Hi Julie, Simply mix a few teaspoons of liquid dish soap with one quart of water, then spray or wipe the solution onto the leaves, stems, and buds of the plant.
on what? detergent/soap on veggies not good, can burns plants. Neem oil is non-toxic https://www.arbico-organics.com/category/aphid-control-prevention-ipm
A botanist I follow recommends using Dr Bronners to make a soap spray. A few squirts of Dr Bronners castile soap in a spray bottle of water. Spray on the underside of the leaves.
Also, garden centers sell vials of ladybugs. They eat aphids.
They come out early in the morning. Blasthem of your plants with the hose, then spray the plant with soapy water.