Eight Common Indoor Plant Myths

Over the years a number of ideas have come to be accepted as part of the conventional wisdom of plant care. Some of these ideas started with nursery growers who developed their plant care techniques based on the optimal conditions that they can create in their greenhouses and nurseries. Unfortunately, some of these practices are inappropriate for houseplant owners growing plants in more trying circumstances. No wonder so many people believe they just don’t have green thumbs.

Myth #1: Plants grow bigger in bigger pots

Fact: The fastest growing plants are those that are moderately potbound. Frequently repotted plants put much of their energy into growing more roots, at the expense of leaves and flowers. Plants in large pots are also much more likely to suffer from root rot.

Myth #2: Ailing plants will benefit from plant food

Fact: Plant food or fertilizer is not medicine. It is intended for healthy plants that are growing vigorously and are using up the essential nutrients in the soil. You cannot force plants to use more nutrients than they need. Excess nutrients accumulate in the soil and burn tender roots and cause leaf discoloration. Ailing plants absorb fewer nutrients than healthy plants.

Myth #3: Indoor plants need lots of direct sunlight

Fact: Only some indoor plants benefit from direct sun. Many common indoor plants are shade-lovers that suffer from” sunburn” when exposed to the direct rays of the sun.

Myth #4: Yellow leaves and brown tips mean over watering

Fact: These common symptoms have many possible causes including too little water, inadequate light, excess fertilizer, fluoridated water, hard water, and poor soil quality.

Myth #5: Misting plants will increase the humidity for plants

Fact: Misting plants once or twice per day increases the humidity by so little that it has no practical value for humidity-loving plants. Misting does help keep plants clean, however.

Myth #6: Most indoor plants need high humidity to thrive.

Fact: Most of the commonly available indoor plants are commonly available because they have proven their ability to adapt to the very dry environments found indoors in winter. Although most indoor plants, succulents excepted, come from naturally humid habitats, many can survive quite well in low humidity, as long as they receive adequate moisture through their roots.

Myth #7: Chemical pesticides are the only effective way to eliminate plant pests.

Fact: There are many safe and effective treatments for plant pests. These treatments include such safe products as dish soap, rubbing alcohol, horticultural oils, silicon, sand, sticky traps, diatomaceous earth, and hot pepper.

Myth #8: Most indoor plants go dormant in the winter.

Fact: Most indoor plants come from tropical regions that are warm year-round. Unlike temperate zone plants, tropical plants grow actively all year long. Indoors in northern climates the winter months bring shorter hours of daylight. This reduction in light will cause plant growth rates to slow leading some observers to believe they are dormant.



GPGB Supporters Help Prove the Science of Indoor Plants

Project Carbon, a recent research project completed at the University of Georgia, proves that plants do in fact remove carbon from the air we breathe. This study is the first of its kind to provide quantitative data of carbon removal by plants in an interiorscape setting.

According to Mike Lewis, President of Green Plants for Green Buildings, “GPGB has long been at the forefront in making the case that indoor plants provide a healthier environment as well as a happier community. We are grateful to our supporters for helping us bring to light the scientific evidence that augments the aesthetic appeal of our indoor ‘Air Cleaners.’”

Project Carbon, funded by the National Foliage Foundation (NFF) and supported by Green Plants for Green Buildings and the Florida Nursery, Growers and Landscape Association, allowed researchers, Dr. Bodie Pennisi and Dr. Marc van Iersel, to identify the amounts of carbon removed from the air by plants, both under simulated conditions and in actual interiorscape environments. A little over a year later, research proves there is an advantage to having plants in homes and offices.

Research Highlights:

  • In addition to absorbing carbon, plants improve indoor air quality by removing pollutants.
  • While all plants take carbon out of the air, larger, woody plants absorb and keep in their bodies more carbon than small herbaceous plants over time.
  • Plants must be in healthy condition to continue removing carbon from the air we breathe.

