Easy-to-Grow Houseplants that Keep Indoor Air Clean

For at least three decades, NASA has been doing strictly controlled studies of plants' abilities to purify air. Initiated for space station systems, the information from these closed-system studies also applies to today's super-sealed and insulated homes. Cutting drafts and air leaks, and sealing heated and cooled air inside may reduce your energy usage, but it creates poor indoor air quality. A sealed house traps chemicals such as formaldehyde that are constantly given off by building materials and furnishings, and it can trap radon and carbon monoxide as well. The contaminated sealed air causes respiratory illnesses and has been linked to other health problems. Sick Building Syndrome and Sick Home Syndrome are terms coined to describe this type of poor-quality indoor air.

But there is a simple remedy.

Common houseplants continuously filter the air. Contaminants in the air are absorbed by the plants and "processed" until the residues are deposited into the potting soil through the roots. Microbes in the soil continue to break down contaminates until they are reduced to their organic beginnings. Pretty cool cycle!

For your houseplants to purify effectively, skip the new "soil-less" growing medium and use REAL potting soil. Organic soil or compost is best. You need those microbes.

The following houseplants have been identified as some of the best air purifiers. For the best air purification, use about 15 plants in a 2,000 sq ft home. Each plant should be in a 6 inch pot or larger. Fewer, larger plants will do the same purification job. For example, a 4-foot tall ficus would equal about four 6-inch pot plants. (See image above.)

The plants listed all have low to medium light requirements, so they will grow in natural light in almost any room of your home, or with plant lights if you want to purify the air in a finished basement. If your windows are made of any of the e-glass types that filter the sun's rays, even your bright, south-facing windows have LOW light.

The plants on the list need modest to infrequent watering. This means that watering once a week or so is fine, and they won't suffer (much) if you are a couple of days late watering them. Remember that dry leaf edges/tips are a sign of low humidity, not inadequate watering. If you don't have a humidifier, you can simply mist the leaves daily to increase the humidity.

1. Philodendron scandens `oxycardium', heartleaf philodendron
2. Philodendron domesticum, elephant ear philodendron
3. Dracaena fragrans `Massangeana', cornstalk dracaena
4. Hedera helix, English ivy
5. Chlorophytum comosum, spider plant
6. Dracaena deremensis `Janet Craig', Janet Craig dracaena
7. Dracaena deremensis `Warneckii', Warneck dracaena
8. Ficus benjamina, weeping fig
9. Epipiremnum aureum, golden pothos
10. Spathiphyllum `Mauna Loa', peace lily
11. Philodendron selloum, selloum philodendron
12. Aglaonema modestum, Chinese evergreen
13. Chamaedorea sefritzii, bamboo or reed palm
14. Sansevieria trifasciata, snake plant
15. Dracaena marginata , red-edged dracaena

Resources:
http://ntrs.nasa.gov/archive/nasa/casi.ntrs.nasa.gov/19860066312_1986066312.pdf
Personal experience