Aphids especially hate the strong scent of marigolds and catnip, so they make great companion plants for valuable crops you’re trying to protect.
Good trap crops for aphids include nasturtiums, calendula, and nettles. Once the aphids swarm these sacrificial plants, pull them up and throw them in the trash.
The water will also rinse some of the “honeydew” off and prevent an ant infestation at the same time.
Make sure you only use insecticidal soap where you see aphid colonies—typically on the undersides of leaves—and not resort to spraying the entire plant.
The rock is easily crumbled into a fine white powder that’s harmless to humans (so long as one takes ordinary precautions against excess inhalation) but deadly to pests like aphids.