You can make your own organic insecticides if you want to avoid the chemicals and cost of store-bought products. A natural insecticide created at home uses fewer ingredients and is inexpensive when compared to commercial options. If you use organic products, you can ensure there are no pesticides in the mixture. Sprays are easy to make and can contain a combination of effective ingredients. Natural dry insecticides prevent bugs from devouring plants and also work as fungicides. Organic insecticides also can provide a humane deterrent to larger garden pests, such as squirrels, rabbits and groundhogs.
You can make water-based bug sprays using items found at the supermarket. Each ingredient deters a variety of pests in a natural and harmless way. You can purchase a plastic spray bottle for around $1. If you prefer to recycle a spray bottle, be sure to wash it thoroughly so it is free from any potentially harmful substances.
Garlic and onion both control slugs and similar pests when mixed with liquid. If slugs are already present in the garden, spraying them with the garlic or onion mixture will kill them on contact.
To make a gallon of insecticide, peel and chop three to five cloves of garlic or one small onion and mix it with water, alcohol or oil as described in the next paragraph. Macerating the garlic or onion as much as possible ensures the active ingredients will leach into the fluid. For best results use a blender.
Alcohol and oil will add potency to the organic spray. Use food-grade materials such as vodka and cooking oil, because they are made from natural sources and are safe for consumption. Alcohol is harmful to many pests and also will help dissolve the solid ingredients, making the insecticide more effective. Do not use the alcohol straight; instead, mix several tablespoons into one gallon of water. Oils will smother insects, but using too much can kill plants as well. Mix one cup of oil with water and the garlic mixture to make a gallon of insecticide.
Hot peppers will keep away small animals such as squirrels, rabbits and groundhogs in addition to repelling insects. Crush chilies such as jalapenos and add them to liquid using the same technique as with the garlic. One small hot pepper can be quite potent and will provide enough protection for a gallon of liquid. Powdered spices equivalent to a single pepper can also be added to the spray but the product will not be as powerful. One tablespoon is usually enough for a gallon.
You can make an organic insecticide combining of all of the above ingredients. One gallon of water blended with a few cloves of garlic, a small onion, a fresh hot pepper, a few tablespoons of vodka and a cup of cooking oil will protect your garden from many types of pests. Strain the mixture before pouring it into a spray bottle to avoid clogging the nozzle.
Dry insecticides also help to protect plants against fungus. Powdery substances need to be reapplied frequently if they are disturbed by rain or wind. Similar to the wet mixtures, dry spreads can be blended to contain more than one active ingredient.
Ground spices and herbs repel a wide array of insects. Cloves kill bothersome flying insects. Ground mint leaves ward off aphids and cabbage worms and deter squirrels. Dried and crushed lavender repels mice and moths while attracting insect-eating butterflies. Cabbage worms dislike such common spices as thyme and oregano. Oregano also discourages cucumber beetles.
Mixing the dried herbs with a filler creates an easier way to disperse the insecticide. As a rule, one part active ingredient to three parts filler will make an effective dry pesticide. Cornmeal is a good choice because it is inexpensive and will prevent mold from growing on the leaves it touches. Tea leaves can also be used to scatter the spices. In addition to preventing fungal growth tea can inhibit bacteria.
When blending multiple herbs, avoid mixing two equally strong-smelling ingredients together, such as clove and lavender, or the effectiveness of their scents will be canceled out. Instead, blend ingredients that tackle the same problem. For example, add a few tablespoons of both thyme and oregano to three cups of cornmeal for a powerful cabbage worm repellent. One tablespoon of ground cloves mixed with three cups of dried tea leaves will hold off aphids and flies and also protect the garden from fungus and bacteria.
Adding rose oil to a lavender and cornmeal mixture will increase its butterfly- attracting properties. Grind a cup of lavender buds, mix with three cups of cornmeal and add a few drops of essential rose oil.