Composting to improve the soil in your garden is one of nature’s best practices, BUT
You have to be careful about what you are throwing into your compost pile. Many chemicals from pesticides and herbicides will wreak havoc and you won’t necessarily know about it until it is too late.
Here is a post from David Goodman, a Bioneer blogger.
There is much more out there about this, but the idea I want to get into your head is that you have to know where things come from and what the practices used were. You are being so careful to have an organic, happy, healthy garden, don’t let your compost pile ruin it.