Less than a month to show time!  “Canada Blooms”, the Toronto flower and garden extravaganza, will open its doors at the Metro Convention Centre, next to the CN Tower, on Wednesday, 22 March 1999 at 10 a.m.  When it closes five days later at 6 p.m. 26 March, 100,000 people will have visited.  Tickets are $10 in advance (416) 447-8655 or $15.00 at the door.  It is rated as one of the top five of such shows in North America.  Acres of gardens, competitions for amateurs and professionals, a market place, talks and demonstrations all await gardeners suffering severely from cabin fever.

“Everybody believes plants are the answer to sick buildings and indoor air pollution.  It’s one of the great urban myths,” says Peter Dingle, an environmental scientist from Murdoch University in Western Australia.  A most interesting account of his recent  research into the effects of houseplants on indoor pollution was published in the New Scientist magazine.  (January 15, 2000; No.2221)

Professor Dingle examined office buildings in Perth, Western Australia, where his university is located, as well as several “temporary” structures on the campus.  Do plants reduce the effects of “Sick Building Syndrome (SBS) that have been widely reported from the industrialized world?  Basically, this is a vague but definite malaise, but without any other discernable cause than the atmosphere of modern office buildings in which the sufferers work.

It is recognized that many modern furnishings and construction materials, especially plywood and pressed wood products, emit miniscule amounts of formaldehyde.  This obnoxious chemical can cause irritation to the skin, throat, and eyes, increase asthma symptoms and become a carcinogen.  Dingle and his colleagues claim that very large numbers of plants, 20 in 8 square metres, will reduce formaldehyde levels down from 856 parts per billion (ppb) to 761 ppb.  The world health Organization recommends that levels not exceed 82 ppb.  Perth offices ranged from 10 – 78 ppb and the university structures a staggering 420 – 2110 ppb.  His conclusion?  “They really make a place more comfortable and beautiful, but they do not clean the air of pollutants to any significant degree.”

Strangely, no mention is made of a far more extensive study by Dr. Bill C. Wolverton of the National Aeronautics and Space Administration’s stennis Space Centre in Massachusetts, presented at the National Foliage Foundation’s Interior-scape Seminar, July 19, 1988 in Florida.  He showed that formaldehyde was in fact reduced from 20 ppm down to 3 ppm by a specimen of Philodendron domesticum.  Many other plants were tested and found to be of varying efficiency.  One of the most effective was Chlorophytum, the popular Spider Plant.  NASA’s tests at that point had been gong on for 15 years.  Research included more than formaldehyde, which is but one possible contaminant of offices.

The initial findings have been extended by further research, pointing toward the same conclusion. Indoor plants reduce the pollutants that cause SBS.  Of course in the home, we have the option of opening the door and allowing in some of that deliciously fresh Toronto air to replace those chemical pollutants.

One spider plant in a 10 inch hanging basket will keep the air clean in an average room, NASA says.  Keep it alive and happy by allowing the plant to become almost bone dry between watering, using room temperature water.  Anything from a north window to full sun is suitable exposure.  Resist an urge to repot at this time of year, likewise fertilizing, at least until next month.  All except flowering indoor plants are best kept almost dormant during the first couple of months of the new year.

Perhaps you might wish, while happily thus caring for your houseplants, to contemplate whether Australian research might also be a “myth.”

There were a few years there when Sheridan, hit by cost factors, decided to forgo the full-blown catalogue we had all come to rely upon.  Now fortunately we have their “Garden Guide”.  The arrival of the second millennium marks the 85^th anniversary of this venerable but vibrant nursery.  Incidentally, Howard Dunnington-Grubb first had a small garden centre at Bay and Charles Streets in Toronto.  Every Torontonian pays homage to him, however, every time they travel on University Avenue.  Sheridan nurseries took its name from a village north of Oakville in 1913.  Today they have over 1,900 acres in southern Ontario and sell not only in Canada but to the United Stares and even as far as Europe.  The catalogue costs $2.99 at any of their many garden centres in and around Toronto.

"We like your columns” readers say, “but where else can we get reliable local information?”  Landscape Ontario is a professional association of those engaged in horticulture.  In response to just such queries, they have “Garden Talk” a telephone line, which will assist, Toll free 1-800-260-8075.  If you need a professional in your area follow this up with 399, leave your name and address, and L.O. will mail out names and addresses of experts close to you.  If you are in a hurry and have a computer, try www.landscapeontario.com .

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