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Are you growing a vegetable garden this summer? Once seedlings begin sprouting up, it’s time to think about guarding your garden against pests. These sneaky little nibblers will gnaw on leaves, stems, and roots, killing your plant directly or slowly poisoning them. You can buy commercial insecticides and kill the bugs, but those bug-killing chemicals also end up on your garden veggies. Want to keep your garden organic? Use some natural pest-deterrent methods that are equally effective and 100% safe for humans and pets. Let’s talk about Organic Garden Pest Control!
Who is the Enemy?
Common garden pests will vary by region, soil conditions, and plants, but here are some of the top offenders in my neck of the woods. Any of these little guys sound familiar? What else have you had to fight off?
|
Pest |
How It Affects Your Plant |
Signs of Damage |
|
Aphids |
Suck plant sap and produce honeydew. Feeding spreads viral diseases. Honeydew encourages mold growth. |
Honeydew (sticky liquid) left behind on leaves. Leaves will droop and distort. |
|
Thrips |
Drain cellular fluids from leaves. May transmit plant diseases. |
The leaves are left in tact but drained of all fluid. The cell structure remains, leaving a silvery look to the leaf. |
|
Tomato Hornworms |
Chew on leaves and stems, causing massive damage very quickly. |
Chewed/missing leaves. |
|
Whiteflies |
Whitefly larvae suck plant sap and produce honeydew. Honeydew encourages mold growth. |
Look for honeydew on the leaves and yellowing leaf color. Mold may also be present. |
|
Squash Bugs |
Slash the plant and drain out the liquid, causing noticeable damage quickly and can also kill the plant directly. May also feed on fruit, allowing disease to enter easily. |
Pictured below. Early signs: leaves show speckling and may turn yellow. Advanced signs: leaves turn brown, vines die, young fruit dies. Squash bugs are large and easily identified. |
Your Options: To protect your vegetable garden from six-legged invaders, you have two options: kill them or repel them. Today, we’re going to focus on all-natural insecticide options to kill garden pests.
DIY Insecticides for the Organic Garden
Commercial insecticides work by getting into the bug’s system and poisoning it, causing a chemical or mechanical rection and leading to death. There are stomach insecticides that work after being ingested by the bug, and contact insecticides that are absorbed through the bug’s body. Either way, the desired effect has been achieved and the bug is dead. Regrettably, these insecticides have some pretty significant drawbacks. They can be dangerous to humans and pets, can create increasingly toxic chemicals after getting into the environment, will kill off ALL bugs including the desirable pollinators, and some insects are showing resistance to the chemical insecticides.
Good news: you have options. Great ones. Affordable ones, and they’re probably already on hand. You don’t have to search too hard to find homemade insecticide alternatives. DIY recipes are common and sometimes preferred by gardeners. Why? Because they work. Don’t you love it when the all-natural option is just as effective as the synthetic option? Throw out your store bought insecticides (in a safe, EPA approved method), and cook up one of these homemade bug killers.
|
DIY Insecticide |
Recipe |
Primary Targets |
Usage |
|
Garlic Oil Spray |
In a blender, combine 1 head of garlic, 2 tablespoons vegetable oil, and 2 cups water. Blend. Store in the fridge overnight, and then strain out the garlic in the morning as you transfer the liquid into a spray bottle. Add one tablespoon dish soap. |
Whiteflies, aphids, beetles |
Spray liberally on and under leaves. This solution will kill bugs with direct contact, and the garlic works as a repellent as well. |
|
Hot Pepper Spray |
In a blender, combine 1/2 cup raw peppers (Thai chili, serrano, habañero, jalapeño, etc.) and 2 cups water. Puree peppers and water. Let sit overnight. Strain peppers out as you transfer the liquid into a spray bottle. Add 2 tablespoons dish soap. |
Effective against all pests, especially mites. Bonus: repels deer, squirrels, and other small critters as well. |
Spray liberally on and under leaves. The soap will kill bugs with direct contact, and the pepper will act as a deterrent. Caution: irritating to humans and animals. Avoid contact with eyes and nose. |
|
Simple Soap Spray |
In a spray bottle, combine 2 cups water with 2 teaspoons liquid dish soap. |
Most effective against soft-bodied insects (aphids, whiteflies, spider mites) |
Spray directly on insect. Works only as an insecticide on contact, and does not work as a deterrent. |
|
Beer Bowl Trap |
