Growing in the great indoors
It's hot, dark, drafty -- now what plant can survive that?
Many of the plants we like to grow indoors hail from tropical, subtropical or desert lands where they evolved to need more light and much better drainage than they typically get in a Chicago living room. A plant that comes from a moist rain forest can have a hard time in the dry air of a centrally heated apartment.So how can you help plants survive in your home? "The best way to have success with a houseplant is to do a little bit of research and find out where the plant came from, and try to emulate those conditions," says Scott Wenthe, manager of horticulture at the Peggy Notebaert Nature Museum in Chicago.
In Chicago, you would need similar conditions: Bright filtered light, high humidity, steady warm temperatures, watering that never leaves your roots submerged and excellent air circulation.
It's easier to choose a plant that will do well in your home's environment than to try to change your conditions to suit a picky plant. Here are some things to think about as you assess your home's plant habitat:
Light: It's the foremost need of any plant. How much you can offer depends largely on which way each window faces. A south window offers bright light; a north window, low light; east and west windows, part light. Still, "plants that are on a windowsill receive a fraction of the light that is available outdoors," Wenthe says.
Plants have different light needs. Blooming takes a lot of energy, so flowering plants need more light. Many foliage plants have become favorite houseplants because they can get along with less.
Most cacti and succulents hail from bare, arid areas and need the full sun of a south window, says Steven Meyer, horticulturist at the Lincoln Park Conservatory in Chicago.
Water: The No. 1 reason for houseplant death is overwatering, Izenstark says. Plants can drown if their roots are swamped and can't get the air they need.
Different plants need different amounts of water, so "don't water your plants on a regular schedule. Water them when they need it," Meyer says. For most plants, that means water when the soil is dry to the touch.
Let the water soak through the soil, and then drain it out of the saucer. And "don't water houseplants with cold water; it will shock them," Meyer says.
Soil: It's best to use sterile potting mix, which drains well and has no risk of transmitting disease. It has few nutrients, though, so plants must be fertilized when they are not dormant.
Fertilizer: Plants in pots need the nutrients provided by a good all-purpose houseplant fertilizer, but they can be overstimulated by too much fertilizer, especially in winter.
In nature, plants go into a period of dormancy in winter. "There are fewer hours of daylight. The plant's growth slows," Meyer says. "So you should slow down on water and fertilizer."
Resume regular fertilizing, at half the strength suggested on the label, in midspring.
Temperature: Most houseplants will do well in the range of temperatures people like, Wenthe says. Just be sure to protect them from drafts or from sudden changes in temperature. Some plants, such as Ficus benjamina (a tree native to southeast Asia), will drop their leaves when stressed by sudden temperature changes.
Humidity: The colder air is, the less humidity it holds. In the winter, we take dry, cold outdoor air and heat it in our homes. Succulents, such as aloe vera (native to northern Africa), are suited to this dry air, says Laury Lewis, a Master Gardener who coordinates houseplant classes for the Chicago Public Library's Blooming Branches talks and who grows many houseplants in his Lincoln Park townhouse.
Houseplants that come from rain forests do better with a humidity boost. An evaporative humidifier works well. You also can create a zone of higher humidity by placing plants on a tray of pea gravel filled with water, Meyer says.
Gathering your houseplants into one area also helps; they give off water through their leaves, so a group creates a zone of higher humidity, Meyer says.