Organic Gardening and… Pesticides?

26 Aug

PesticideContrary to popular belief, the term “organic” is not a promise that something is pesticide-free, or free of chemicals. In fact, most state laws allow the use of a wide variety of chemicals in organic farming.

Then, what exactly does the term “organic” mean? It means that any pesticides used must be derived from a natural source – not synthetically manufactured. And the equipment used to apply these pesticides must not have been used to apply synthetic pesticides within the past three years.

It also means that the land being farmed must be free of synthetically manufactured pesticides for a period of three years as well.

So, does this mean that organic produce is “safer” for human consumption than conventionally farmed produce? Of course, studies have been done on synthetic pesticides, and several have been found to contain carcinogens. But, what about the organic pesticides – are they safe?

When studies were done on organic pesticides, it was found that several of them were carcinogenic as well. It has long been assumed that natural, organic pesticides were safer and somehow better than synthetic chemical pesticides.

However, it seems that not enough research has been done to say that natural, organic pesticides are truly “safe” to put on the produce that we eat. Not enough research has been done to know, for sure, how long natural, organic pesticides will persist in our environment.

So, what types of things are allowed to be used as natural, organic pesticides in organic farming and gardening? Naturally-occurring ingredients, such as fungal derivatives, plant extracts, and certain insect pathogens have long been used in organic farming and gardening.

We will list a few of the common natural, organic pesticides:

Insecticidal Soap
What it is: Sodium or potassium salts, combined with fatty acids.

Notes: Insecticidal soap needs to come into direct contact with the insects. Once it has dried it is no longer effective. The fatty acids penetrate the insect’s outer covering, causing the cells to collapse, thus killing the insects.

Insecticidal soap is considered as one of the safest pesticides. It is non-toxic to animals and leaves behind no residue.

Unfortunately, it can burn or cause stress to your plants. You will want to avoid using this on your plants during full sun or high temperatures. Some plants may be especially sensitive to insecticidal soap, so be sure to read labels carefully before using in your garden.

What it is: Azadirachtin and liminoids – both are from the seed kernals of the Neem tree fruit.

Notes: You apply Neem by spraying it directly onto your plant leaves. Neem works by upsetting the hormal system of the insect, thus preventing it from developing to full maturity. Therefore, Neem is most effective on insects that are still in their immature stage, and insects that go through a complete metamorphosis.

Neem is non-toxic to humans, but may be dangerous to pets, so keep your pets away from the garden until the leaves of your plants have dried. This pesticide will wash away in the rain and can be slow-acting, therefore it is not one of the best natural pesticides.

Bt (Bacillus Thuringiensis)
What it is: A bacteria. There are more than 80 types of Bt that are commonly used as pesticides.

Notes: Most Bt comes in powdered form. You dust or sprinkle the Bt onto your plants. The Bt must be ingested by the insects in order for it to be effective.  Bt releases toxins into the stomachs of the insects. These toxins then cause the insects to stop eating, thus causing them to starve to death.

Most Bt strains are host-specific and not considered harmful to humans, pets, bees, or birds.

Bt is another slow-acting pesticide. It may take several days for the Bt to cause the insects to stop eating. Also has been known to kill beneficial insects (i.e. butterfly larva). Is also a skin irritant, so use caution when applying Bt to your garden.

Horticultural Oil
What it is: Very highly refined petroleum oil.

Notes: To apply, you will mix the horticultural oil with water, and spray onto the leaves of your plants. The petroleum oil coats and suffocates insects, and the coating on the plants will disrupt their feeding.

It has a low toxicity to humans, birds, and pets. It does not leave behind a toxic residue. It is more effective against soft-bodied insects, rather than hard-bodied insects.

Use with caution – it can burn the leaves of your plants.

Potassium Bicarbonate
What it is: Potassium bicarbonate is colorless and odorless, and slightly salty. When used as a fungicide, it is often combined with horticultural oil – this helps to spread and completely cover the leaves of your plants.

Notes: Spray this mixture onto your plants at the first sign of fungus or disease. Or, can be used as a preventative, before you spot infection of your plants.

It lasts up to 2-3 weeks when used as a preventative. And, it is safe to use on your vegetables up to the time of harvesting.

Avoid using in full sun or extreme temperatures, as it can burn plant leaves.

What it is: A natural pesticide that is obtained from the roots of tropical legumes.

Notes: To apply, you dust it onto your plants. It will deprive insects of oxygen in their tissue cells, causing inhibited cellular process.

Rotenone leaves very little residue, and breaks down quickly in sunlight. May be harmful to bees, so apply in the evening when bees are less active.

What it is: Seeds from the Sabadilla Lily that have been ground into a fine powder.

Notes: This fine powder is mixed with water and used as a spray. It is a stomach poison for insects.

This pesticide is highly toxic to bees. It is also highly irritating to the mucous membranes of mammals.

Although considered a natural, organic pesticide, Sabadilla is dangerous, and damaging to our eco-system, and should be used as a last resort.

What it is: A powder derived from Chrysanthemum Cinerariifolium.

Notes: This powder is used by dusting it onto the leaves of your plants. The powder causes a speedy death to insects by poisoning them. It is very quick-acting, and has a low-toxicity to animals.

The powder breaks down quickly, usually degrading within a day.

This powder is considered a “broad spectrum insecticide” – meaning, it will kill any insect. For this reason, it is known to be very toxic to honeybees. Please use with caution, and only in dire circumstances. We need to protect our bees!


We must remember that, just because something is considered “organic” doesn’t necessarily deem it as “safe” or free of carcinogens. Unless you know your farmer personally, there is no way to know which pesticides were used, or how much of each pesticide was applied to the plants.

Even though foods and produce are covered in labels and stickers that boast “organic ingredients” or “organically grown,” they may not be free of harmful pesticides. And, their farmers may be contributing to the bee colony collapse that scientists have been studying in recent years.

If you are an organic gardener or farmer, please use your natural, organic pesticides carefully. Do your own research and find out which natural, organic pesticides are the safest, and the least damaging to our ecosystem.

There are so many myths and misconceptions surrounding organics and organically-grown foods. Many people fully believe that organically-grown automatically means “pesticide-free,” “eco-friendly,” “safe for all animals,” “fresher,” or that they pose less food safety risks. Many people would be very surprised by what they would discover about organics and organic farming with a few simple searches on the internet. Be sure to do your own research and educate yourself.

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