According to Linda Reindl, NFF Administrator, the research documented that interiorscape plants remove several volatile organic compounds (VOCs) such as benzene and formaldehyde. This aspect should serve as a basis for the claim for improvement of indoor air quality. Carbon dioxide assimilation provides corollary information to VOC removal and a more complete assessment of plants’ benefits to the indoor environment.

Technically speaking, Project Carbon was conducted in two phases. The first phase included growing plants under simulated interiorscape conditions. Plants were grown for 10 weeks and upon termination, the following data was taken: shoot and root dry weights and total leaf area. From this data, scientists calculated the amount of carbon that interiorscape plants removed from air. The second phase consisted of measuring carbon removed by plants “on the job” — that is plants installed in an actual interiorscape.

“GPGB is here to give interiorscape professionals the tools to show the public that they can provide the best conditions for a healthy interior environment. The fact that research proves indoor plants must be healthy in order to clean the air has far reaching implications for those of us responsible for their care,” said Lewis.

For more information on this and other research projects supported by GPGB, visit www.greenplantsforgreenbuildings.org. For details directly related to Project Carbon, contact Dr. Bodie Pennisi at the University of Georgia.

Earth Day: Greening Your Office Space


Want to be more eco-friendly at work?  Here’s our favorite tips for greening your office space:


A plant for every office.  Did you know that the ordinary office plant can rid the air of harmful toxins, improve your health and make you more productive?  It’s true and there are over 20 research studies to prove it.  You don’t need a jungle, the most recent research shows that one plant per 160 square feet of office space (about the size of an average office) is all you need, provided the plant is at least in an 8” growing pot (a large desk plant or small floor plant.)  You could also use 3 or more tabletop plants to get the same results. 


Bring in your own coffee cup.  You can cut down on the Styrofoam and plastic cups and bottles that fill our landfills by using your own cup.  Not practical?  Switch to recyclable paper cups instead.  Which brings us to our next tip:


Recycle!  Most urban areas and commercial buildings now have recycling programs, so set up those bins and get cracking.  Nearly 90% of all office waste can be recycled.


Use products made from recycled materials.  Recycled office paper is easy to find, as well as recycled paper towels, etc.  More products are being made from recycled products so keep your eyes opened.  Look for products with a high amount of post-consumer recycled material.


Open the blinds and turn off the overhead lights.  If your office has windows, turn off your overhead lights and use natural daylighting instead.  Use task lighting at your desk if you need more light. You’ll save energy and enjoy the view!  Close the blinds over the weekend and at night to help moderate the temperature and cut down on energy use.


Own the building?  Use native plants and xeriscaping to cut down on irrigation water and grounds maintenance.  Your landscaping company will be glad to help you with a more eco-friendly design.  Set up a bird-friendly area with a water source and berry- or nut-producing plants while you’re at it.


Switch to fair trade coffee and tea.  Your favorite beverage can be grown in an eco-friendly manner, no matter what part of the globe it originates, and one in which local laborers are paid a fair wage for an honest day’s work.  Just what you’d want for your own family, right?


Kick the habit.  Smoking, that is.  Smoking releases all kinds of cancer-causing toxins into the air, let alone what it does to your own set of lungs.  You know it’s bad for you, but it’s also bad for everyone else in your office.  Besides, we know you’ve been wanting to quit, haven’t you?!


Bromeliads: A Splash of Color

Most of these plants from the “pineapple” family come from Central and South America where they grow as epiphytes on trees and rocks or on the rainforest floors. Among the genera most often used in the interiorscape are: Aechmea (“Living vase” or “Urn plant”); Billbergia (“Queen’s tears); Cryptanthus (“Earth stars”); Guzmania (“Torch plants”); Nidularium (“Birdsnest”); Tillandsia (“Silver birds”); and Vriesea (“Painted feathers”).


Bromeliads are hardy and very easy to care for. Once in bloom, they can sustain their flowers and colorful bracts for several weeks in low light, (though they prefer filtered or full sun), and can survive at chilly temperatures, (though they thrive in a warm room). Once the flower is spent, the plant can maintain it’s showy foliage for several months.


Bromeliads prefer around 40 to 60 percent humidity though for short term use in color rotation, they can tolerate a dry environment. Some light misting is helpful if they are in a warm room where the moisture will not damage the leaves or flowers.


