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In the Garden: What do houseplants need to survive?

By Scott Eckert
Special to The Newton Kansan
Houseplants need light and the right amount of water to be successful.

What do houseplants in Kansas need to survive in the wintertime? We know if we have them outside in the winter they will freeze and die. So how do we care for and keep them alive?

Scott Eckert

Very few plants tolerate dark corners. Most houseplants require the light that would be found within 4 to 8 feet of a bright south window. Some will tolerate a spot very near the window, while others will prefer less light some distance away. Too little light can result in tall, lanky, small-leafed plants. Too much light can cause leaf burn on sensitive species like African Violet. Drapes should be left open during the day where houseplants are being grown. However, be careful not to allow the plants’ leaves to touch the glass of the window.

If the room is not naturally lit, artificial lights should be used. A 100-watt table lamp can be used about 3 feet above plants. Specially built fluorescent plant lights are available. Either fluorescent or incandescent plant lights are satisfactory for growth.

Avoid placing plants in hot spots or cold drafts. Almost none will survive the hot, dry air from a furnace vent, nor like being placed near a door where cold drafts enter.

Most houseplants prosper in a temperature of 65 to 75 degrees, but the humidity of the average home is too low to suit them. A plant prospers in relative humidity of about 50% to 60%, which is more than most people like.

This can be helped by using a humidifier or by setting the pot on a tray of moist gravel or pebbles. Do not allow the water to touch the bottom of the pot, as the water would then be wicked into the potting medium and keep the plant too wet. A transparent polyethylene bag can be draped over the top of plants that are extremely sensitive to humidity or are in poor condition.

More houseplants succumb from improper watering than from any other single cause. In general, most houseplants need to be thoroughly watered and then allowed to nearly dry before the next irrigation. Use tepid water when watering houseplants. Enough water needs to be poured over the potting medium to allow water to drain freely through the drain hole at every watering. If water does not drain out the bottom, re-water until it drains freely. Never leave a houseplant standing in water, as this will cause the roots to rot.

Generally, plants are watered when the potting medium becomes dry to the touch. However, some plants, such as African violet and Rex begonia, need to be watered before the potting medium becomes completely dry to the touch. Cacti and other succulents need to be allowed to remain dry a few days before watering, even though the top of the potting medium may be dry to the touch.

Watering frequency depends on the potting medium used, season, amount of light, temperature, humidity, plant species, and pot size. Small pots are more difficult to manage in the home than larger pots, since they dry more rapidly, and water does not move as uniformly through the potting medium. Small pots may require watering every two to three days, while large pots may not need watering more than every seven to 14 days.

— Scott Eckert is a Kansas State Research and Extension agent for Harvey County. Horticulture is his specialty. He can be reached at 316-284-6930.