Houseplants and Indoor Air Quality
Houseplants and Indoor Air Quality
Houseplants can be the source of cleaner air, but they canalso be the exact opposite.
There are two main concerns with indoor plants, insects, andVOC's.
Insects? Yes. Any houseplant that does not thrive willeventually get infested with insects, especially mealy bugs,aphids, whiteflies, scale, or spider mites. All of these insectscan quickly explode in numbers and can present a serious allergyproblem. Insects shed old skin and other parts and this insectdander is very allergenic.
Insects also produce large amounts of feces, called "honeydew,"and on this rich organic material mold quickly grows. The moldthen produces reproductive mold spores, and these spores becomeairborne inside the house. Mold spores are of course quiteallergenic.
The answer to insects is to keep them healthy. First we shouldonly use houseplants that are well adapted to actually growinginside the house. These plants should get the kind of light theyneed. Plants that do not get the light they need will get buggy.We must also see to it that our houseplants are well fertilized.Lack of fertilizer will eventually result in a plant that isweak and that will then be attacked by insect pests. I liketime-release fertilizers for all houseplants. In addition totime-release fertilizers I also like to use some water-solublefertilizers too, at least once a month.
Houseplants should be kept clean too. Often dust will land andstick on the leaves and unless they are washed clean on aregular basis, houseplants can be regular dust piles. It isalways a good idea to wipe down the leaves of houseplants withsome clean water and a sponge. It is a good idea to add a tinybit of dish soap to the water when you wipe them down, ateaspoon to a gallon. Use lukewarm water. The soap will helpmake the leaves cleaner, and it discourages insects.
If you find insects on a houseplant, take it outside, put it inthe shade, and spray it thoroughly with a mix of dish soap andvegetable oil. Use several tablespoons of each to a gallon ofwarm water. Spray the plants, soak them every day for a week andif this doesn't get rid of the bugs, then consider dumping them.If the plants are valuable or you just can't bear to part withthem, add some neem oil to the above insecticide mix and spraythem with this several times.
Sometimes to kill scale on a plant I will pour some vegetableoil in a cup and then just brush it on the scale with a smallpaintbrush. In very few cases does the oil damage the leaves ofthe plants, and it will smother the scale. This also will workwith mealy bugs.
Do not bring buggy plants back into the house!
Even after you get rid of the pests on the plant, before youreturn it to your house you need to ask why was it that it gotbuggy in the first place? Is the light too weak? Is the air inthe house too dry for it? Have you been neglecting to feed itenough? Has it been kept too dry? Too wet? Is it too coldinside? Too hot? Whatever the answer, you'll need to changesomething in order to get it to thrive.
Make a habit of looking over the leaves and stems of all yourhouseplants on a regular basis. Look on the stems for scale.Look under the leaves for other insect or mite pests. Spidermites thrive in hot weather. Whiteflies thrive in cool weather.One of the best ways to control spider mites is to frequentlywash down the plants.
Dander from spider mites is especially allergenic and any plantthat continues to get infested with mites ought to be tossed.
VOC's and houseplants?
All plants release volatile organic compounds into the air.Often these are described as "biogenic emissions." Some plantsrelease only a small amount and consume much more than theyrelease. The ones to worry about are the plants that releasemore than they consume. Chiefs among the plant-produced VOCpollutants are carbon monoxide and ozone. Both of these areprimary elements of smog. They're not something you would wantin your house. Other VOC gases often of allergy concern insidehouses (but not necessarily produced by plants) areformaldehyde, benzene, xylene, toluene, ammonia, acetone, methylalcohol, ethyl acetate, and trichlorethylene.
Ficus trees. Ficus enjoy a good rating in the OPALS scalebecause they release so little airborne pollen. Unfortunately,Ficus, and especially the common houseplant tree, Ficusbenjamina, they are high emitters of VOC's. Does this mean weshould not use Ficus benjamina as a houseplant?
