I was checking the website I’d used for spud planting instructions to see what it said about watering. And I’ve only just realised it said one chitted potato per bag. https://www.thompson-morgan.com/how-to-grow-potatoes-in-bags I’ve 2 in the bag and 2 in a huge plant pot. Oh well, if Mum’s friend could accidentally grow a good crop in her compost heap, these ones might be ok.