Many natural pest control methods exist for the garden but have somewhat fallen into disuse with the rise of chemical products. Now, recent bans on use of pesticides for individuals in some cities are leading to many advances in natural protections. Growing aids, ready-to-use compost teas, and common products like talc, fructose and soap instill the idea that it is possible and easy to cultivate gardens without fearing for our health.
Provide good soil, rich and fertile. Soil is the first thing to consider. It’s not just a medium for plants to grow, but a true living factory made up of billions of organisms. Worms, insects, fungi, bacteria, algae, etc., work in synergy to build up quality soil. Any imbalance weakens plants and may lead to a pest invasion. Organisms in the soil play a key role in maintaining plant health. Think about favoring them by regularly feeding your garden with compost, plant waste, manure, weedy tea, and organic fertilizers. Their work gradually transforms organic matter into mineral matter that plants can use.
Rock powders with high magnesium (Mg) content such as zeolite, dolomite, basalt, or marine algae strengthen the immune system of all living organisms. The more wildlife in the garden, such as birds, amphibians, hedgehogs, and insects, the more helpers there are to control pests in the garden. These unfortunately are direct victims of chemical treatments, yet another reason to avoid them.

Regularly monitor tips of shoots and the underside of leaves to detect pest presence. Act at the onset of attack with a hose and nozzle jet or with a solution of soapy water (a tablespoon of black soap per quart). Hot water, provided it does not exceed 104°F (40°C), also has a repellent action on these pests. Also try preparing an onion peel infusion or a garlic decoction, macerated for 24 hours in boiled water or use plant compost teas. Compost teas of nettle, ferns, horsetails, etc. are even sold ready-to-use in garden stores!
To go further:
The garden holds several home-made or shop-bought preparations that act on soft-bodied pests without chemical pesticides. The table sets them side by side, with what each one reaches and where each one stops.
| Method | Best against | How to use | Main limit |
|---|---|---|---|
| Hose and nozzle jet | Aphids and mites | Dislodge colonies on shoot tips and leaf undersides | Only useful if you spot the attack at its onset |
| Hot water | Aphids and mites | Water that has cooled to no more than 104°F (40°C) | Repellent action only, it does not kill the colony |
| Black soap solution | Aphids, mites, young scale insects | Diluted in soft or slightly acidic water, vinegar added if needed; a teaspoon of rubbing alcohol per quart against young scale | Works on contact only, so repeat sprays are needed |
| Onion peel infusion or garlic decoction | Aphids and mites | Macerated for 24 hours in boiled water, then sprayed | Home preparation, to be made fresh each time |
| Plant compost teas | Aphids and mites | Nettle, fern or horsetail teas, also sold ready to use | Needs repeating through the growing season |
| Nettle manure | Aphids, red bean mite, codling moth, flea beetle | Applied every 7 to 15 days | Must be brewed and diluted before use |
Pyrethrum stays in reserve for the difficult cases, since it paralyses every insect it touches.
Fruit trees often fall prey to worms, aphids, caterpillars, and other pest insects that force your hand regarding tree treatment. The challenge lies in acting before the pest has entered the fruit. Thus, it’s appropriate to intervene from the springtime onward:

Pheromone traps provide an effective way to trap pests once you know which one to target. They work by luring insects into a water bath to drown it, or by trapping it in sticky material (Delta trap).
Read: Pheromone traps: uses in the vegetable patch and ornamental garden
Soak 2.6 ounces per quart for fresh leaves (75 g/L) or 0.5 ounce per quart for dry leaves (15 g/L) for 3-4 days at 68°F (20°C) in drinking water. Filter the plant material out (compost it) and dilute the filtrate in 5 times its volume in drinking water (dilution by 6).
Source: http://substances.itab.asso.fr/wp-content/uploads/2018/08/urtica.pdf