When To Apply Natural Pesticides & 5 Recipes To Start With

Synthetic pesticides are no doubt effective at keeping critters out of the garden, but their potency comes at a cost. Not only can they negatively affect soil and water health, but they've also been associated with respiratory and hormonal issues in humans1. Not to mention, they tend to kill off all insects—even beneficial ones that keep your garden flourishing, like pollinators.

Instead of spraying chemicals at the first sight of a pest problem, organic gardeners will take a more gentle and preventive approach. "When I think of pest management, I think more about how I can create a really healthy environment for my plants and my garden," Sarah Lozanova, environmental journalist and author of Humane Home: Easy Steps for Sustainable & Green Living, tells mbg.

While they likely won't be as disruptive to your garden as chemical pesticides, these natural remedies should still be sprayed sparingly. Use your best judgment when deciding where they're needed.

"If you have a fire ant problem right next to your porch where you like to sit, maybe it makes sense to be more aggressive. But if it's more like a few little ants in the corner of the yard that aren't really hurting anything, then it might not warrant doing something that could harm other critters," Lozanova says.

Available in most home goods stores and online, diatomaceous earth is made from fossilized algae that have been ground into a light powder. Kris Bordessa, a green living expert and the author of Attainable Sustainable: The Lost Art of Self-Reliant Living, prefers using it instead of chemical pesticides in her garden—especially on crops that she plans to feed her family.

"This finely powdered dust doesn't poison insects; it dries them out by absorbing oils from their exoskeletons," she says of the nontoxic material. "The sharp edges of diatomaceous earth particles are abrasive and will roughen the exoskeleton, speeding up the drying process so the pests die quickly."

This naturally occurring bug killer comes from the seeds of the neem tree, Azadirachta indica. "I use neem oil primarily as a foliar (leaf) spray in the garden, to keep pests like aphids at bay. It's also great for helping keep powdery mildew under control," says Bordessa.

Azadirachtin, the main active ingredient in neem oil, is toxic to some bugs. Once they eat it, it disrupts their hormones, makes it harder for them to lay new eggs, and suppresses their appetite until they eventually starve. You can either spray it on your plants as a preventive measure or apply it where you see small, soft-bodied bugs.

Similar to diatomaceous earth, eggshells act as an abrasive in the garden and may be helpful for keeping crawly critters from getting into your plants. While there isn't as much evidence for this one, it's a simple ingredient that most of us already have in our kitchens so it's worth a shot—especially if you live in a warm, moist area that's prone to slugs and snails. Not to mention, the calcium in eggshells can act as a nice soil amendment.

Speaking of common household ingredients, in addition to serving as a body wash, all-purpose spray, detergent, carpet cleaner, and more, multipurpose Castile soap can also help trap and suffocate soft bugs like aphids. And since it's made from vegetable oils, it shouldn't harm other critters or throw off the balance of your garden. Castile soap can also help disperse oils like neem oil in water, making other DIY sprays more effective.