Sis's father in law recommended it. You can buy actual growbags some of which come filled with compost or if you're upcycling/poor you can use an existing bag - hessian lets the water out if there's too much rain, being breathable which is an advantage over a tub. Just fill most of the way with compost and plant as usual :)
This is quite a nice article about it https://www.gardeningknowhow.com/edible/vegetables/potato/growing-potatoes-in-bags.htm
Best of luck! :D