Though bromeliads appear to be succulents they are not. They need regular watering and should not be watered in their cups unless they are in a very warm location in which the water will evaporate within the space of one day. Water them at soil level and do not overwater as they can rot, particularly if they are planted in soil as opposed to bark.

While growing them in the greenhouse, you can water them in their cups, though the water should not be allowed to sit for more than a day or two at most. This does not usually occur because there is sufficient heat to evaporate any excess. They also need to have their growing medium moistened, but they should not be allowed to stand in water. Feed them monthly with a water soluble complete plant food.


Most interiorscapers never see any one particular bromeliad for longer than about two to three months. By then the flower is spent and it’s in the dumpster for the whole lot. This is unfortunate since minimal greenhouse attention can produce a new lot within a year or two. Once a bromeliad has finished its season, it sends out off-shoots or “pups” which can be separated from the mother plant using a sharp, sterile blade. These pups can then be planted in a growing media, usually sphagnum peat though any light, porous material, such as Osmunda, will be satisfactory.

To force flowering, enclose a group of moist, not wet, mature plants within an airtight plastic covering and insert some ripening fruit (apples are easiest) inside with them. Do this in a warm greenhouse only. The ethylene that is emitted by the apples will cause the plants to flower. The process should take anywhere from three to seven days and should be closely monitored so that it isn’t overdone.

Plants Reduce Stress (no foolin’)

Respected research done by Dr. Roger S. Ulrich of Texas A&M University, Helen Russell, Surrey University, England as well as those conducted by Dr. Virginia Lohr of Washington State University verify that plants significantly lower workplace stress and enhance worker productivity. In Dr. Lohr’s study, common interior plants were used in a computer laboratory with 27 computer workstations. A computer program to test productivity and induce stress was specifically designed for these experiments. Participants working in an environment with plants present were 12 percent more productive and less stressed than those who worked in an environment without plants. 

Green Walls = Clean Air & Functional Style

We currently live in a world where little is untouched by man. Pollution reaches the farthest corners of the planet. It is almost enough to make you want to run inside and hide! However, this may not be the best idea because according to modern scientific research, indoor environments may be as much as ten times more polluted than the outdoor environment. This is known as “Sick Building Syndrome”.

The average person spends over 90% of their time indoors. We are constantly being bombarded with indoor air pollution. This includes toxic fumes such as formaldehyde, VOCs, trichloroethylene, carbon monoxide, benzene, toluene, xylene, and countless others.


The good news is that all plants absorb and clean pollutants from the air. Certain tropical species are more efficient than others. At Foliage Concepts we have hundreds of different plants at our disposal. We always make sure that each of our green walls contains ample numbers of the plants which are best at improving air quality. A single potted plant removes a portion of these airborne toxins and with each additional plant this increases. A green wall can contain over a thousand plants, all of which filter air and in addition create energy-rich oxygen. 


Below is more information about common indoor air toxins and how green walls help.

Formaldehyde (CH2O)

is found in products such as furniture, wall paper, cardboard, and facial tissues. It is also used in some plastics, paints, varnishes, dishwashing liquids, fabric softeners, and cosmetics, such as nail polish. It enters the indoor environment through natural sources such as forest fires and certain human activities, including burning tobacco, gasoline and wood. As a result of being in so many common products and so prevalent in the environment, it is present, in its breathable gas form, in virtually all homes and buildings. Studies have suggested that people who are exposed to low levels of formaldehyde for long periods of time are more likely to experience asthma-related respiratory symptoms, such as coughing and wheezing. In higher amounts formaldehyde is known to cause cancer of the nasal cavity.


or volatile organic compounds are found in all petroleum products; however there are many other sources such as flooring adhesives (used for carpeting, hardwoods, etc), paint, furniture, wall materials, electronic equipment, cigarette smoke, household cleaning products and even air fresheners! The main reason we should be worried about VOCs is because they are the primary precursor to the formation of ground level ozone and particulate matter in the atmosphere which are the main ingredients of the air pollutant referred to as smog. The negative health effects of smog are well documented.