Yes, that's exactly what it means. At any rate, these oftenfail to thrive in houses since most household light is too weakfor them and most household air is too dry. They will often beinfested with spider mites or other insects and these will justadd to the VOC problem. VOC's are not good for people withallergies and will aggravate existing allergies. Actually, VOC'sare not good for anyone.
Which plants are VOC consumers?
Some years ago NASA scientists discovered that certain plantscan remove volatile organic compounds (VOC's) from the air. Thegases studied included formaldehyde, benzene, xylene, toluene,ammonia, acetone, methyl alcohol, ethyl acetate, andtrichlorethylene. The plants listed below are said to be quiteeffective at removing indoor pollutants. Please keep in mindthough that they must be growing healthy and they must be keptbug free in order to work. : Dracaena, Golden Pothos, RedEmerald Philodendron, Dumb Cane, Schefflera, Wax Begonia, SnakePlant, Norfolk Island Pine, Dracaena, Dendrobium andPhalaenopsis orchids, Spider Plant, Arrowhead Plant (Syngonium),Dwarf Banana (Musa), and Chinese Evergreen (Aglaonema) Alsorecommended for cleaning indoor air were Rhapis, Chamaedorea andPhoenix Palms, but it is important to note here that only femalepalms should be used. You don't need extra palm pollen in thehouse. In addition, also recommended for cleaning indoor airwere potted chrysanthemums and Gerbera Daisy, but I do NOTrecommend these as houseplants. They have high lightrequirements and will not thrive in most houses, and they cancause contact skin rash. Their pollen (they're ragweedrelatives) is highly allergenic. Better to keep the mums andGerbera daisies outside.
Also NASA recommended as an effective air cleaner plants wasPeace Lily, or Spathe Flower, but I do NOT recommend these ashouseplants either. They also can cause skin rash and when inbloom they too shed pollen that is allergenic.
It is always a good idea to let houseplants dry out a little bitbetween watering. This gives the roots a chance to get more airand it also discourages the growth of molds in the soil. Whenyou do water houseplants it is wise to soak them thoroughlyrather than give them just a little bit of water each time.Always use water that is luke- warm, at least at roomtemperature.
Houseplants can be the source of cleaner air, but they canalso be the exact opposite.
There are two main concerns with indoor plants, insects, andVOC's.
Insects? Yes. Any houseplant that does not thrive willeventually get infested with insects, especially mealy bugs,aphids, whiteflies, scale, or spider mites. All of these insectscan quickly explode in numbers and can present a serious allergyproblem. Insects shed old skin and other parts and this insectdander is very allergenic.
Insects also produce large amounts of feces, called "honeydew,"and on this rich organic material mold quickly grows. The moldthen produces reproductive mold spores, and these spores becomeairborne inside the house. Mold spores are of course quiteallergenic.
The answer to insects is to keep them healthy. First we shouldonly use houseplants that are well adapted to actually growinginside the house. These plants should get the kind of light theyneed. Plants that do not get the light they need will get buggy.We must also see to it that our houseplants are well fertilized.Lack of fertilizer will eventually result in a plant that isweak and that will then be attacked by insect pests. I liketime-release fertilizers for all houseplants. In addition totime-release fertilizers I also like to use some water-solublefertilizers too, at least once a month.
Houseplants should be kept clean too. Often dust will land andstick on the leaves and unless they are washed clean on aregular basis, houseplants can be regular dust piles. It isalways a good idea to wipe down the leaves of houseplants withsome clean water and a sponge. It is a good idea to add a tinybit of dish soap to the water when you wipe them down, ateaspoon to a gallon. Use lukewarm water. The soap will helpmake the leaves cleaner, and it discourages insects.
If you find insects on a houseplant, take it outside, put it inthe shade, and spray it thoroughly with a mix of dish soap andvegetable oil. Use several tablespoons of each to a gallon ofwarm water. Spray the plants, soak them every day for a week andif this doesn't get rid of the bugs, then consider dumping them.If the plants are valuable or you just can't bear to part withthem, add some neem oil to the above insecticide mix and spraythem with this several times.
