Here’s some good news for those of you who have trouble growing houseplants: The problem could lie in where you put the plants rather than in your being short a couple of gardening genes. Light, temperature and humidity have a lot to do with whether a plant thrives or dies.
We’ll help you choose the right plants for your home, and then help you find the proper location and care for them.
Right Plant, Right Place
Light levels, humidity and temperature vary throughout every home. Match plants to specific conditions.
Light. “Light is clearly the most limiting factor to growing plants indoors,” says Deborah Brown, University of Minnesota extension horticulturist. “All plants need light to manufacture food, but the amount needed varies from one plant to another.” Most houseplants thrive in moderate to bright, indirect light. Flowering plants and those with colored leaves usually need higher light levels than plants with green leaves. And a select group of plants, including the popular Chinese evergreen and cast-iron plant, will tolerate very low light levels.
Plants show signs of stress when light levels are too low or too high. Weak, spindly growth indicates insufficient light. Variegated foliage will lose all or part of its markings. Signs of too much light are bleached or wilting leaves on plants like scheffleras, philodendrons, ferns and peperomias. Quick foliage drop, most dramatic on figs (Ficus species), can result from a sudden move from bright light to low.
Even when you find what seems to be the ideal spot for your plants, it might be necessary to move the plant as the seasons—and light levels—change. Plants that thrive in the direct sun of a south- or west-facing window in winter might sunburn if left in the same spot in late spring or summer as light intensifies. In this case, move plants farther from the glass or filter light with a sheer curtain.
Humidity. Most houseplants originate in tropical or semitropical regions, where the air is moist. Many of these plants can adapt to the drier air in our homes, but they do better when humidity is increased?especially during winter when most homes are heated. With insufficient humidity, leaves turn dull and papery. Brown leaf tips are another common symptom.
“One solution is to locate plants that need more humid air, such as ferns, in the kitchen or bathroom, where humidity tends to be highest,” says Matthew Gardner, owner of The Wright Gardner, a San Francisco-based interior-plantscape company. Another option is to place a humidifier in the room where most of your plants are located.
There are several other ways to raise the humidity around plants. Grouping plants keeps the moisture level higher than if air freely circulates around each plant. Another way is is to place plants on a shallow waterproof tray of pebbles partially covered with water. The pebbles provide lots of extra surface area for evaporation. (But don’t let the plants sit in the water, or roots could rot.)
Many people mist plants to raise the humidity level, but it’s not effective. The water evaporates too fast to benefit plants.
Temperature. Houseplants are “houseplants” because they need the same conditions we do to survive. Most like daytime temperatures ranging from the upper 60s° to the mid-70s°F, and nights that are about 10°F cooler.
But be aware of cold or hot spots. For example, on extremely cold winter nights, temperatures on a windowsill could be considerably lower than elsewhere in the room. Tender plants can freeze unless you protect them. Keep foliage from touching windows and provide protection with a heavy curtain, or place a piece of cardboard between the glass and the plants.
Few plants tolerate cold drafts or hot air blowing on them. So, don’t place plants next to an exterior door or heating duct.
Once plants have settled into your home, attention to watering and a few other routine jobs keep them in good shape.
Watering. The one word to describe how to water is thoroughly. Use tepid water and supply enough so excess flows through the soil and out from the drainage hole in the bottom of the pot. But don’t let the plant stand in water collected in the drip saucer for more than a few minutes. Instead, dump the water from the saucer, or if the saucer is large and awkward to maneuver, use a turkey baster to suck up water from the saucer.
How frequently you water depends on the plant and conditions in your home, including temperature and humidity. Some plants, notably ferns, do best when the soil is kept evenly moist. For other plants, such as cacti and succulents, the soil should dry thoroughly between waterings. But most houseplants fall in a third category: They do best when the soil dries slightly between waterings. With these plants, allow the soil to dry 1/2 to 2 in. below the surface before watering again. Precision is impossible here; the specific plant and the size of the container have a significant bearing on timing. Often you can tell when a plant is thirsty?the leaves lose their sheen just before they wilt.
Fertilizing. “Fertilizing falls into the less-is-more category,” explains Gardner. He says people have a tendency to overfertilize plants. But too much fertilizer does more harm than good. After all, plants make their own “food,” with the help of the sun. Fertilizer primarily promotes growth.
