for aphid control timing is critical if you want to minimize toxin use, monitor your plants closely, spray before plants start to suffer
A good product is called "Safer Soap" and it is specifically labeled for use as a pesticide. All soaps are fairly toxic to most insects. Some home remedies include using dish soap, but the advantage to using something labeled as a pesticide is you get some guarantee of effectiveness on listed bugs and specific mixing and personal safety instructions. I believe its ok for "organic gardening" but if you are going to be certified as an organic grower you'll need to check with your inspector.
ants are a different issue, they own the earth, we just fool ourselves with lawyers and paper.
Do not use contact insecticides. Even if they are labeled for use as an organic control, you will not succeed unless you get the toxin on the queen. Only 5-10% of the ants in a colony come out to forage for food. The rest have inside jobs. If you use contact pesticides, you only effect the foragers and the factory is still in operation. Baiting is the most effective control for ants. The foragers carry the poison food home. They all share and die (in concept). Of course there are exceptions. Some ants are picky eaters.
There are a few good ant baits available on the market. Combat granular is one of my favorites. I don't know if it is approvable for a organic operation. The catch 22 here is that if you don't apply it to the plants and you don't put it in the soil, then you may not be violating organic gardening pesticide standards. You can accomplish this by placing bait in a container and letting the ants take what they will. Then pick up what they dont take. I put 1 teaspoon of combat granular in a bottle lid and let the ants take it for a few hours. I watched to be sure they were taking it. When I picked it up, there was more than 3/4 left. In ten days the ants were gone. Amdro (it may be sold under a different name now) is another good bait, plus its cheap.
You also can make your own. The hardest part about making your own is to limit the toxin. Boric acid is very effective in the 1-3% by weight range. Over 5% seems to kill before the poison works through the whole colony. Its takes very little bait to kill the whole colony. A teaspoon is enough for dozens of colonies of most ants. Jellies are common bases for boric acid. Apple mint seems to be the most universal. If the ants like it and the toxin is dilute it will work. good luck gobug