture in the soil in the lower regions, the roots will be deprived of oxygen and severely damaged or killed.

When the plant is watered, use room temperature water. Apply water until it comes out through the drainage holes at the bottom. Wait 15 minutes for excess water to drain and empty the saucer. If the pot stands in water too long, roots may be damaged.

If there is no drainage hole, it is hard to tell how much water to apply. In general, a pot that holds one quart of soil will probably require one-half pint of water to adequately moisten all of it without causing an accumulation of water at the bottom of the container.

If the container lends itself to such treatment, the plant can be watered and then, after about 5 minutes, turned on its side so that excess water can drain out.

The terms over-watering and under-watering are rather meaningless unless defined. For example, if the soil is watered too often it can be considered over-watered, but if only a small amount of water is applied the soil may be wet on top but dusty dry below where the roots are.

When the soil is kept too wet the roots will be damaged and the upper leaves on most plants turn light green or yellowish. Once the roots die, the entire plant will wither. Nursing a plant in such condition back to good health is a dubious proposition and even if it can be done it will take a long, long time.

Generally, plants do not need to be watered as often during the short days of winter.