Sometimes to kill scale on a plant I will pour some vegetableoil in a cup and then just brush it on the scale with a smallpaintbrush. In very few cases does the oil damage the leaves ofthe plants, and it will smother the scale. This also will workwith mealy bugs.
Do not bring buggy plants back into the house!
Even after you get rid of the pests on the plant, before youreturn it to your house you need to ask why was it that it gotbuggy in the first place? Is the light too weak? Is the air inthe house too dry for it? Have you been neglecting to feed itenough? Has it been kept too dry? Too wet? Is it too coldinside? Too hot? Whatever the answer, you'll need to changesomething in order to get it to thrive.
Make a habit of looking over the leaves and stems of all yourhouseplants on a regular basis. Look on the stems for scale.Look under the leaves for other insect or mite pests. Spidermites thrive in hot weather. Whiteflies thrive in cool weather.One of the best ways to control spider mites is to frequentlywash down the plants.
Dander from spider mites is especially allergenic and any plantthat continues to get infested with mites ought to be tossed.
VOC's and houseplants?
All plants release volatile organic compounds into the air.Often these are described as "biogenic emissions." Some plantsrelease only a small amount and consume much more than theyrelease. The ones to worry about are the plants that releasemore than they consume. Chiefs among the plant-produced VOCpollutants are carbon monoxide and ozone. Both of these areprimary elements of smog. They're not something you would wantin your house. Other VOC gases often of allergy concern insidehouses (but not necessarily produced by plants) areformaldehyde, benzene, xylene, toluene, ammonia, acetone, methylalcohol, ethyl acetate, and trichlorethylene.
Ficus trees. Ficus enjoy a good rating in the OPALS scalebecause they release so little airborne pollen. Unfortunately,Ficus, and especially the common houseplant tree, Ficusbenjamina, they are high emitters of VOC's. Does this mean weshould not use Ficus benjamina as a houseplant?
Yes, that's exactly what it means. At any rate, these oftenfail to thrive in houses since most household light is too weakfor them and most household air is too dry. They will often beinfested with spider mites or other insects and these will justadd to the VOC problem. VOC's are not good for people withallergies and will aggravate existing allergies. Actually, VOC'sare not good for anyone.
Which plants are VOC consumers?
Some years ago NASA scientists discovered that certain plantscan remove volatile organic compounds (VOC's) from the air. Thegases studied included formaldehyde, benzene, xylene, toluene,ammonia, acetone, methyl alcohol, ethyl acetate, andtrichlorethylene. The plants listed below are said to be quiteeffective at removing indoor pollutants. Please keep in mindthough that they must be growing healthy and they must be keptbug free in order to work. : Dracaena, Golden Pothos, RedEmerald Philodendron, Dumb Cane, Schefflera, Wax Begonia, SnakePlant, Norfolk Island Pine, Dracaena, Dendrobium andPhalaenopsis orchids, Spider Plant, Arrowhead Plant (Syngonium),Dwarf Banana (Musa), and Chinese Evergreen (Aglaonema) Alsorecommended for cleaning indoor air were Rhapis, Chamaedorea andPhoenix Palms, but it is important to note here that only femalepalms should be used. You don't need extra palm pollen in thehouse. In addition, also recommended for cleaning indoor airwere potted chrysanthemums and Gerbera Daisy, but I do NOTrecommend these as houseplants. They have high lightrequirements and will not thrive in most houses, and they cancause contact skin rash. Their pollen (they're ragweedrelatives) is highly allergenic. Better to keep the mums andGerbera daisies outside.
Also NASA recommended as an effective air cleaner plants wasPeace Lily, or Spathe Flower, but I do NOT recommend these ashouseplants either. They also can cause skin rash and when inbloom they too shed pollen that is allergenic.
It is always a good idea to let houseplants dry out a little bitbetween watering. This gives the roots a chance to get more airand it also discourages the growth of molds in the soil. Whenyou do water houseplants it is wise to soak them thoroughlyrather than give them just a little bit of water each time.Always use water that is luke- warm, at least at roomtemperature.