Natural Solutions that Work
By Jennifer Bennett
UPdate Summer 1995

The labels on pesticides may be beautiful, showing apples as round and read as babies’ cheeks, roses as speckles as Playboy centerfolds, and lawns as brilliantly green and even as the plastic turf in the Astrodome.  The fine print on the back of the box tells a different story, however: “Do not apply to a food crop within 10 days of harvest”; “Avoid inhaling spray mist or contact with skin, eyes or clothing”; “Keep children and pets away from treated area during application and until dry.”

Garden stores devote entire aisles to packages like this, with bright labels and toxic contents that suggest a garden both untouchable and medible.  I am amazed to see people who look as though they would never think of smoking blithely picking up armloads of poisons to spray on the garden, a place meant to be beautiful, approachable and nurturing.

Behind the warnings on pesticide labels is an accumulating body of evidence showing that these chemicals – formulated to kill insects, fungi or weeds – are harmful to many living things other than just the target pests or diseases (which are, in any case, rapidly developing resistance to every pesticide formulated to kill them).  Health problems, many of them documented in medical journals, vary from allergic responses and lowered sperm counts to lung damage, cancer and death.

Furthermore, less than one-tenth of one per cent of the pesticide may contact the target insect.  The remainder is dispersed into the air, soil or water to become an environmental contaminant, polluting wells and lakes and killing honeybees, fish and other wildlife.  A general deterioration worldwide in the safety of air and water can be blamed in part upon agricultural chemicals.  Although home gardeners might think that the small amount they use will make little difference, studies in the U.S. have shown that acre for acre, home gardeners use four times as much pesticide as farmers. 
Gardening Wisely
So what is a conscientious gardener to do? First, stop buying and using synthetic pesticides.  Just as important, alter your gardening expectations.  The perfect produce you see pictured on the pesticide labels may demand too high an environmental price (perfection may not come with using the product anyway).  Spots on the apples and specks on the roses may be better for you than the cure for spots and specks.  Choose disease-resistant plants wherever possible.  

The next thing to pay attention to is overall garden health, which means looking not just at the plants, but also at the soil and at the garden’s supply of sunlight and water.  A garden is best able to resists pests and diseases if plants have been chosen to suit the growing conditions.  Most vegetables require several hours of full sun a day and deep soil with lots of organic matter such as compost.  Plants should not be overcrowded.  Watering should be infrequent but thorough.  Use air temperature water if possible.  Rainwater collected in barrels from the eavestroughs is perfect.  Take a walk through your garden every day, if possible, so that you will see pests or disease problems as soon as they appear.  Mechanical means of getting rid of pests are, of course, the safest: squishing, trapping, brushing off.  Attract insect-eating birds by installing birdhouses and baths.  Dormant oil and sulphur sprayed on fruit trees in early spring takes care of many overwintering pests.  Another mechanical cure is diatomaceous earth, with is marketed in some garden stores.  It acts as an abrasive barrier to a variety of crawling insects.  An effective remedy for preventing fungal diseases is plain old baking soda.  Add one teaspoon of soda to a litre of water and spray flowers and vegetables once a week.

Benign Sprays
If you do decide to spray, there are several fairly benign products on the market.  Botanical pesticides – substances made from plants – can be just as toxic as the synthetics when applied.  They kill beneficial insects as well as pests, but have the advantage of degrading quickly into harmless by-products.  The most common are rotenone and pyrethrum.  Rotenone, made from the roots of certain tropical plants, kills a wide range of pests, including Colorado potato beetles, squash beetles and cucumber beetles.  It is a powerful toxin that can harm people and is deadly to fish, so it must be applied with care on a calm, unwindy day and kept away from bodies of water.  Pyrethrum, made from pyrethrum daisies, is similar, though far less dangerous to humans than rotenone.  Pyrethrins are the active ingredients.  Pyrethroids, synthetic versions of pyrethrins, are common in indoor pesticides, but they may have more dangerous side effects than botanical pyrethrins.  

Herbs Triumph Over Pests
Soap is another relatively safe spray.  It kills pests and also acts as a deterent to creatures that might otherwise munch.  There are several formulations on the market, ready to spray, or you may want to try making your own.  Almost every organic gardener has a favourite recipe, usually fortified with herbs and other plants that contain insecticidal ingredients themselves – pressed garlic, cayenne, citrus peels.  Here is one that works for me: to a litre (one quart) of rain water – soft water works better than hard – add two crushed cloves of garlic and one tablespoon of plain, unscented dish detergent, stir, let steep for a couple of hours and spray.  This will wash off plants when it rains, so it must be reapplied whenever pests are seen.


Jennifer Bennett, who lives near Kingston, Ontario, is author of The Harrowsmith Northern Gardener and Lilies of the Hearth.