The Only Chemical-Free Pesticide Guide You’ll Ever Need

There’s nothing worse than watching your plants suffer at the jaws of some unknown insect. But before you reach for those hard-to-pronounce and toxic chemicals, know that you do have safer, and often cheaper pest management options.

The next time your garden turns into a feeding frenzy, consider the following all-natural pest-killing substances. Beneficial insects, diatomaceous earth, neem oil, companion planting, and insect soap are just five of the many chemical-free techniques to manage pest invasions organically.

Read on to learn how to use these nontoxic pesticides for your healthiest garden yet!

All about pesticides

Pesticides are substances that are used to kill, repel, and prevent pests from damaging crops. Pesticides can be broken down into three different categories–insecticides that target insects, herbicides that kill weeds, and fungicides that fight fungus. 

Why skip conventional chemicals

Most synthetic pesticides contain harmful carcinogenic chemicals that run the risk of injuring you, your family, your pets, and even your plants themselves. Pesticides have negative implications for the environment too--the same chemicals that kill bad bugs will also damage your garden’s population of beneficial insects and pollinators.

Healthy soil is comprised of billions of microorganisms, and conventional pesticides will obliterate them all. Birds and other animals that visit your garden may also be affected. While the soil does absorb some pesticides reside, most of the chemicals become surface runoff and wind up in the local watershed.

Conventional pesticides can also become a financial burden. The pesticides themselves are expensive, and over time the pests develop immunity to the chemicals, so eventually, you have to use more of the same pesticides to get the same results. 

Aim for an ounce of prevention

You’ve heard it before: an ounce of prevention is worth a pound of cure. 

The best chemical-free defense, and the best defense in general, against pest infestations and diseases, is to raise healthy plants. Stressed plants–whether starved of sunlight, nutrients, or water–are the first to succumb to pests and disease. 

Ensure that your plants are healthy from the beginning by starting with quality seeds and seedlings that are transplanted out into the garden at the right time. Give your young and mature plants adequate water, but don’t overwater them as this creates weak root systems. Incorporate compost into the beds before planting, and fertilize with a balanced organic fertilizer and/or compost tea throughout the season to ensure your plants have everything they need to fight off potential infections. 

How to use biodegradable pesticides 

All-natural compounds come in a variety of forms, but sprays and powders are the most common. Unlike conventional pesticides, nontoxic pesticides are gentle enough to be used regularly to treat current infestations or applied preventatively to curb an infestation before it even occurs. 

Dust

Powdered pesticides, often called dust, need to be applied via a pesticide duster like this one. Dusters are safer to use than spreading dust by hand, and they more thoroughly cover the intended area. Only fill the duster a third of the way full so that there’s enough room for air to move through the equipment. 

Try to leave a thin, uniform layer of dust–apply the dust too thickly, and insects will avoid it, but if you just barely cover the area, then insects will walk right into it. 

Sprays

To apply pesticides as a spray, you’ll need a pump sprayer (best for large plantings) or a spray bottle or mister (best for spot treatment on just a few plants). Unless the product is labeled “ready to use,” you’ll need to dilute the product per the instructions on the label.

Whatever you spray, spray either early in the morning or late in the evening. Avoid the hottest part of the day and water the plants previously to avoid stressing the plants even further. It’s always a good idea to do a small patch test any time you introduce a new substance or a new plant into your spray regimen. 

Always wear protective clothing when applying any pesticide. Even organic and all-natural products are still highly concentrated substances that can do damage. Wear eye protection, gloves, a mask, and long sleeves and pants when using any concentrated substance.

5 nontoxic pesticides for a chemical-free garden

1. Beneficial insects

   The first line of defense in pest prevention is to take advantage of naturally-occurring predatory insects in your environment. Ladybugs, green lacewings, hoverflies, and braconid wasps are native to many parts of North America. If you don’t have existing populations of beneficial insects, you can order eggs, larvae, and hatched adults from online retailers like Grow Organic or Planet Natural.

   Predatory insects are best as a preventative measure and for pest management since the insects can only eat so many pests per day. If you wait to order predatory insects until a full-blown invasion, it might be too late for beneficial insects to be effective.

2. Diatomaceous earth

   Diatomaceous earth, or DE, is the secret weapon in the arsenal of non-toxic pest management. 

   DE is a white powder made from fossilized skeletons of marine animals, and it’s a miracle worker in the garden. While the powder is virtually harmless to humans, pets, and plants, it causes serious damage to most insects. When insects come into contact with the powder, DE cuts through insect exoskeletons, drying out their bodies and causing them to die within days.

   DE is easy to apply–simply take an empty salt shaker and dust your plants and surrounding soil with a fine layer. Wear a mask and take care not to breathe the dust, as it may irritate your lungs. Wait until your plants are dry before applying–DE is rendered ineffective when wet, so always reapply after watering your plants or after a rain. 

3. Neem oil

   Neem oil is a concentrate that comes from the neem tree. It’s a powerful substance that is very effective at suffocating and killing soft-bodied insects like aphids, mites, thrips, and whiteflies. 

   Neem oil is usually sold as a concentrate, so be sure to dilute it prior to use unless you buy a ‘ready to spray’ variety. Follow the dilution instructions on the container, but a good rule of thumb is to use ¼ tsp of neem oil for a 16oz spray bottle.

   Neem oil is quick to decompose–it’s really only effective as soon as it’s sprayed. Once neem oil dries, it loses its potency, making this a safe substance to use on a variety of plants. Do a small patch test before you spray the whole plant, but neem oil is generally safe enough to apply every three days to exterminate a current infestation or treat once weekly as a preventative measure. 

4. Companion planting

   As simple as it sounds, diversifying your garden is one of the best ways to protect your plants. Monocultures are a sure way to invite large-scale damage into your garden, but incorporating variety into your garden provides a kind of safety net–should one crop fail, not all will be lost. 

   Be strategic with your garden planning–some plants, like nasturtiums or sunflowers, make the perfect “trap crops” for aphids and other pests. The bugs are attracted to the flowering plants, leaving your vegetables alone. Other plants, like onions, actually repel pests that target specific crops, like the carrot fly.

5. Homemade insecticidal soap

   Make your own bug soap out of ingredients you already have on hand! All you need is a bottle of castile soap and a spray bottle. 

   To make the insecticide, pour ½ tablespoon of castile soap into a 16-ounce spray bottle. Add ⅛ tablespoon of vegetable oil as a bonding agent, and fill the bottle with water. Cap the bottle and shake to mix, and your homemade insecticide is ready to use! 

   For larger batches or to make the spray ahead of time, you can use one tablespoon of castile soap and ½ tablespoon of vegetable oil for every quart of water. For a more thorough pesticide, you can substitute neem oil for vegetable oil.

   Take note of how your plants and the pests react to your homemade spray and adjust as needed until the pests have disappeared. Wait at least three days in-between applications. 

In summary

All in all, plants not treated with pesticides are healthier than plants that are treated and better equipped to fight off infestations and infections on their own than plants exposed to synthetic chemicals. When pests and diseases do get out of control, opt for all-natural substances whenever possible. You might be surprised at how effective chemical-free pesticides can be!