Since organic gardening has changed from a novelty to a commonplace way to grow ornamental plants, manufacturers have responded to gardeners’ demands for effective but natural pest-control products. These natural garden remedies are no longer exclusive to specialty nurseries and mail-order catalogs; instead, one can purchase a range of nontoxic garden supplies even at neighborhood discount or home improvement stores.
However, these organic flower garden treatments sometimes come with a premium price tag. This may discourage flower gardeners from using natural pest deterrents—after all, we usually don’t eat our flowers, so why does it matter?
There are many reasons to grow flowers organically, including the need to foil recalcitrant pests that seem immune to the expensive ready-to-use products sold on store shelves. Even the dyed-in-the-wool organic flower gardener who generally avoids pesticides can appreciate the ability to formulate homemade garden remedies to control stubborn perennial insect pests. Gardeners can turn to their pantries, gardens, and even the pests themselves to create potent plant remedies and cures that cost just pennies. Here are some easy homemade organic pest-control solutions you can try.
Homemade Insect Soap
Insect soaps are available in any organic gardening aisle, but gardeners can make a homemade garden spray that’s just as effective for aphids, caterpillars, and mites. Combine three drops of mild dishwashing liquid in one quart of water. An added tablespoon of cooking oil helps the mixture cling to leaves. Spray plants to the point of drenching, but don’t use on blossoms or when temperatures are over 80 degrees Fahrenheit to prevent scorching the plants.
Garlic has natural antibacterial, antiviral, and anti-fungal properties, and it is also a potent pesticide. Peel and crush five garlic bulbs and mix with 16 oz. of water. Let the garlic infuse in the water overnight. Add a dash of dish soap to the mixture, then strain it through a fine strainer. Dilute this liquid in a gallon of water, then place in a spray bottle. Spray this solution on your plants once or twice a week to control most insect pests.
Homemade Tobacco Spray
Everyone is familiar with the negative health effects of cigarettes, but the nicotine in tobacco is poisonous to all kinds of insects, as well. Gather enough cigarette butts to harvest a ¼ cup of tobacco leaves. Place these in a sock, and soak them in a quart of water overnight. Avoid using this homemade insect spray on members of the nightshade family, like petunias, datura, and nicotiana flowers, as tobacco can harbor the mosaic virus, which affects this family of plants.
Epsom Salt Pesticide
Epsom salts can be either be sprinkled around plants or dissolved in water to make a spray. To make a spray, dissolve one cup of salts in five gallons of water, then pour into a spray bottom and apply to any pest-afflicted plants. The salt mixture is especially effective on slugs and beetles. Another option is to sprinkle the salts around the base of the plants every week or so. It will deter pests, and also add magnesium to the soil, which increases the absorption of nutrients by the plants.
An effective insecticidal spray can be made with two very simple ingredients: soap and oil. Oil spray works by coating enclosing and smothering soft-body insects, such as aphids and mites. Mix a cup of vegetable oil with a quarter cup of liquid soap and shake it well. This concentrate can be stored until you need it. When treating plants, mix one tablespoon of this concentrated liquid with four cups of water. Best results require reapplication once a week.
Hot Pepper Bug Repellent
Even for gardeners without a penchant for spicy foods, it’s worth adding a row of hot chili pepper plants to the garden for their bug-repelling effects. Place a handful of dried hot peppers in the food processor, seeds and all, and grind to dust. Take care not to get the dust on your skin or eyes. Sprinkle around garden plants to repel ants and whiteflies. For more sticking power, add 1/2 cup of ground chili peppers to a quart of fine horticultural oil, and mist the tops and undersides of flower foliage.
A simple citrus spray is effective at killing aphids and some other soft-bodied insects. Grate the rind from one lemon, and add it to a pint of boiling water just removed from the heat. Allow the mixture to steep overnight, then strain through cheesecloth or a fine sieve. Pour the mixture into a spray bottom and apply to both the tops and bottoms of the leaves on afflicted plants. This mixture must contact the insects in order to be effective.
Rubbing Alcohol Bug Spray
Rubbing alcohol quickly desiccates the bodies of soft sucking pests such as aphids, mealy bugs, and thrips.
Rubbing alcohol can also damage plant tissues, so gardeners should use alcohol sparingly in the garden.
The best way to apply is by dabbing a cotton swab soaked with rubbing alcohol directly on the pests, taking care to avoid the plant itself. Plants with waxy leaves may tolerate a dilute alcohol spray of one-cup alcohol mixed with a quart of water. This is a favorite way of quickly dispensing of orchid pests.
Bug Juice Spray
Gardeners may be repulsed yet fascinated to learn that one can make a natural bug spray out of the pests themselves. No one is exactly sure why pests are their own worst enemies when applied to plants, but researchers speculate an anti-cannibalism mechanism or the presence of a chemical that inhibits insect feeding. Gather enough of the offending pests to fill at least a teaspoon, and pulverize them with the back of a spoon. Place the mashed bugs in cheesecloth, and soak in two cups of water overnight. For best results, use the bug juice within three days.
Therapeutic Uses and Pharmacological Properties of Garlic, Shallot, and Their Biologically Active Compounds. Iran J Basic Med Sci. 2013 Oct; 16(10): 1031–1048