In your garden, place a clean tuna can tin (or other shallow bowl, pie plate), about 1” below the soil line. Fill it with a couple inches of beer. |
Slugs |
Slugs are attracted to the beer, slither down into it, and drown in the liquid. Check daily, empty, and refill. |
|
Diatomaceous Earth (DE) |
Buy food grade DE (not pool grade) and sprinkle directly on plants. Use dry. |
Will kill any insect with an exoskeleton! Acts a deterrent to slugs and snails. |
Works as a stomach insecticide. If you water the garden or if it rains, you need to reapply DE. Bonus: can also be used inside the home. It is harmless to humans and pets. |
|
Self-Rising Flour |
Sprinkle on cabbage plants or any other plant suffering worm damage. Worms eat the flour and swell up, causing death. |
Cabbage worms, maggots, larvae |
The leavening agents in self-rising flour will expand when ingested by the worms, causing a quick death. Apply early in the morning when worms are active. |
|
Potato Lures |
Slice a potato into fourths and pierce with a long, bamboo skewer. Bury in your garden’s soil. |
Root-eating bugs |
Potatoes attract any root-munching insects. Every couple days, remove the potato lures, kill the feasting bugs. Repeat. The potato will lure bugs away from your plants’ roots. |
Repel Insects with Essential Oils
-Adding essential oils to your pest control sprays and around your garden will help repel insects.
-Peppermint: aphids, beetles, caterpillars, squash bugs, tomato hornworms
-Lavender: ants, aphids, beetles, fleas, flies, moths, ticks, whiteflies
-Cedar: aphids, moths, rodents, slugs, snails, weevils
-Lemon (and other citrus): aphids, squash bugs
-Basil: flies, mosquitoes, squash bugs
How to Use Essential Oils in Your Garden:
-
Add 15 drops of essential oil(s) to 2 cups of water in a spray bottle and spray on plants.
-
Add to your DIY Insecticide mixtures.
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Soak a small strip of cloth in your oil(s) and tie around a strong stalk or on a stake near the plants.
-
Add a few drops of oil(s) onto cotton balls and place throughout the garden.
The fragrance of oils will dissipate over time, reducing their effectiveness. Plan on refreshing essential oils in your garden every 2-3 days or after a heavy rain.
My hesitation? Essential oils are expensive. If you already have some on hand and need to control/prevent a pest situation, go for it! However, if you don’t need them, save your money and save your oils. Want to give them a try? Start with peppermint and/or lavender oils. They are relatively inexpensive and handy for other household uses.
Warning: Kill the Bugs, Not Your Plants
There are a few important rules to consider to protect your garden from collateral damage.
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Test It. Before spraying anything all over your garden, test it. Apply the spray/treatment in a small section of your garden and wait 48 hours. Some soaps may be too be harsh for your plants. Some plants may be more sensitive than others. If you see a bad reaction, tweak the recipe. Maybe use a milder soap or skip the soap altogether and buy some diatomaceous earth.
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Timing. Spray-on insecticides should never be applied to wilted leaves. Water plants the day before insecticide application and choose a cloudy day to treat your plants. Dry conditions and bright sun will accelerate leaf damage.
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Rinse. If you have to use insecticides on a bright, sunny day, rinse it off after it’s done its job. This will help prevent damage to the leaves.
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Be Conservative. Insecticides do not discriminate harmful bugs from beneficial bugs. They will kill desirable pollinators and predatory insects just as quickly as hungry caterpillars. If you can remove offending bugs by hand, you can protect the good bugs and your plants. Pluck bugs and drop into a bucket of soapy water to kill them. To remove eggs from leaves, use a piece of masking tape to pull of the eggs without damaging the leaf.
Do you have any more tips to share? I’m still learning so much about how to keep a healthy, organic garden. Share your knowledge, experience, and pointers with us all!
Next week: Repel Insects Naturally with Companion Gardening
Would you rather not spend your free time hunting down and killing bugs? With a little planning, you can keep the bugs away or under control, just by adding the right plants! Next week, we’ll discuss some all natural pest-prevention methods including companion gardening and introducing predatory insects.
This is part of an Organic Living Journey Guest Post Series now written by Mariana who has a mother’s heart and scientist’s brain.
