How to Use Organic Pesticides for Gardening

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methods

1Choosing an Organic Pesticide

2Applying the Pesticide Effectively

3Using Alternative Methods

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Expert Q&A

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Tips and Warnings

Things You'll Need

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References

There are hundreds of pesticides on the market and trying to figure out which products are actually safe can drive you crazy. Figuring out which organic product to use is even more complicated, since the term “organic” does not automatically mean that there are no dangerous chemicals in the product; it simply means that none of the ingredients are synthetic. However, when it comes to natural pest control, there are several organic pesticides that are hands down safer and more effective than other options out there.

Steps

Method 1

Method 1 of 3:

Choosing an Organic Pesticide

1. 
   1
   Use neem oil during the growing season to control common pests. Neem oil is one of the most popular organic pesticides for a reason. It coats plants in a protective layer of oil that suffocates many common pests like whiteflies, aphids, beetles, and spider mites. Since neem oil is lighter than horticultural oil, it’s a better choice for summer months when you don’t want to cover your plants in a thicker material that may make it harder for plants to grow.

   • Neem oil comes from the seeds of the neem tree. It’s one of the best pesticides because it’s largely nontoxic to humans and mammals. It also targets a wide range of pests, which makes it a great general pesticide.
2. 
   2
   Select horticultural oil to protect overwintering plants in the off season. Horticultural oils is similar to neem oil, but it’s a little thicker and stronger. Similar to neem oil, it coats plants in a layer of oil that suffocates many common pests. However, since it’s thicker, it’s better to use horticultural oil in the fall and early spring when plants can benefit from a thicker protective layer.

   • Horticultural oil is typically made out of a combination of vegetable oil, petroleum, and some natural insecticides. Like neem oil, it’s largely nontoxic to mammals and humans.
   • Do not apply horticultural oil when it’s under 40 °F (4 °C). Luckily, you really don’t need to worry about pests when it’s this cold, though.
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3. 
   3
   Choose beauveria bassiana if you have mites, thrips, aphids, or whiteflies. Beauveria bassiana is a fungus that grows naturally in certain soils. It’s a parasitic fungus that attacks common pests like mites, thrips, and other bugs that attack garden plants. If you’re one of these pests has infiltrated your garden, pick up an organic pesticide that lists beauveria bassiana as its central ingredient.

   • Beauveria bassiana is the most common ingredient used to combat kill bedbugs. It will also target beetles, fire ants, grasshoppers, stink bugs, and weevils.
   • Beauveria bassiana is generally safe around people, but you may be at risk of an infection if the fungus gets into your lungs or ears and you’re immunosuppressed (i.e. you have HIV, or are going through cancer treatments).
4. 
   4
   Opt for bacillus thuringiensis (BT) if you have caterpillars, worms, or mosquitoes. Pick up an insecticide that lists BT on the label as its main ingredient if you’re dealing with one of these pests. BT is a natural bacteria that attracts certain insects to eat it. When consumed, the BT eats through the insect’s stomach and kills them.

   • BT is an attractive meal for some other bugs, but it will really do a number on caterpillars.
   • BT can cause some minor damage to sensitive plants, but it’s perfectly safe for humans and mammals.
5. 
   5
   Choose an organic bicarbonate product to control fungi. If you’re dealing with a fungus in your garden, pick up an organic pesticide that contains sodium bicarbonate, which is the fancy scientific name for baking soda. Baking soda on its own isn’t great at fighting fungus, but when mixed with an oil-based product (like neem or horticultural oil), it’s great at killing common fungal infections.

   • Baking soda on its own will damage your plants since the it will leave a toxic residue behind as it gets wet and dries out over and over.
6. 
   6
   Use diatomaceous earth to deter beetles, roaches, and fleas. Diatomaceous earth is a natural sililica-based rock that is crumpled up into a fine powder. It’s often premixed into gardening soil since it deters pests without damaging plants. Pick up a bag of diatomaceous earth to keep cockroaches, beetles, and fleas out of your garden.

   • Diatomaceous earth is safe for humans. In fact, a food-grade version of the stuff is found in toothpaste, skin creams, medicine, and water filters.
   • Diatomaceous earth absorbs the oils and fats in the insect’s exoskeleton. This causes them to die or leave the area and look for a safer place to stay.
7. 
   7
   Avoid products with arsenic, strychnine, or nicotine sulfate. Each of these ingredients are organic, but they aren’t really safe for humans. Since there are so many good options on the market, there’s no real reason to choose an insecticide with any of these ingredients in them. When selecting a product, scan the ingredient list to make sure these ingredients aren’t listed.

   • Rotenone, Ryania, and sabadilla are also toxic, although they’re much less common.
   • Nicotine sulfate is also known as tobacco dust. These are basically the same thing.
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Method 2

Method 2 of 3:

Applying the Pesticide Effectively

1. 
   1
   Read the label carefully and follow the instructions on the product. Every organic pesticide is applied differently. Even manufacturers that make the same product have different application instructions. Read the label thoroughly to follow the instructions and apply the product safely and effectively.

   Warning: You typically don’t need safety equipment to apply oils, but you may need a respirator or dust mask if you’re working with beauveria bassiana. Just read the label to see what kind of safety gear you need.
2. 
   2
   Spray ready-to-use neem and horticultural oil to cover your plants entirely. Neem and horticultural oil are typically pretty easy to apply. Just take the spray bottle out into your garden, turn the nozzle to the widest spray setting, and mist your plants directly. Don’t forget to hold the nozzle under the leaves and spray the undersides as well!