 Trichloroethylene (TCE)

is a common indoor pollutant being released from paints, dry cleaning, adhesives, pesticides and the ink in copy machines, faxes, and printers. Short-term exposure to TCE causes irritation of the nose and throat and depression of the central nervous system. Higher concentrations have caused numbness and facial pain, reduced eyesight, unconsciousness, irregular heartbeat and even death.

 Carbon monoxide (CO)

is a dangerous gas which is produced from open fires, gas stoves, appliances and heaters. It is also present in high concentrations in cigarette smoke and vehicle exhaust. Low level exposure causes dizziness and headaches while more acute exposure can lead to death because CO actually prevents the delivery of oxygen to the body’s cells.

 Benzene (C6H6), Toluene (C7H8) and Xylene (C8H10)

are found in the vapour of products such as gasoline, oils, paints, glues, inks, plastics, and rubber, where they are used as solvents. These three pollutants also enter into the composition of detergents, explosives, pharmaceuticals, foams and dyes. They are skin and eye irritants and are known carcinogens, in connection to human leukemia.

According to the Environmental Protection Agency, “people living and working in buildings of manmade materials inhale over 300 contaminants every day.” Concerns about these contaminants arise from the hypothesis that, when combined, the toxicity of hundreds of different chemicals can “add up” to create major health hazards.


How Green Walls Can Help

So how does this all relate to green walls, you may ask. Well, research undertaken by the National Aeronautics and Space Administration (NASA) proves that plants are capable of cleaning indoor air of the toxic chemical soup that is common in modern buildings.

Dr. William Wolverton, NASA’s principal investigator researching air quality on space stations, stated that chemicals such as formaldehyde and carbon monoxide can be removed from indoor environments by the plant leaves alone. VOCs, TCE, benzene, toluene, xylene and numerous other toxic chemicals can be removed by the roots of plant (or by the microorganisms living around the roots which degrade and assimilate these chemicals).


The chart below lists toxic chemicals commonly found inside buildings and just a few examples of green wall plants which are the most efficient at absorbing and neutralizing them.

Common indoor toxic chemical
Green wall plants best at removing these toxins
Formaldehyde (CH2O) Peace lily (Spathiphyllum sp.)
Boston fern (Nephrolepis exaltata ‘Bostoniensis’)
English ivy (Hedera helix)
Carbon Monoxide (CO) Spider plant (Chlorophytum comosum)
Janet Craig Dracaena (Dracaena deremensis ‘Janet Craig’’)
Ficus sp.
Volatile Organic Compounds (VOCs) Golden Pothos (Scindapsus aures)
Devil’s ivy (Epipremnum aureum)
Philodendron sp.
Trichloroethylene (TCE) Mother-in-law’s tongue (Sansevieria trifasciata ‘Laurentii’)
Chrysanthemum (Chrysantheium morifolium)
Dracaena sp.
Benzene (C6H6) / Toluene (C7H8) / Xylene (C8H10) Kimberly Queen Fern (Nephrolepis obliterata)
Orchid sp. (Phalenopsis sp.)
Dieffenbachia sp.
Toxic chemicals and the tropical (green wall) plant species which are best at removing them. Adapted from Dr. B.C. Wolverton’s book – How to Grow Fresh Air, 1996.

Through the process of photosynthesis, plants take in carbon dioxide (CO2) and release oxygen (O2). An increase in oxygen helps to keep us awake and alert.


Another advantage of having a green wall is that it saves a lot of space. If the same number of plants that we use on our living walls were growing in pots on your floor you could probably fill your whole house! You will benefit from a dramatic increase in air filtration and oxygen production and do so using much less valuable floor space.

Gift Plant Program

Gift PlantFoliage Concepts has recently begun their new Gift Plant Program for building & property managers.  When a new tennant moves into one of their properties, the management company can call one of our three locations and we will deliver a gift plant to the tennant on behalf of the management company at no charge.  The plant will include a card complete with the management company’s color logo, welcoming the new tennant to the building.