I've found all sorts in potting compost I've bought from hardware & gardening stores in the past. They used to sell good compost but now the quality is not the same. I've also had a lot of plants decline in some home potting compost I've bought so I tend to buy coco coir bricks now and I just add nutrients and perlite with some worm castings and sphagnum moss. I know some people wont use it but its been great and I've had no issues with using it.