Use a fertilizer labeled for houseplants, and apply it at half strength, suggests Gardner. As a guideline, fertilize regularly in spring and summer, when plants are actively growing and can make most use of the added nutrients. Cut back in fall, when growth slows, and stop fertilizing once daylight-savings time ends. And, to prevent root burn, make sure to always moisten the soil before adding fertilizer.
Grooming. Dusting leaves does more than show off plants. “Dust buildup encourages insects, and it also filters the light that reaches leaves,” says Brown. Especially in winter in northern climates, plants need all the light they can get to manufacture food. “Wash leaves individually with a soft cloth moistened with tepid water,” Gardner advises. (Clean plants with feltlike leaves, such as African violets, by dusting them with a small, soft artist’s paintbrush.)
Do not use commercial leaf-shine products because they create a sticky surface that collects more dust and dirt. Also, “They make the leaves appear too shiny and unnatural,” Gardner says.
While you’re grooming, check for insects. Mealybugs that appear as white cottony spots are apt to be your worst problem. Use insecticidal soap or, if that’s not handy, daub each bug with a cotton swab dipped in rubbing alcohol. Rinse with tepid water. This same technique also works on other immobile plant pests, such as scale insects.
Spider mites, another common houseplant pest, spin fine webs on the underside of leaves. Spray them with insecticidal soap. It may take repeated applications to eliminate them.
Remember, start with plants that fit with the conditions in your home, and then provide commonsense care. Don’t push your plants to grow, just enjoy them. Oh, and check your thumb?it just turned green.
Pairing Plants With Light
Use this guide to match plants to locations in your home. You might want to make a copy to keep in your wallet. Then the next time you plan to buy a plant, you’ll be ready.
Direct light. These plants thrive on or near windowsills facing east or west that receive at least a few hours of direct sun during the day. Or, place them no more than a couple of feet away from a south-facing window.
Croton (Codiaeum variegatum pictum)
Jade plant (Crassula arborescens)
Medicine plant (Aloe barbadenensis)
Ponytail palm (Nolina recurvata or Beaucarnia recurvata)
Bright indirect light. For these plants, choose locations that receive as much light as possible without any direct sun, such as a few feet from a south- or west-facing window, or closer if protected by sheer curtains.
Bamboo palm (Chamadeorea seifrizii)
Fishtail palm (Caryota mitis)
Golden pothos (Epipremnum aureum)
Grape ivy (Cissus rhombifolia)
Lady palm (Rhapis excelsa)
Rubber tree (Ficus elastica)
Spotted dumb cane (Diffenbachia maculata)
Umbrella plant, or schefflera (Brassaia actinophylla ?Arboricola’)
Weeping fig (Ficus benjamina)
Low light. These plants tolerate low-light locations near a north-facing window or the interior of a bright room, away from windows.
Cast-iron plant (Aspidistra elatior)
Chinese evergreen (Aglaonema commutatum)
Dracaena (Dracaena species and varieties)
Kentia palm (Howeia species)
Parlor palm (Chamaedorea elegans, also sold as Neanthe bella)
Snake plant (Sansevieria trifasciata)
Plants With Style
The following tips from Matthew Gardner, owner of The Wright Gardner, an interior plantscape company in San Francisco, will help you match plants with your decor.
Traditional home furnished with antiques:
Contemporary house with lots of glass:
Madagascar dragontree (Dracaena marginata)
Country home with casual furnishings:
4 Ways to Kill a Houseplant
Most houseplants are resilient, but there are common mistakes that will do in even the most reliable types:
1. Transport the new plant from the nursery to your home in the trunk of your car on a cold winter day.
Many houseplants are seriously damaged if the temperature drops much below 50°F. To protect a plant, place it in a cardboard box and close the lid, or wrap it in newspaper or paper bags. Then place it on the front seat of a heated car.
2. Allow the pot to sit in water collected in the drip saucer.
This results in high concentrations of soluble salts in the soil. An excess of salt weakens a plant and makes it more susceptible to attack from insects and disease.
3. Repot the plant in garden soil.
Garden soil hardens when stuffed
into a pot. The result is poor drainage and lack of oxygen, a houseplant death sentence. Always use high-quality packaged potting mix labeled for houseplants.
4. Plant in a container with no drainage hole.
Sooner or later, the plant will suffocate. If you have a favorite decorative pot that lacks a drainage hole, plant in a smaller pot that drains and place it in the non-draining pot.
What should you do if a plant just doesn’t work out because, for example, the cat relentlessly chews on the leaves, it’s too messy or it’s plagued by aphids? Toss your troubled plant on the compost heap or throw it away, then treat yourself to a replacement.