Pesticides from a garden centre are not only costly – they can also be toxic to beneficial insects and birds and toads that eat affected insects. Some pesticides leave a residue in the soil that can be soaked up by other plants. Avoid those problems – and save money – by growing your own pesticides!
Tomatoes are the number one vegetable crop grown by home gardeners in the United States. Of course, we grow them for their delicious fruits. But did you know you can use the leaves to make a spray that is deadly to aphids? Tomato leaves contain chemicals that are toxic to the little bugs. If you are growing tomatoes anyway, this pesticide can be a free by-product! Be sure to hold the plant firmly in one hand when picking the leaves so as not to disturb the roots, and take leaves from the bottom of the plant, away from tomato buds or fruits.
For a plant that not only makes a great pesticide, but looks great, too, try pyrethrum daisies. Pyrethrum-based sprays have been around since the late 1800s. The plants contain a compound known as pyrethrin, fatal to many insects, and especially effective in destroying sucking bugs, like aphids, thrips, mealy bugs, and scale. Some pet flea treatments also contain pyrethrin.
And when you are planning your vegetable garden, do not forget to add a few hot pepper plants. Even if their spiciness does not agree with your palate, they make the basis of a highly effective spray that deters both insects and four-legged pests.
Tomato Leaf Spray
To make the spray, gather 2 cups of leaves from the bottom of the plants, away from tomatoes or flowers. Chop the leaves and soak them overnight in 2 cups of water. Drain the liquid and add 2 more cups of water. Put the mixture in a clean spray bottle and use to spray the undersides of leaves where aphids hide.
Some people with ragweed allergies are sensitive to the powder made from pyrethrum flowers. If you have allergies, wear a mask to be safe.
Gather pyrethrum flowers on a dry day, preferably in the mid- to late afternoon when moisture levels are at their lowest. Flowers can be dried naturally in the sun or in a slow oven. Once dry, you can store the flowers until you need them. To make the spray, grind flowers to a fine powder using an old coffee grinder or blender (check yard sales for these) or a mortar and pestle. Grind only as much as you need – the oil in the flowers loses its volatility over time. Using a funnel, transfer ½ cup powdered flowers to a plastic gallon milk jug and fill the jug with water. Shake the jug and leave it too steep for a few hours or overnight. Shake the jug again and then use a coffee filter or fine cheesecloth strain the liquid into a bucket. Put the mixture in a clean spray bottle and spray on both sides of plant leaves.
Hot Pepper Spray
First, put on rubber gloves! Hot peppers and their extracts can burn! Puree ½ cup hot peppers and 2 cups of water in your blender. Strain into a clean spray bottle and spray both top and bottom of leaves.