   • You typically apply neem or horticultural oil every 7-14 days until the pest is gone. You can also spray it monthly as a preventative measure if you’re worried about pests showing up.
3. 
   3
   Spread BT and bicarbonate around your plants and soil with a duster. BT and bicarbonate products typically come in powdered forms. Load your duster’s canister up and pump it around your plants to coat them in the powder. You can also take an empty plastic bottle, fill it with the powder, and poke holes in the top of the bottle to dust you plants manually.

   • Usually, you apply BT or bicarbonate products every 7-10 days until there are no longer pests.
   • Some of these products are water-activated and need to be mixed with water before spraying them on your plants.
   • Wear a dust mask if you want to avoid breathing these products in and you’re using a bigger duster.
4. 
   4
   Mix beauveria bassiana with cold water before misting your plants. Beauveria bassiana is a fungus that needs to be activated with water to grow. Grab an empty spray and add roughly ½ teaspoon (2 grams) of beacuveria bassiana for every 0.25 US gal (0.95 L) of water and mix it with a wooden spoon for 1-2 minutes. Then, mist your plants and soil thoroughly to cover them in the predatory fungus.

   • Pests will typically die 3-5 days after you apply the fungus. If you see any bugs with a white powder on them, it’s working!
   • Reapply the beacuveria bassiana every 5-7 days until the pests are gone.
5. 
   5
   Spread diatomaceous earth around the plants in your garden to apply it. Take your bag of diatomaceous earth and tear a corner of the bag off. Pour it directly over the soil to spread it around your plants to keep pests away. If you’re dealing with an active infestation, pour some directly on your plants as well.

   • The diatomaceous earth will continue to work so long as it’s dry and not windy. You may need to reapply more of it whenever it rains or gets windy, though.
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Method 3

Method 3 of 3:

Using Alternative Methods

1. 
   1
   Cover your plants in fabric row covers to keep pests off. Pick up some prefabricated row covers and lay them down over your plants. Either pin the covers down or place heavy objects along the edges to keep them in place. This won’t protect your plants from pests already on your plants, but it will keep many bugs from landing on your flowers or bushes as they grow!

   • Professional farmers and plant nurseries typically use fabric covers to protect their plants when they’re young.
   • Row covers will keep moths, large beetles, aphids, and fleas off of your plants.
2. 
   2
   Lay down some sticky traps to catch beetles, whiteflies, and leafhoppers. Sticky traps are bright pieces of foam material covered in a glue. The color attracts certain predatory bugs and keeps them running around your garden. This is a great option if you want to confirm a suspicion about a specific pest since you can capture a specimen and take a deeper look.

   • These traps also attract fruit flies, scales, gnats, midges, mealybugs, and thrips.
3. 
   3
   Introduce some beneficial insects to hunt specific pests. Many insects are good for your garden, and you can buy certain beneficial insects and release them in your garden to control pests. This is a great option if you have a strong garden set up and you’re worried about damaging your plants. They’re also a great choice if you have a few beneficial bugs that you don’t want to kill accidentally with an oil or pesticide.

   Targeting Specific Bugs:
   

   Ladybugs – Ladybugs will target aphids, insect eggs, and mealybugs. They’re savage predators that will hang out until all of the pests are gone.
   

   Lacewings – Lacewings are strong predators that kill aphids, moth eggs, scale, and basically any other small insect. The main downside is that they smell kind of bad and can cost more than other predatory bugs.
   

   Predatory mites – Predatory mites target other mites. They’re really cheap and will absolutely decimate mite colonies before leaving your garden.
   

   Ground beetles – Ground beetles are great for caterpillars and grubs. They’ll also attack snails and slugs if these are an issue. Unfortunately, they’re kind of big and may freak you out if large bugs bother you.

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Expert Q&A

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• Question

  What should I spray on my organic garden?

  

  Steve Masley
  Home & Garden Specialist

  Steve Masley has been designing and maintaining organic vegetable gardens in the San Francisco Bay Area for over 30 years. He is an Organic Gardening Consultant and Founder of Grow-It-Organically, a website that teaches clients and students the ins and outs of organic vegetable gardening. In 2007 and 2008, Steve taught the Local Sustainable Agriculture Field Practicum at Stanford University.

  

  Steve Masley

  Home & Garden Specialist

  Expert Answer

  You can make your own horticultural oil and spray it to get rid of insects. Mix a teaspoon of dish soap and a teaspoon of vegetable oil in a pump spray bottle, and spray it on your plants where you see bugs. You can even add chili oil or garlic oil to the spray help prevent the bugs from coming back for a week or so."

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• Question

  How do I deter mice in a garden?

  

  Community Answer

  There are mint based sprays for use in organic gardening. They will need to be applied frequently, particularly after it rains. Other options may be to use the urine of a predator, such as a fox. Check to see if that will conform with "organic." There are home-made preparations using capsaicin (the ingredient in hot peppers). If you make/use this, you MUST use eye and skin protection! White vinegar will help remove the capsaicin from your skin, but prevention is better than treatment. Anything you use will need to be applied after each rain.

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• Question

  What can I use at home as a fertilizer for my veggies?

  

  Community Answer

  A mixture of seaweed root-booster such as Seasol and fish fertilizer, such as Charlie Carp (that's liquid rotten fish, but it doesn't smell near as bad as you expect) does a marvelous job, and is also great for things like strawberries and blueberries.

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Video

Tips

• Every garden is different. If a certain organic pesticide isn’t working out, try switching your strategy up.
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• While they generally aren’t as effective as the stuff you can buy, you can always try making your own pesticides to combat certain pests.
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Warnings

• Read labels carefully and research any ingredients you don’t recognize. Organic pesticides are often just as dangerous as synthetic pesticides.
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Things You’ll Need

• Spray bottle
• Duster
• Dust mask
• Respirator