Q.Soil Detoxification
The previous tenants in my house left a lot of trash in the backyard. As I dig deeper around the yard, I have found things like styrofoam, paint can lids, plastic, etc. I have not tested the soil, but this cannot be safe to start a garden in. I have read that certain plants like corn, mustards, sunflowers, fava beans and so on have the ability to take in heavy metals and contaminates. My question is, do I have to wait a few years for anything to be edible to eat in the yard, or can making these plants “companion plants” along with other things I anticipate on eating safe to eat?

Certified GKH Gardening Expert
This article may help: https://www.gardeningknowhow.com/garden-how-to/soil-fertilizers/contaminated-soil-treatment.htm